@article {49961, title = {Endophyte Microbiome Diversity in Micropropagated Atriplex canescens and Atriplex torreyi var griffithsii}, journal = {PLoS ONE}, volume = {6}, year = {2011}, chapter = {e17693}, abstract = {Microbial diversity associated with micropropagated Atriplex species was assessed using microscopy, isolate culturing, and sequencing. Light, electron, and confocal microscopy revealed microbial cells in aseptically regenerated leaves and roots. Clone libraries and tag-encoded FLX amplicon pyrosequencing (TEFAP) analysis amplified sequences from callus homologous to diverse fungal and bacterial taxa. Culturing isolated some seed borne endophyte taxa which could be readily propagated apart from the host. Microbial cells were observed within biofilm-like residues associated with plant cell surfaces and intercellular spaces. Various universal primers amplified both plant and microbial sequences, with different primers revealing different patterns of fungal diversity. Bacterial and fungal TEFAP followed by alignment with sequences from curated databases revealed 7 bacterial and 17 ascomycete taxa in A. canescens, and 5 bacterial taxa in A. torreyi. Additional diversity was observed among isolates and clone libraries. Micropropagated Atriplex retains a complex, intimately associated microbiome which includes diverse strains well poised to interact in manners that influence host physiology. Microbiome analysis was facilitated by high throughput sequencing methods, but primer biases continue to limit recovery of diverse sequences from even moderately complex communities.}, doi = {doi:10.1371/journal.pone.0017693}, url = {/files/bibliography/11-004.pdf}, author = {M.E. Lucero and Unc, Adrian and Cooke, Peter and Dowd, Scot and Sun, Shulei} } @proceedings {49962, title = {Examining endophyte interactions within fourwing saltbush (Atriplex canescens)}, volume = {XVI}, year = {2011}, month = {06/2011}, pages = {159-164}, publisher = {The Berkeley Electronic Press}, address = {Bozeman, Montana}, abstract = {Cryptic endophyte consortia associated with embryonic tissues of fourwing saltbush (Atriplex canescens) are believed to serve mutualistic functions. However, the complexity of these endophyte communities makes cause-and-effect relationships difficult to establish. In fourwing saltbush, cryptic endophytes are thought to enhance drought and salt tolerance, nutrient acquisition, germination, and establishment. Some of these traits can be conferred to alternate host plants by co-culturing seedlings in vitro with micropropagated fourwing saltbush callus. Here we describe an evolving process for; 1) identifying arrays of cryptic, seed borne endophytes associated with fourwing saltbush; 2) evaluating early vigor of grasses and other plants endowed with fourwing saltbush endophytes; 3) selecting plant-endophyte combinations with increased tolerance to abiotic stressors, and 4) monitoring the persistance of transferred endophytes across plant generations in increasingly complex habitats. This process is designed to evaluate specific plant-fungal interactions that influence host tolerance to salinity, but may be broadly adaptable for selecting endophyte-enhanced plant germplasms with a variety of desired traits.}, keywords = {Atriplex canescens, browsing, cryptic endophyte consortia, embryonic, fire, herbivory, monitoring, proceedings, sagebrush, wildland shrubs}, url = {/files/bibliography/08-056.pdf}, author = {M.E. Lucero and J.R. Barrow and I. Reyes-Vera and Ruth L. Sedillo} } @article {50047, title = {Composition of Ceanothus gregii oil as determined by steam distillation and solid-phase microextraction}, journal = {Journal of Essential Oil Research}, volume = {22}, number = {2}, year = {2010}, pages = {140-142}, abstract = {Ceanothus gregii Gray was collected from the Jornada Experimental Range in south central New Mexico. Current year{\textquoteright}s growth was collected from ten plants found within an approximate 50 m radius of the GPS coordinates N32{\textdegree}40.605{\textquoteright} and W106{\textdegree}33.486{\textquoteright}at an altitude of 1,741 m during July 2001. Composite samples of the plants were steam distilled in triplicate, and the composite oil was analyzed using both GC-FID and GC/MS. The volatile composition of the same plants was also examined using solid-phase microextraction (SPME) with a 100?m polydimethylsiloxane fiber. Mass spectra and retention indices were used to identify 41 previously described compounds. Methyl salicylate (16.8\%), hexenal (11.8\%) and n-decanal (7.0\%) were the major identified compounds.}, keywords = {Ceanothus gregii, essential oil composite, hexanal, methyl salicylate, Rhamnaceae}, url = {/files/bibliography/10-02.pdf}, author = {M.E. Lucero and Richard E. Estell and E.L. Fredrickson} } @inbook {50048, title = {Examination of seed-borne endophyte microbiomes}, booktitle = {Prospects and Applications fo Plant-Associated Microbes. A Laboratory Manual Part B: Fungi}, year = {2010}, chapter = {Examination of seed-borne endophyte microbiome}, abstract = {Plant microbiomes include numerous seed associated microbes which are vertically transferred to progeny. These complex microbial communities have not been heavily reported in scientific literature, possibly because they are difficult to detect and monitor. Yet potential for seed borne microbes to influence host plant performance across generations suggests opportunity for exploiting microbes to enhance host plant adaptation across changing habitats. The chenopod species Atriplex canescens offers a valuable model system in which to correlate the distribution of endophtye microbiomes with plant adaptation to stressed habitats. Broadly distributed across arid and saline habitats, the species is known for its restoration potential, complex genetics, and diverse microbial associations. The species lends itself well to micropropagation, and numerous fungal and bacterial species have been observed in micropropagated lines initiated from disinfested seeds. Hence, these micropropagated lines provide useful systems through which interactions between seed borne microbes and the plant itself can be systematically examined to improve understanding of microbial contributions to plant fitness. The shift from investigating plants as single entities to observing plants as lichenous consortia of mutualistic symbionts promises to expose opportunities for utilizing microbes to maximize plant productivity relative to human agricultural, biofuel, or restoration needs.}, author = {M.E. Lucero} } @article {50049, title = {Using hydrogel filled, embedded tubes to sustain grass transplants for arid land restoration}, journal = {Journal of Arid Enviornments}, volume = {74}, year = {2010}, pages = {987-990}, abstract = {

Grass restoration on remote arid rangelands may require irrigation to stimulate establishment. However, irrigation on undeveloped sites is costly. Vertical irrigation tubes that direct applied moisture to subsurface zones where evaporation is reduced, and hydrogels that prevent applied moisture from infiltrating beyond plant root zones can maximize the portion of applied water available for plant uptake.\  The survival and growth of Bouteloua eriopoda (Torr.) Torr. transplants irrigated with either starch- or acrylic-based hydrogels contained in one of three embedded watering tube styles were evaluated in a greenhouse trial. A field trial evaluated differences in transplant survival and cover between treatments consisting of embedded watering tubes with or without acrylic hydrogels. Greenhouse transplants from all treatments grew 146 days on less than 1 L of water. Plants irrigated with starch hydrogels consumed the most water and exhibited the most growth. Variations in tube styles had minor effects on plant growth and water loss from tubes. In the field, heavy growing season precipitation was observed, and transplant survival was high for both treatments. No significant differences in cover were detected.\  Greenhouse data demonstrate potential for hydrogel filled, embedded tubes to provide adequate moisture for establishment and growth of deep-rooted black grama transplants. Field data indicate deep-rooted black grama transplants establish successfully when adequate moisture is available.

}, keywords = {black grama, remote site irrigation, soil moiste}, url = {/files/bibliography/10-05.pdf}, author = {M.E. Lucero and Dreesen, D.R. and D. VanLeeuwen} } @article {50119, title = {A retention index calculator simplifies identification of plant volatile organic compounds}, journal = {Phytochemical Analysis}, volume = {20}, year = {2009}, month = {August 2009}, pages = {378-384}, abstract = {

Plant volatiles (PVOCs) are important targets for studies in natural products, chemotaxonomy and biochemical ecology. The complexity of PVOC profiles often limits research to studies targeting only easily identified compounds. With the availability of mass spectral libraries and recent growth of retention index (RI) libraries, PVOC identification can be achieved using only gas chromatography coupled to mass spectrometry (GCMS). However, RI library searching is not typically automated, and until recently, RI libraries were both limited in scope and costly to obtain. Objective is to automate RI calculation and lookup functions commonly utilized in PVOC analysis. Formula required for calculating retention indices from retention time data were placed in a spreadsheet along with lookup functions and a retention index library. Retention times obtained from GCMS analysis of alkane standards and Koeberlinia spinosa essential oil were entered into the spreadsheet to determine retention indices. Indices were used in combination with mass spectral analysis to identify compounds contained in Koeberlinia spinosa essential oil. Eighteen compounds were positively identified. Total oil yield was low, with only 5 ppm in purple berries. The most abundant compounds were octen-3-ol and methyl salicylate. The spreadsheet accurately calculated RIs of the detected compounds. The downloadable spreadsheet tool developed for this study provides a calculator and RI library that works in conjunction with GCMS or other analytical techniques to identify PVOCs in plant extracts.

}, keywords = {biochemical, chemotaxonomy, ecology, essential oil, gas chromatography, Koberlinia spinosa, kovatis index, phytochemical analysis, Plant volatiles, PVOC}, doi = {10.1002/pca.1137}, url = {/files/bibliography/09-020.pdf}, author = {M.E. Lucero and Richard E. Estell and M.R. Tellez and E.L. Fredrickson} } @article {50239, title = {A cryptic microbial community persists within micropropagated Bouteloua eriopods (Torr.) Torr. cultures}, journal = {Plant Science}, volume = {174}, year = {2008}, month = {March 16, 2008}, pages = {570-575}, abstract = {

Higher plants are ubiquitously colonized with fungal endophytes, which often lack readily detectable structures. This study examines the diverse endophyte population within a single line of micropropagated Bouteloua eriopoda (Torr.) Torr., using microscopy and comparison of internal spacer (ITS) gene sequences obtained from both plant and isolated fungal tissues. Sequences amplified from three ascomycete and one basidiomycete fungi isolated from a micropropagated line were compared to seven unique, ITS sequences amplified directly from the fungal-laden micropropagated plant tissue. Clone sequences were also compared to grass ITS sequences. Bayesian analysis placed four of the seven sequences in a tight grass clade. The remaining sequences were placed in a more diverse clade representing both cultured and uncultured endophytes. Results confirm a diverse, cryptic endophyte consortium is retained within this micropropagated plant line. The probability that similar complexity is common among higher plants implies a need to revise commonly held assumptions that aseptically propagated plants are axenic. Genes and natural products derived from such systems could be microbial in origin. Meanwhile, while the development of controlled systems in which to study single plant-fungal interactions presents significant technical challenges, the potential to uncover multi-species interactions that influence plant growth and development is high.

}, keywords = {alternaria, Aspergillus ustus, endophyte, Engyodontium album, Moniliophthora, phoma}, doi = {10.1016/j.plantsci.2008.02.012}, url = {/files/bibliography/08-008.pdf}, author = {M.E. Lucero and J.R. Barrow and P. Osuna-Avila and I. Reyes-Vera} } @article {50238, title = {Enhancing native grass productivity by cocultivating with endophyte-laden calli}, journal = {Rangeland Ecology and Management}, volume = {61}, year = {2008}, month = {January 2008}, pages = {124-130}, abstract = {The influence native endophytes have on grass establishment and productivity was evaluated by co-cultivating Bouteloua eriopoda (Torr.) Torr. (black grama) or Sporobolus cryptandrus (Torr.) Gray (sand dropseed) seedlings with endophyte-laden calli from three of four native grass and shrub species; Atriplex canescens (Pursh) Nutt. (fourwing saltbush), S. cryptandrus, S. airoides (Torr.) Torr. (alkali sacaton), and B. eriopoda in-vitro. Following co-cultivation, grass seedlings were hardened and transferred to 3 replicate field plots each containing 16 grass plants of a single species which had been co-cultivated with a single callus species. Plant establishment rates, heights, crown diameters, above ground biomass, seed yields, and seed quality were compared. In B. eriopoda (black grama), significant increases in plant biomass were not observed. However, early plant heights and crown diameters, establishment rates, and stolon production were higher in some callus treatments. In S. cryptandrus (sand dropseed), all variables were positively influenced by one or more of the endophyte treatments. Biomass increases ranged from 2.5 to 3-fold over untreated plants, and harvested seed increased 5.9-fold in plants treated with endophytes from A. canescens (fourwing saltbush). Seed quality, determined by purity, germination rates, and tetrazolium assays, and did not differ across endophyte treatments for either grass. There is evidence that endophyte transfer is responsible for the altered vigor of treated plants, but this conclusion requires further study.}, keywords = {Atriplex canescens, Bouteloua eriopoda, endophytes, native grasses, non-mycorrhizal, Sporobolus airoides, Sporobolus cryptandrus}, url = {/files/bibliography/08-004.pdf}, author = {M.E. Lucero and J.R. Barrow and P. Osuna and I. Reyes-Vera} } @proceedings {50360, title = {Differences in volatile profiles between populations of Ceratoides lanata var. subspinosa (Rydb.) J.T. Howell}, volume = {RMRS-P-47}, year = {2007}, month = {August 10-12, 20}, pages = {142-146}, publisher = {USDA Forest Service, Rocky Mountain Research Station}, address = { Lubbock, TX}, abstract = {Ceratoides lanata (Rydb.) J.T. Howell, common winterfat, is valued for its nutrient content and palatability to livestock. However, the subspecies Ceratoides lanata var. subspinosa (Rydb.) J.T. Howell, first described in the Mojave desert, is considered unpalatable. This characterization has been supported by data from livestock grazing studies at the Jornada Experimental Range in southern New Mexico. Curiously, observation of subspinosa revealed several populations in central New Mexico which were heavily grazed. Volatile terpene profiles have frequently been associated with differences in palatability in various plant species. To determine whether differences in volatile profiles between subspinosa populations would correlate with apparent differences in palatability, plants from 13 populations of subspinosa were collected in the fall of 2000. Volatile analysis of ground shoot samples using solid-phase microextraction and gas chromatography-mass spectroscopy consistently identified 33 compounds. Limonene, myrcene, and 3-carene were the most abundant compounds in all populations, comprising 81\% and 85\% of the volatiles detected in heavily grazed and ungrazed plants, respectively. This is thought to be the first time C. lanata subspinosa volatiles have been described. Compounds present in at least half of either the heavily grazed or ungrazed plants were subjected to a stepwise discriminate analysis of relative quantities. The analysis identified a subset of 14 chromatographic peaks (myrcene, 3-hexenol, 3-carene, AR-curcumene, limonene, n-hexanol, p-cymene, a mixture thought to contain alpha-pinene, alpha-thujene, and tricyclene, a mixture thought to contain n-decanal, and five unknowns) which may distinguish between palatable and unpalatable phenotypes. When a discriminate rule based on these chemicals was applied to chemical data from individual plants at all sites, none of the plants were misclassified. The possibility that these varied oil profiles may be used to distinguish palatable from unpalatable phenotypes is discussed. http://www.fs.fed.us/rm/pubs/rmrs_p047/rmrs_p047_142_146.pdf}, keywords = {ceratoides, lanata, populations, subspinosa, Volatile}, url = {/files/bibliography/07-022.pdf}, author = {M.E. Lucero and Richard E. Estell and D.M. Anderson and E.L. Fredrickson and M.D. Remmenga}, editor = {R. E. Sosebee and Wester, D.B. and Britton, C.M. and McArthur, E.D. and S.G. Kitchen} } @conference {50359, title = {Identification of seed borne endopohytes that confere salt tolerance to host plants}, booktitle = {Plant Biology and Botany 2007 Annual Meetings}, year = {2007}, month = {July 7-11, 2007}, address = {Chicago, IL}, abstract = {The chenopod halophyte, Atriplex canescens (Pursh) Nutt, (fourwing saltbush) is broadly distributed among western rangelands. Its highly variable phenotypes are typically attributed to varied ploidy levels. However, A. canescens is also associated with complex communities of seed borne endophytes. Microscopic examination of these endophytes communities suggests potential roles in stress tolerance. In this study, observational and experimental data are being combined to evaluate microbial contributions to salt tolerance of A. canescens. Initially, Ecological Site Descriptions published through the National Resource Conservation Service are used to identify five optimal and five extreme saline habitats populated with A. canescens. Seeds collected from identified habitats are surface disinfested, and microbes associated with seeds germinating in vitro are characterized using direct isolation and/or denaturing gradient gel electrophoresis (DGGE), followed by sequencing of ribosomal RNA genes (rDNA). At present, four ascomycete fungi and two bacterial species have been isolated. To analyze the manner in which these microbes influence host plant salt tolerance, microbes are transferred to various species of aseptically propagated host plants. Treated and untreated plants are exposed to a range of saline conditions and plant growth is compared across treatments. These rapid bioassays are expected to reveal plant-endophyte combinations with potential to increase plant tolerance to saline conditions.}, keywords = {endopohytes, salt tolerance}, author = {M.E. Lucero and J.R. Barrow and Ruth L. Sedillo and I. Reyes-Vera and Caitriana Steele and Midez, J.} } @conference {50472, title = {Genetic characterization of uncultured fungal endophytes from Bouteloua Eriopoda and Atriplex}, year = {2006}, month = {June 6-8, 2006}, address = {Cedar City, UT}, abstract = {

Obligate fungal endophytes form cryptic communities in vascular plants which can defy detection and isolation by conventional methods. Molecular detection by PCR amplification of fungal DNA sequences alone is insufficient, since target endophyte sequences are unknown and quite similar to sequences already characterized as plant DNA. We have successfully separated fungal and plant ribosomal DNA sequences by amplifying plant-extracted DNA with polymerase chain reaction, and separating sequences with denaturing gradient gel electrophoresis (DGGE). The resulting electrophoregrams produce specific bands unique for each organism present in a specific plant-endophyte community. This method has successfully identified endophytes in B. eriopoda and A. canescens, and has tracked these endophytes as they are transferred to novel host plants. The detection and monitoring capabilities of DGGE make it a valuable tool for discovery, characterization, and monitoring of rangeland endophytes.

}, keywords = {Atriplex, Bouteloua, endophytes, Eriopoda, fungal}, author = {M.E. Lucero and J.R. Barrow and Ruth L. Sedillo and P. Osuna-Avila and I. Reyes-Vera} } @proceedings {50473, title = {Genetic characterization of uncultured fungal endophytes from Bouteloua eriopoda and Atriplex canescens}, year = {2006}, month = {2006}, abstract = {

Obligate fungal endophytes form cryptic communities in vascular plants which can defy detection and isolation by microscopic examination of reproductive structures. Molecular detection by PCR amplification of fungal DNA sequences alone is insufficient, since target endophyte sequences are unknown and difficult to distinguish from sequences already characterized as plant DNA. We have successfully separated fungal and plant ribosomal DNA sequences by amplifying plant-extracted DNA with polymerase chain reaction, and separating sequences with denaturing gradient gel electrophoresis (DGGE). The resulting electrophoregrams theoretically produce specific bands unique for each organism present in a plant-endophyte community. This method has successfully identified endophyte sequences in Bouteloua eriopoda and A.triplex canescens, and has tracked these endophytes as they are transferred to novel host hosts.

}, author = {M.E. Lucero and J.R. Barrow and P. Osuna-Avila and I. Reyes-Vera and Ruth L. Sedillo} } @conference {50474, title = {Native symbiotic fungi increase stress tolerance and productivity of plants in arid lands}, booktitle = {Symposium on Efficient Water Use in the Urban Landscape}, year = {2006}, month = {February 23-24, }, address = {Las Cruces, NM}, abstract = {Plants indigenous to arid lands have evolved to withstand extremes of moisture and temperature. Recent advances in microbial ecology have revealed that a portion of plant stress tolerance comes, not from the plant itself, but from unseen fungi that reside within plant tissues. The ability of these symbiotic fungi to confer drought and salt stress tolerance on plant hosts make them uniquely valuable for landscapes where water is limited or where drip irrigation is utilized. Here we describe fungi associated with four species of Chihuahuan desert plants which can be transferred to non-native hosts. A patent-pending technique was used to transfer these unculturable fungi to native grasses (Bouteloua and Sporobolous species), chile (Capsicum annum), tomato (Lycopersicon esculentum), and shasta daisys (Chrysanthemum maximum). The productivity of recipient plants, measured at various stages in the growth cycle, indicates that fungal recipients fared remarkably well compared to untreated plants receiving equal water and nutrients. Chile plants were also exposed to salt stress trials in which salt stress tolerance varied between endophyte treatments. Fungi from creosote bush (Larrea tridentada) were particularly efficient at increasing salt tolerance.}, keywords = {fungi, microbial ecology, plant stress}, author = {M.E. Lucero and I. Reyes-Vera and Vivenhananthan, E. and J.R. Barrow and Ruth L. Sedillo} } @article {50470, title = {Plant-fungal interactions in Arid and Semi-arid Ecosystems: Large-scale impacts from microscale processes}, journal = {Journal of Arid Environments}, volume = {65}, year = {2006}, month = {April 1, 2006}, pages = {276-284}, abstract = {

The roles microbes play in shaping plant communities have historically been underestimated. Recent improvements in our abilities to detect, identify, and monitor microbial inhabitants of plant tissues are driving appreciation of amazingly complex dynamics. Microbial endophytes can modify plants at genetic, physiologic, and ecologic levels, inducing profound changes in the way plants respond to their environment. Microscale examination of Bouteloua eriopoda (black grama) and Atriplex canescens (four-wing saltbush) has revealed diverse fungal communities associated with individual plants at the cellular and subcellular levels. To explore thresholds of plant fitness defined by microbial communities, we transferred fungi inhabiting two perennial grasses, B. eriopoda and Sporobolus cryptandrus (sand dropseed), and one shrub, A. canescens, to a variety of nonhost plant species. Dramatic, whole-plant differences in morphology and biomass between treated and untreated plants were observed. In most cases, endophyte transfer at the cellular level produced larger plants with greater reproductive potential than the untransformed counterparts. We hypothesize that these transformed plants will continue to grow, reproduce, and disperse more rapidly than their native counterparts, propagating changes from the plant-microbe interface to ecologically significant scales.

}, keywords = {large-scale impacts, microscale processes, plant-fungal interactions}, doi = {10.1016/j.jaridenv.2005.08.014}, url = {/files/bibliography/06-011.pdf}, author = {M.E. Lucero and J.R. Barrow and P. Osuna and Reyes, I.} } @article {50471, title = {Volatile composition of Guiterrizia sarothrae (broom snakeweed) as determined by steam distillation and solid phase microextraction}, journal = {Journal of Essential Oil Research}, volume = {18}, year = {2006}, month = {April 1, 2006}, pages = {121-125}, abstract = {Guiterrizia sarothrae (broom snakeweed, snakeweed) is a prevalent species on rangelands throughout much of the western United States. This plant has been intensely studied in order to minimize its negative impact on forage production and livestock health. Although G. sarothrae has been used for centuries to remedy various ailments, scientific investigations of the plant\¿s medicinal value are difficult to find in the literature. The objective of this study was to explore the volatile chemical composition of G. sarothrae. Shoots from 88 actively growing plants showing no signs of root borer infestation were selected from five sites on the Chihuahuan Desert of southern New Mexico. Volatiles were extracted from ground, composite tissues by steam distillation and by solid phase microextraction (SPME), then separated and analyzed by gas chromatography with mass spectral and flame ionization detection. Comparing retention indices and mass spectra to known compounds identified ninety chemicals. Retention indices and 70 eV mass spectra are also provided for seven unknowns. Compounds detected varied in quantity between extraction protocols. In oil, cryptone (6.4\%) and beta-eudesmol (5.9\%) were the only compounds comprising more than 5\% of the chromatographic peak area. In samples prepared by solid-phase microextraction, limonene (10.4\%), beta-pinene (9.6\%), beta-eudesmol (8.0\%), sabinene (7.8\%), cryptone (6.5\%), alpha-pinene (5.5\%), and ortho-cymene (5.2\%) accounted for 53\% of the extracted volatiles. The results presented reveal a complex volatile composition from which unique compounds may still be identified.}, url = {/files/bibliography/06-013.pdf}, author = {M.E. Lucero and Morrison, A. and E.L. Fredrickson and Richard E. Estell and D. Richman} } @article {50575, title = {The composition of Dalea formosa oil determined by steam distillation and solid-phase microextraction}, journal = {Journal of Essential Oil Research}, volume = {17}, year = {2005}, month = {November 2005}, pages = {645-647}, abstract = {

Dalea formosa Torr. (feather dalea, featherplume) was collected from the Jornada Experimental Range in south central New Mexico. Current year{\textquoteright}s growth was collected from 10 plants, all found within an approximate 50 m radius of the GPS coordinates N32o40.645{\textquoteright} and W106o33.601{\textquoteright} during July 2001. Composite samples of the plants were steam-distilled in triplicate, and the essential oil was analyzed using both GC-FID and GC/MS. To explore the possibility of using solid-phase microextraction (SPME) in place of steam distillation, compositions of plants collected from the same site were also examined using SPME. Mass spectra and retention indices were used to identify 58 previously described compounds. The retention index and EI mass spectra are provided for one unknown. Alpha-pinene (31.7\%), camphene (8.4\%), and limonene (8.1\%) were the major constituents of the oil. Beta-pinene made up only 5.8\% of the oil but accounted for 13.2\% of the SPME chromatogram peak area. This difference in composition may be du to either sampling technique or harvesting time.

}, keywords = {composition, Dalea formosa, solid-phase microextraction, SPME, steam distillation}, doi = {10.1080/10412905.2005.9699022}, url = {/files/bibliography/05-014.pdf}, author = {M.E. Lucero and Richard E. Estell and Ruth L. Sedillo} } @conference {50574, title = {Enhancement of chile biomas, fruit quality, and drought stress tolerance by inoculation with native plant endophytes}, booktitle = {20th Annual Southwest Consortium on Plant Genetics and Water Resources}, year = {2005}, month = {August 18-20, 20}, pages = {6}, publisher = {Texas A\&M}, organization = {Texas A\&M}, address = {Santa Ana Pueblo, NM}, abstract = {Recognition of the important contributions endophytes make to plant stress tolerance, defense, and production has grown exponentially with improvements in detection of unculturable microorganisms in plant tissues. Recently, the ability to manipulate host-endophyte combinations has provided a powerful tool for plant improvement and offered a host of new opportunities for metabolic engineering. Endophytes obtained from plants native to the Chihuahuan desert have demonstrated remarkable potential to transform forage grasses, tomatoes, and Arabidopsis, increasing overall biomass, nutrient uptake, and fruit production. The mechanisms by which these improvements occur are not fully understood. Microscopic examination of fungal biofilms on plant surfaces, in guard cells, and in vascular tissues suggest direct roles in water and nutrient management. The proposed study will utilize chile plant as model systems for analysis of changes in gene expression and metabolism following inoculation with foreign endophytes. Treated and untreated chile will be raised from seedlings in a controlled greenhouse environment. PCR and in situ hybridization of leaf tissue will verify changes in systemic endophyte populations following inoculation. Plant growth measurements such as height, days until flowering, numbers of flowers and fruit produced and biomass will be recorded. Samples from young and mature tissues will be harvested for biochemical analysis of organic extracts, and for RNA analysis. Gene expression analysis will determine the abundance of transcripts related to drought stress, photosynthesis, and secondary metabolism. This research will directly address SWC goals of determining and evaluating plant genetic, developmental, biochemical, and physiological responses that affect the growth and yield of a regionally important crop species.}, keywords = {endophytes, microorganisms, plant tissues}, author = {M.E. Lucero and M. A. O{\textquoteright}Connell} } @conference {50576, title = {Whose genes are we sequencing? Evidence for the presence of multiple genomes in native and regenerated high plants}, booktitle = {American Society of Plant Biologists}, year = {2005}, month = {October 12-16, 2}, pages = {Paper No. 33}, address = {Snowbird, Utah}, abstract = {Plant genome analysis has been traditionally based on an assumption that healthy plants are axenic organisms. With improved techniques for detecting microbial endophytes, evidence supporting the presence of microbial consortia associated with all major plant tissues is mounting. Herein, the isolation and/or detection of seven species of fungi associated with the desert grass, Bouteloua eriopoda are described. Also described are three species of fungi and one bacterium isolated from aseptically cultured Atriplex canescens. The detection of fungal lipids and chitin in more than 40 species, including surface sterilized Arabidopsis thailiana indicate symbioses with asymptomatic endophytes are well conserved in higher plants. In some cases, endophyte DNA sequences have aligned more closely with host plant sequences reported in Genbank than with DNA from related groups of endophytes. For example, a bacterial endophyte independently isolated from A. canescens and A. confertifolia contains a sequence similar to internal spacer rDNA reported for 131 species of the plant family Chenopodiacea. In grasses, teliospore producing endophytes are highly conserved. DNA hybridizing to one such endophyte in B. eriopoda aligns closely with sequences from rice. The overwhelming evidence that higher plants exist as communities interacting with populations of microbial endophytes has powerful implications for plant molecular biologists. It is inadequate to assume that DNA isolated from plant tissues is plant DNA.}, keywords = {DNA, endophytes, fungi, plant genome}, author = {M.E. Lucero and J.R. Barrow} } @conference {50685, title = {Implications of plant-fungal interactions: can microscale processes have macroscale impacts?}, booktitle = {Sixth Symposium on the Natural Resources of the Chihuahuan Desert Region}, year = {2004}, month = {October 25, 2004}, pages = {32}, address = {Alpine, TX}, abstract = {The roles microorganisms play in shaping desert plant communities have often been underestimated. Recent tools expanding our abilities to detect, identify, and monitor microbial inhabitants of plant tissues are providing new insights to amazingly complex systems. Microscale examination of Boutelouaeriopoda (black grama grass) and Atriplexcanescens (fourwing saltbush) has revealed diverse fungal communities living within individual plants. The compositions of these fungal communities are apparently dictated by multiple factors. We believe these internal fungi assist the plant with water and nutrient transport, drought tolerance, and defense against herbivores and pathogens. To explore thresholds of plant fitness that are defined by microbial communities, we transferred fungi inhabiting Boutelouaeriopoda, Atriplex canescens, and Sporobolus cryptandrus to eight, nonhost plant species. Dramatic, whole-plant differences in morphology, water potential, chlorophyll content, dates to maturity, seed production and marker gene profiles, and more between treated and untreated plants, were observed. In most cases, endophyte transfer at the cellular level produced astonishingly robust plants with greater reproductive potential than the untransformed counterparts. The dramatic changes observed in plants with altered microbial populations illustrate the propagation of cellular-level changes to whole-plant and progeny-scale impacts. We hypothesize that these transformed plants will continue to grow, reproduce, and disperse more rapidly than their native counterparts, propagating changes from the plant-microbe interface to ecologically significant scales. Broad-scale factors limiting this process are being explored.}, keywords = {black grama, desert plant communities, fourwing saltbush, macroscale impacts, microscale processes, plant-fungal interactions}, author = {M.E. Lucero and J.R. Barrow} } @article {50793, title = {The essential oil composition of Psorothamnus scoparius (A. Gray) Rydb.}, journal = {Journal of Essential Oil Research}, volume = {15}, number = {2}, year = {2003}, month = {March 1, 2003}, pages = {108-111}, abstract = {Psorothamnus scoparius (broom dalea) was collected from the Jornada Experimental Range in south central New Mexico. Current year{\textquoteright}s growth was collected from 10 plants, all found within an approximate 50 m radius of the GPS coordinates N 32 deg 41.286{\textquoteright} and W 106 deg 46.922{\textquoteright} during June 2000. Composite samples were steam distilled, and the essential oil was analyzed using GC with FID and GC/MS. Mass spectra and retention indices were used to identify 65 previously described compounds. Retention indices and EI mass spectra are also provided for 15 unknowns. Gamma-terpinene (22.3\%), para-cymene (14.0\%), and alpha-pinene (9.0\%) were the major constituents of the oil.}, keywords = {broom dalea, composition, essential oil, Psorothamnus scoparius}, url = {/files/bibliography/03-018.pdf}, author = {M.E. Lucero and Richard E. Estell and E.L. Fredrickson} } @conference {50903, title = {A comparison of Dalea formosa oils isolated by steam distillation and by solid-phase microextraction}, booktitle = {Society for Range Management, New Mexico Section Winter Meeting}, year = {2002}, month = {January 8-10, 20}, pages = {Abstract 6}, address = {Las Cruces, NM}, abstract = {Dalea formosa Torr. (feather dalea, featherplume) was collected from the Jornada Experimental Range in south central New Mexico. Current year{\textquoteright}s growth was collected from 10 plants, all found within an approximate 50m radius of the GPS coordinates N 32 deg 40.645{\textquoteright} and W 106 deg 33.601{\textquoteright} during July 2001. Composite samples of the plants were steam distilled in triplicate, and the essential oil was analyzed using both GC-FID and GCMS. Compositions of plants collected from the same site were also examined using Solid Phase Microextraction (SPME). Mass spectra and retention indices were used to identify 58 previously described compounds. All of the compounds identified in the essential oil were also seen by SPME either by GCMS or by FID. Relative amounts of some compounds varied. Differences may be due to either sampling technique or harvesting time. The advantages of using SPME include the need for much less plant material, more rapid and dreproducible sample preparation, less opportunity for oxidation of volatiles to occur, and no need for the use of organic solvents.}, keywords = {comparison, Dalea formosa, solid-phase microextraction, steam distillation}, author = {M.E. Lucero and Richard E. Estell and Ruth L. Sedillo} } @conference {50905, title = {Landscape-level phytochemistry of a Chihuahuan Desert shrubland}, booktitle = {Annual Meeting, Phytochemical Society of North America}, year = {2002}, month = {July 20-24, 2002}, pages = {49 (Abstract No. 17)}, address = {Merida, Mexico}, abstract = {Shrub volatiles play a significant ecological role in desert rangelands. Activities attributed to these compounds include pollinator attraction, herbivore repulsion, allelopathy, pathogen inhibition, and microclimate modification. In recent years, we have constructed volatile chemical profiles of a number of genera, including Ceratoides, Chrysothamnus, Dalea, Drymaria, Dyssodia, Fallugia, Florensia, Gutierrezia, and Psorothamnus. Presently, we are utilizing these data to construct a spatial database of the volatile compounds present on sites within the 78,266 ha Jornada Experimental Range (JER), a desert rangeland research facility near Las Cruces, NM. Coupling these data with vegetative maps, soil maps, livestock grazing patterns, weather and climate data, and other information available at the Jornada Experimental Range will facilitate examination of relationships between plant volatile composition, shrub survival, plant-plant competition, and plant-herbivore interactions.}, author = {M.E. Lucero and Richard E. Estell and M.R. Tellez and E.L. Fredrickson and Kris Havstad} } @conference {50904, title = {Rapid profiling of shrub volatiles using solid-phase microextraction (SPME) and gas chromatography with mass spectroscopy (GC-MS)}, booktitle = {12th Wildland Shrub Symposium}, year = {2002}, month = {August 12-16, 20}, pages = {27}, address = {Laramie, WY}, abstract = {Shrub volatiles play a significant role in the chemical ecology of desert rangelands. Activities attributed to these compounds include pollinator attraction, herbivore repulsion, allelopathy, pathogen inhibition, and microclimate modification. Since the mid 1980{\textquestiondown}s, advances in laboratory instrumentation and computer software have dramatically reduced the capital and labor costs of sample processing and chemical analyses, expanding the capabilities of small laboratories. Mass spectral databases now include many natural products, and commercialization of Solid Phase Microextraction (SPME) by Supelco Corporation has made routine preparation of thousands of samples feasible for one technician. Here we describe ways we are using SPME, gas chromatography (GC-FID), GC-MS, and mass spectral libraries to rapidly profile, identify, and quantify individual volatiles released by shrubs. Completed profiles include volatile compositions of Ceratoides, Flourensia, Psorothamnus, Dalea, and Gutierrezia, with additional species currently under examination. These profiles can all be obtained by field sampling less than a gram of plant material. The low biomass requirement for sample preparation enables tissue specific sampling with many replicates. Samples are currently cooled under dry ice and transported to the laboratory for SPME followed by GC-MS and GC-FID analyses. Optimization of methods for on-site SPME and gas chromatography is currently underway and will be useful for routine monitoring of shrub volatiles.}, author = {M.E. Lucero and Richard E. Estell and Yi Wang} } @conference {50902, title = {Secondary metabolite profiles of palatable and unpalatable populations of ceratoides lanata}, booktitle = {55th Annual Meeting, Society for Range Management}, year = {2002}, month = {February 13-19, }, pages = {Abstract No. 86}, address = {Kansas City, MO}, abstract = {Ceratoides lanata var. lanata (common winterfat) is a prolific chenopod on rangelands throughout the western United States. The plant is valued by livestock producers for its nutrient content and palatability to livestock. The subspecies C. lanata var. subspinosa, native to the southwestern U.S. and northern Mexico, is reported to be unpalatable to livestock. Curiously, fenceline observations of C. lanata var. subspinosa growing north of the Chihuahuan Desert suggest its palatability varies. The availability of palatable and unpalatable phenotypes make C. lanata and C. lanata var. subspinosa useful models to use for identification of secondary compounds influencing diet selection. In this study, actively growing shoots from 10 winterfat populations (10 plants per sampling) in New Mexico, Utah, and west Texas were sampled in early, mid, and late phenological stages. Samples were separated into palatable and nonpalatable populations. Steam distillation of composite samples reveale extremely low levels of volatiles, discouraging further analysis of winterfat volatiles. Nonvolatiles were extracted in 80\% ethanol and separated by liquid chromatography with photodiode array detection. Peaks which differ significantly between populations are being identified by uV and mass spectroscopy and by comparison with standards when available. Differences in chemical profiles between palatable and unpalatable winterfat populations will point to chemicals that influence diet selection among large ruminants.}, keywords = {ceratoides ianata, metabolite profiles, palatable, unpalatable}, author = {M.E. Lucero and Richard E. Estell and D.M. Anderson and E.L. Fredrickson and Kris Havstad and M.D. Remmenga} } @article {51169, title = {Tolerance to nitrogenous explosives and metabolism of TNT by cell suspensions of datura innoxia}, journal = {In Vitro Plant}, volume = {35}, number = {6}, year = {1999}, month = {November 1, 1999}, pages = {480-486}, abstract = {

Cell suspension cultures of Datura innoxia were incubated in the presence of the nitro-substituted explosives 2,4,6-trinitrotoluene (TNT), 1,3,5-trinitro-1,3,5-triazine (RDX), and 1,3,5,7-tetranitro-1,3,5,7-tetraazocyclooctane (HMX). Cellular tolerance levels and TNT biotransformation kinetics were examined. Tolerance to TNT varied as cell suspensions aged. Concentrations of RDX or HMX in excess of reported solubility limits produced no observable changes in cell viability. GC/MS analysis of TNT-treated cell media and cell lysates revealed rapid removal of TNT. Within 12 h, less than 1\% of the initial TNT remained in the growth medium. Aminodinitrotoluenes (ADNTs), known metabolites of TNT, accumulated transiently in cell lysates, and to a lesser extent in cell media. ADNT concentrations started to decrease after 3 h. After 12 h, less than 5\% of the initial TNT could be detected as ADNT. Total ADNTs never exceeded 26\% of initial TNT, suggesting that additional biotransformation steps also occurred. No other nitroaromatics were detected. A pseudo-first order rate constant for TNT clearance was calculated, k=0.40 h-1. D. innoxia cell suspension cultures demonstrated virtually complete clearance of TNT and of subsequent ADNT metabolites in less than 12 h. This rapid metabolism of nitroaromatics by the Datura cell suspension system indicates the utility of this system for further molecular and biochemical studies.

}, keywords = {bioremediation, biotransformation, nitroaromatics, phytoremediation}, doi = {10.1007/s11627-999-0072-3}, url = {/files/bibliography/694.pdf}, author = {M.E. Lucero and W. Mueller and Hubstenberger, J. and Phillips, G.C. and M. A. O{\textquoteright}Connell} }