Fungal genomes that influence basic physiological processes that enhance survival of black grama and fourwing saltbush in arid Southwestern rangelands

TitleFungal genomes that influence basic physiological processes that enhance survival of black grama and fourwing saltbush in arid Southwestern rangelands
Publication TypeConference Paper
Year of Publication2004
AuthorsBarrow J.R., Osuna-Avila P., Reyes-Vera I.
Conference Name13th Wildland Shrub Symposium, Shrubland Dynamics: Fire and Water
Date PublishedAugust 10-12, 20
Conference LocationLubbock, TX
ARIS Log Number163857
Keywordsassociations, composite, fungi, manipulation, native plants
AbstractSymbiotic fungi are generally known to enhance photosynthetic rates and drought tolerance in host plants, but mechanisms are currently unresolved. Shrubs and grasses of southwestern deserts are colonized by symbiotic fungi that cannot be removed by conventional sterilization methods. These fungi were extensively studied in native plants over a wide range of locations and environmental conditions. Fungi associated with native plants were also found to be intrinsically integrated with cells, tissues and regenerated plant cultures. Native grasses and shrubs were found to be composite plant-fungus organisms comprised of at least two fungal species. It is suggested that these inherent associations modify their hosts at the genetic, cell and physiological levels and positively enhance ecological fitness. Colonization of photosynthetic cells, encapsulation of chloroplasts and accumulation of lipids provided evidence for host modification and performance. Carbon management is suggested by the substantial quantities of high energy lipids that are stored and transported in sieve elements. Lipids converted to biofilms protected cells, tissues, roots and leaves from direct exposure to the external environment. Unique associations with xylem vessels suggested that fungi may actively transport water during drought. Colonization of the stomatal complex indicated a role in regulating gas exchange, photosynthesis and water loss by transpiration. We suggest that symbiotic fungi have a multifunctional role of enhancing drought tolerance of native desert plants. Improvement of native plants by conventional breeding or gene transfers is expensive and time-consuming. Manipulation of fungi rather than plants may provide a more efficient alternative for their improvement.