Endophytic fungi associated with shrubs and grasses of the northern Chihuahuan Desert and a potential role in drought tolerance

Title	Endophytic fungi associated with shrubs and grasses of the northern Chihuahuan Desert and a potential role in drought tolerance
Publication Type	Conference Paper
Year of Publication	2004
Authors	Barrow J.R., Aaltonen R.E., Osuna-Avila P., Reyes-Vera I.
Conference Name	Annual Meeting, Canadian Botanical Association
Date Published	June 26-30, 2004
Conference Location	Winnipeg, Manitoba, Canada
ARIS Log Number	163855
Keywords	Chihuahuan Desert, colonization, endophytes, fungi
Abstract	Native grasses and shrubs of the northern Chihuahuan Desert are predominantly colonized by dark septate endophytes. Methods using stains that target fungal chitin and internal lipids with high-magnification, light microscopy and scanning electron microscopy revealed a much greater incidence of colonization than was previously thought. In-vitro-regenerated plants from meristematic stem cells were also found to be colonized with the same fungi observed in plants from native populations. Originally thought to be restricted to roots, they are conspicuously present in meristems, sieve elements, xylem vessels of roots and leaves and in photsynthetic cells and stomata. Differing from pathogens and mycorrhizal fungi that have localized patterns of colonization, they systemically inhabit the entire apoplastic network of below- and aboveground organs. They encapsulate host cell protoplasts and are vertically transmitted by seed. Hyphal networks and biofilms that encapsulate all cells and tissues of micropropagated and native plants prevent their direct exposure to harsh external environments. The intimate nature of the association with all plant cells and organs indicates that these native desert shrubs and grasses function as composite plant-fungus organisms. A potential role in managing basic physiological processes that positively enhance plant survival in arid ecosystems is suggested.