Submitted to: American Society of Plant Biologists Annual Meeting
Publication Type: Abstract only
Publication Acceptance Date: 9/1/2005
Publication Date: 10/12/2005
Citation: Lucero, M., Barrow, J.R. 2005. Whose genes are we sequencing? Evidence for the presence of multiple genomes in native and regenerated higher plants [abstract]. American Society of Plant Biologists. Plant Genetics 2005 Mechanisms of Genetic Variation. Paper No. 33. Interpretive Summary: No interpretive summary required.
Technical 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 rDNA 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.