ARS | Publication request: Identification of seed borne endopohytes that confer salt tolerance to host plants

Submitted to: Plant Biology Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: March 5, 2007
Publication Date: N/A

Technical 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.