Discovery of Populus trichocarpa small proteins and non-coding RNAs involved in mycorrhizal symbiosis
X. YANG (1), R. Mewalal (2), S. Jawdy (2), P. Vion (3), F. Le Tacon (3), J. Labbé (2), G. Tuskan (2) (1) Oak Ridge National Laboratory, U.S.A.; (2) Oak Ridge National Laboratory, U.S.A.; (3) INRA/Université de Lorraine, Centre INRA de Nancy, France

Symbiotic association between beneficial mycorrhizal fungi and plant roots promotes plant growth and increases stress tolerance. Mycorrhizas can be classified as ectomycorrhiza (EM) or endomycorrhiza such as arbuscular mycorrhiza (AM), which colonize the intercellular spaces of the roots or develops inside the root cells, respectively. It is known that small proteins (SPs) and non-coding RNAs (ncRNAs) from microbes mediate the interaction between plants and fungi. However, our understanding of the role of plant SPs and ncRNAs in mycorrhizal symbiosis is very limited. To test the hypothesis that plant SPs and ncRNAs are involved in mycorrhizal symbiosis, we performed RNA-seq analysis of EM and AM in Populus, a model for tree genomics research and an important crop for bioenergy production, ecosystem services, and forest products industry. Specifically, we sequenced small RNA enriched libraries of Populus trichocarpa roots collected three weeks after inoculation separately with Laccaria bicolor (EM fungus) and Rhizophagus irregularis (AM fungus), with water inoculation as control. Mapping of the RNA-seq reads to the Populus genome revealed approximately 1500 transcripts, with an expression level ≥2 RPKM and a median length of 209 nt. Furthermore, we identified a set of 29 transcripts significantly up- or down-regulated by R. irregularis inoculation and a set of 26 transcripts significantly up- or down-regulated by L. bicolor inoculation as compared with control. Six genes were shared between these two Populus transcript sets, suggesting that AM and EM development involve different sets of small RNAs. We also identified SPs and ncRNAs in the fungus-responsive transcripts.

Abstract Number: P2-55
Session Type: Poster