(801.10) Investigating the transcriptomic responses in rice roots during interactions with plant growth-promoting bacteria, Burkholderia unamae

Poster Board Number: A212

Arijit Mukherjee (University of Central Arkansas), John Cook (University of Central Arkansas), Qinqing Yang (University of Central Arkansas), Yasir Rahmatallah (University of Arkansas for Medical Sciences), Galina Glazko (University of Arkansas for Medical Sciences)

Major crops such as rice and maize can benefit from associations with different plant growth-promoting bacteria (PGPB). Studies have shown that these PGPB (e.g., Azospirillum, Burkholderia) promote plant growth primarily via nitrogen fixation and phytohormone secretion. However, our current understanding of the underlying molecular mechanisms involved in these associations is limited. For example, very little is known about the associations between plants and the symbiotic Burkholderia species, B. unamae, at a molecular level. Previously, we set up an experimental system where PGPB such as A. brasilense could colonize rice roots and promote plant growth. In this study, we used the same experimental system and showed that B. unamae could promote growth and colonize rice roots. Next, using RNA sequencing, we identified the transcriptomic responses in rice roots, one day post-inoculation. We identified 1128 differentially expressed genes (DEGs) in rice roots and validated the expression of few genes via RT-PCR. We identified genes involved in the flavonoid biosynthesis, defense, hormone signaling, and photosynthesis differentially expressed. We also identified several genes encoding for transcription factors, protein kinases, and transporters. Comparison of our dataset to existing RNA-seq datasets in rice roots during interactions with other plant-beneficial Burkholderia species (Burkholderia vietnamiensis, Paraburkholderia kururiensis, Paraburkholderia phytofirmans) indicated downregulation of defense genes during these interactions. Finally, we identified 398 DEGs in rice roots during interactions with B. unamae and A. brasilense. Some of these genes are likely to play important roles during these interactions. Overall, our study has identified several promising targets for future genetic studies.

Supported by a grant from NIGMS (P20 GM103429) at National Institutes of Health. Its contents are solely the responsibility of the authors and does not necessarily represent the official views of the NIH.