Xanthomonas oryzae-triggered production of rice small RNAs during infection
J. JACOBS (1), G. Reshetnyak (1), F. Auguy (1), A. Perez-Quintero (1), C. Medina (2), R. Koebnik (1), B. Szurek (1), S. Lacombe (3), S. Cunnac (1) (1) IRD-Montpellier, France; (2) INRA, France; (3) IRD-Montpellier, France

Eukaryotic small RNAs (sRNAs) are fundamental regulatory players in gene expression that dictate biological processes such as development, growth and responses to abiotic and biotic stresses. In the cell, sRNAs typically range from 20-24 nucleotides in length, originate from double stranded RNA precursors and are processed into sRNA duplexes by Dicer-like enzymes. sRNAs then associate with RNA-induced gene silencing complexes and target complementary nucleotides to reduce gene expression. The nature of sRNA biogenesis and activity remains heavily underexplored in model systems of important crops such as rice (Oryza sativa) during biotic attack. The bacterium Xanthomonas oryzae causes major foliar diseases of rice. We have identified with high-throughput sRNA sequencing several novel sRNAs that strongly accumulate in rice leaves infected with virulent strains of X. oryzae. These Xanthomonas-induced small RNAs (xisRNAs) have features of regulatory sRNAs and are predicted to target related genes involved in plant immune signaling. Moreover our results demonstrate that X. oryzae manipulates xisRNA production using its virulence arsenal. We will report on our latest efforts to establish that xisRNA promote disease by suppressing their rice target genes. This would represent evidence that, similar to filamentous organism-induced gene silencing (FIGS), bacteria-induced host gene silencing (BIGS) is an integral part of a prokaryotic phytopathogen virulence system.

Abstract Number: P9-263
Session Type: Poster