X oo -responsive transcriptome reveals the role of the circular RNA133 in disease resistance by regulating expression of OsARAB in rice

Upon Xanthomonas oryzae pv. oryzae ( Xoo ) infection of rice leaves, the invasion induces systematic expression changes for both the coding genes and the non-coding genes, allowing the plant to make corresponding responses. However, the roles of circular RNAs (circRNAs) in rice defending against Xoo remain largely unknown. To address this question, we conducted a whole-transcriptomic analysis to systematically screen the differentially expressed (DE) mRNAs and non-coding RNAs (ncRNAs) in rice responding to Xoo infection. Our results revealed a total of 4076 DE mRNAs, 89 DE long non-coding RNAs (lncRNAs), 82 DE microRNAs (miRNAs), and 14 DE circRNAs identified from Xoo -infected rice plants at 48 h post inoculation. Three circRNAs (ciR52, ciR298, and ciR133) were found to be able to form circular RNAs, and their expression was induced by Xoo infection. ciR133 was found to repress the expression of its parental gene OsARAB (putative arabinofuranosidase gene) during Xoo infection. Overexpression of ciR133 and mutation of OsARAB enhanced rice resistance against Xoo , without compromising main agronomic traits. Our data suggest that circRNAs are associated with rice response to Xoo infection, providing a potential strategy for breeding Xoo -resistant rice plants by manipulating ciR133 and OsARAB .