Characteristic Dissection of Xanthomonas oryzae pv. oryzae Responsive MicroRNAs in Rice.

Yanfeng Jia,Wenxue Zhai,Guanghuai Jiang,Chunrong Li,Zhenzhen Liu,Yanyan Wang,Pengcheng Liu,Dongfeng Liu,Quanlin Li

doi:10.3390/ijms21030785

Abstract

MicroRNAs (miRNAs) are crucial player in plant-pathogen interaction. While the evidence has demonstrated that rice miRNAs mediate immune response to pathogens invasion, the roles of miRNAs on Xanthomonas oryzae pv. oryzae (Xoo) attack remain be in place. Herein, we monitored the responsive changes of rice miRNAs at 0, 8, 24 h across Xoo strain PXO86 infection in its compatible rice variety IR24 and incompatible variety IRBB5 by small RNA sequencing, and the genes targeted by miRNAs were also detected via degradome technology. The faithfulness of sequencing data was validated through quantitative real-time stem-loop reverse transcription-polymerase chain reaction assay. Bioinformatic analysis showed that the differentially expressed miRNAs could be divided into three immunity-related clusters, and 80 regulatory units were emerged in infection process, which comprises 29 differentially expressed known miRNAs and 38 cleaved targets. Furthermore, the miRNA presumptive function of separate immunity cluster in rice-Xoo interplay was confirmed through overexpressing osa-miR164a, osa-miR167d and osa-miR159b, and the disruption of regulatory units, osa-miR164a/OsNAC60, osa-miR167d-5p/OsWD40-174 and osa-miR159b/OsMYBGA, OsLRR-RLK2, OsMPK20-4, may reset rice defense response to Xoo infestation in a controllable manner. These findings provide new insights into the complex roles of characteristic miRNAs and their targets in rice-Xoo interactions.

Highlights

Plants often answer biotic stress with growth inhibition and yield loss
We examined the transcriptional changes of Xanthomonas oryzae pv. oryzae (Xoo)-responsive miRNAs at three time points during early infection stage and analyzed the Xoo-responsive genes regulated by miRNAs in the bacterial blight-susceptible variety IR24 and bacterial blight-resistant variety IRBB5, respectively
We found that 43 known miRNAs were differentially expressed (DE) in infected IRBB5 plants relative to IR24 plants, and were categorized into three immunity related groups according to their expression characteristic in the both rice varieties

Summary

Introduction

Plants often answer biotic stress with growth inhibition and yield loss. Rice (Oryza sativa L.) supplies 25% of the total caloric intake for human, its production faces severely threat from pathogens, such as fungal, bacterial and viral invasion. Oryzae (Xoo) infection, and has become an ideal pathosystem to characterize the interaction between plant and bacterial pathogens [1]. Several independent studies have monitored the expression alterations of miRNAs in virally-infected rice plants by small RNA profiling and/or degradome sequencing [22,23]. In accordance with the research progress of miRNAs in rice and the aforementioned pathogens interaction, there are few published evidences describing Xoo-responsive miRNAs. Two recent small RNA sequencing data showed that rice miRNAs are responsive to Xoo utilizing dynamic and coordinated transcriptional changes and may participate in Xa3/Xa26 mediated defense response, respectively [28,29]. The enhancive osa-miR169o boosted the pathogenicity of Xoo strains [32]

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Discussion

Conclusion