1. Overexpression of miR169o, an Overlapping MicroRNA in Response to Both Nitrogen Limitation and Bacterial Infection, Promotes Nitrogen Use Efficiency and Susceptibility to Bacterial Blight in Rice
- Author
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Chao Yu, Jichun Wang, Fang Tian, Steven J. Rothstein, Yong-Mei Bi, Chen Yutong, Cao Yaqian, Xueping Zhou, Huamin Chen, Fenghuan Yang, and Chenyang He
- Subjects
0301 basic medicine ,Xanthomonas ,Nitrogen ,Physiology ,Gene Expression ,Plant Science ,Biology ,Plant disease resistance ,Microbiology ,03 medical and health sciences ,Xanthomonas oryzae ,Gene Expression Regulation, Plant ,Gene expression ,Gene ,Disease Resistance ,Plant Diseases ,Regulation of gene expression ,Oryza sativa ,Nitrogen deficiency ,Wild type ,food and beverages ,Oryza ,Cell Biology ,General Medicine ,biology.organism_classification ,MicroRNAs ,030104 developmental biology ,RNA, Plant - Abstract
Limiting nitrogen (N) supply contributes to improved resistance to bacterial blight (BB) caused by Xanthomonas oryzae pv. oryzae (Xoo) in susceptible rice (Oryza sativa). To understand the regulatory roles of microRNAs (miRNAs) in this phenomenon, 63 differentially expressed overlapping miRNAs in response to Xoo infection and N limitation stress in rice were identified through deep RNA sequencing and stem-loop quantitative real-time PCR. Among these, miR169o was further assessed as a typical overlapping miRNA through the overexpression of the miR169o primary gene. Osa-miR169o-OX plants were taller, and had more biomass accumulation with significantly increased nitrate and total amino acid contents in roots than the wild type (WT). Transcript level assays showed that under different N supply conditions, miR169o oppositely regulated NRT2, and this is reduced under normal N supply conditions but remarkably induced under N-limiting stress. On the other hand, osa-miR169o-OX plants also displayed increased disease lesion lengths and reduced transcriptional levels of defense gene (PR1b, PR10a, PR10b and PAL) compared with the WT after inoculation with Xoo. In addition, miR169o impeded Xoo-mediated NRT transcription. Therefore, the overlapping miR169o contributes to increase N use efficiency and negatively regulates the resistance to BB in rice. Consistently, transient expression of NF-YA genes in rice protoplasts promoted the transcripts of PR genes and NRT2 genes, while it reduced the transcripts of NRT1 genes. Our results provide novel and additional insights into the co ordinated regulatory mechanisms of cross-talk between Xoo infection and N deficiency responses in rice.
- Published
- 2018