The OsmiR396–Os GRF 8–OsF3H‐flavonoid pathway mediates resistance to the brown planthopper in rice ( Oryza sativa )

作者：Zhengyan Dai, Jiang Tan, Cong Zhou, Xiaofang Yang, Fang� Yang, Shijuan Zhang, Shichen Sun, Xuexia Miao, Zhenying Shi · 发表于：Plant Biotechnology Journal · 年份：2019 · DOI：10.1111/pbi.13091 · 被引用次数：227 · 研究领域：Plant Molecular Biology Research、Plant Stress Responses and Tolerance、Plant Parasitism and Resistance

Multi-functional microRNAs (miRNAs) are emerging as key modulators of plant-pathogen interactions. Although the involvement of some miRNAs in plant-insect interactions has been revealed, the underlying mechanisms are still elusive. The brown planthopper (BPH) is the most notorious rice (Oryza sativa)-specific insect that causes severe yield losses each year and requires urgent biological control. To reveal the miRNAs involved in rice-BPH interactions, we performed miRNA sequencing and identified BPH-responsive OsmiR396. Sequestering OsmiR396 by overexpressing target mimicry (MIM396) in three genetic backgrounds indicated that OsmiR396 negatively regulated BPH resistance. Overexpression of one BPH-responsive target gene of OsmiR396, growth regulating factor 8 (OsGRF8), showed resistance to BPH. Furthermore, the flavonoid contents increased in both the OsmiR396-sequestered and the OsGRF8 overexpressing plants. By analysing 39 natural rice varieties, the elevated flavonoid contents were found to correlate with enhanced BPH resistance. Artificial applications of flavonoids to wild type (WT) plants also increased resistance to BPH. A BPH-responsive flavanone 3-hydroxylase (OsF3H) gene in the flavonoid biosynthetic pathway was proved to be directly regulated by OsGRF8. A genetic functional analysis of OsF3H revealed its positive role in mediating both the flavonoid contents and BPH resistance. And analysis of the genetic correlation between OsmiR396 and OsF3H showed that down-regul...