Abstract：
The brown planthopper (BPH) is the most destructive pest of rice. The MYB transcription factors are vital for rice immunity, but most are activators. Although MYB22 positively regulates rice resistance to BPH and has an EAR motif associated with active repression, it remains unclear whether it is a transcriptional repressor affecting rice-BPH interaction. Genetic analyses revealed that MYB22 regulates rice resistance to BPH via its EAR motif. Several biochemical experiments (e.g. transient transcription assay, Y2H, LCA, and BiFC) indicated that MYB22 is a transcriptional repressor that interacts with the corepressor TOPLESS via its EAR motif and recruits HDAC1 to form a tripartite complex. Flavonoid-3\'-hydroxylase (F3\'H) is a flavonoid biosynthesis pathway-related gene that negatively regulates rice resistance to BPH. Based on a bioinformatics analysis and the results of EMSA and transient transcription assays, MYB22 can bind directly to the F3\'H promoter and repress gene expression along with TOPLESS and HDAC1. We revealed a transcriptional regulatory mechanism influencing the rice-BPH interaction that differs from previously reported mechanisms. Specifically, MYB22-TOPLESS-HDAC1 is a novel transcriptional repressor complex with components that synergistically and positively regulate rice resistance to BPH through the transcriptional repression of F3\'H.
摘要：
褐飞虱(BPH)是水稻危害最大的害虫。MYB转录因子对水稻免疫至关重要,但大多数是激活剂。尽管MYB22积极调节水稻对BPH的抗性，并且具有与主动抑制相关的EAR基序，尚不清楚它是否是影响水稻-BPH相互作用的转录抑制因子。遗传分析表明，MYB22通过其EAR基序调节水稻对BPH的抗性。几个生化实验（例如瞬时转录测定，Y2H,LCA,和BiFC）表明MYB22是一种转录阻遏物，可通过其EAR基序与辅助阻遏物TOPLESS相互作用，并招募HDAC1形成三方复合物。类黄酮-3'-羟化酶（F3'H）是一种类黄酮生物合成途径相关基因，负调节水稻对BPH的抗性。基于生物信息学分析以及EMSA和瞬时转录测定的结果，MYB22可与F3\'H启动子直接结合，并与TOPLESS和HDAC1一起抑制基因表达。我们揭示了一种影响水稻-BPH相互作用的转录调控机制，该机制不同于先前报道的机制。具体来说,MYB22-TOPLESS-HDAC1是一种新型的转录抑制复合物，其成分可以通过F3\'H的转录抑制来协同和积极调节水稻对BPH的抗性。
