Cai Hanyang, Chai Mengnan, Chen Fangqian, Huang Youmei, Zhang Man, He Qing, Liu Liping, Yan Maokai, Qin Yuan
Key Laboratory of Genetics, Breeding and Multiple Utilization of Crops, Ministry of Education, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, College of Agriculture, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.
State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi Key Lab of Sugarcane Biology, College of Agriculture, Guangxi University, Nanning, 530004, China.
New Phytol. 2021 Jan;229(1):414-428. doi: 10.1111/nph.16840. Epub 2020 Sep 1.
Inflorescence architecture critically influences plant reproductive success and crop yield, and it reflects the activity of the inflorescence meristem and pedicel length. In Arabidopsis thaliana, the ERECTA (ER) signaling pathway and the SWR1 chromatin remodeling complex jointly regulate inflorescence architecture by promoting the expression of the PACLOBUTRAZOL RESISTANCE (PRE) gene family. However, how PREs regulate inflorescence architecture remains unclear. RNA-sequencing and chromatin immunoprecipitation coupled with quantitative PCR analyses were performed. Genetic interactions between HOMOLOG OF BEE2 INTERACTING WITH IBH1 (HBI1) and the SWR1-ER-MPK6 pathway in the control of inflorescence architecture were further studied. The present findings support that HBI1 functions downstream of PREs in the SWR1 and ER pathways to regulate inflorescence architecture by promoting pedicel elongation. Specifically, it binds to the promoters of the brassinosteroid (BR) biosynthesis gene CYP85A2 and a series of auxin-related genes, including auxin response factor ARF3, and promotes their expression. In turn, ARF3 can also bind to auxin signaling genes as well as CYP85A2 to activate their expression and promote pedicel elongation. Our study provides evidence that inflorescence architecture regulation by SWR1 and ER involves the HBI1 regulatory hub and its activation of both the BR and auxin hormone pathways.
花序结构对植物繁殖成功率和作物产量至关重要，它反映了花序分生组织的活性和花梗长度。在拟南芥中，ERECTA（ER）信号通路和SWR1染色质重塑复合体通过促进多效唑抗性（PRE）基因家族的表达共同调节花序结构。然而，PREs如何调节花序结构仍不清楚。进行了RNA测序和染色质免疫沉淀结合定量PCR分析。进一步研究了与IBH1相互作用的BEE2同源物（HBI1）与SWR1-ER-MPK6途径在花序结构控制中的遗传相互作用。目前的研究结果支持，HBI1在SWR1和ER途径中PREs的下游发挥作用，通过促进花梗伸长来调节花序结构。具体而言，它与油菜素内酯（BR）生物合成基因CYP85A2以及一系列生长素相关基因（包括生长素响应因子ARF3）的启动子结合，并促进它们的表达。反过来，ARF3也可以与生长素信号基因以及CYP85A2结合，激活它们的表达并促进花梗伸长。我们的研究提供了证据，表明SWR1和ER对花序结构的调节涉及HBI1调控枢纽及其对BR和生长素激素途径的激活。
