NAC-乙烯-IAA调控网络在番茄果实成熟中的作用解析

番茄是典型跃变型果实，乙烯是主要的成熟调控因子。我们前期研究发现NAC转录因子深刻地影响着这个成熟过程。CHIP-seq分析发现，NAC4蛋白靶基因在IAA和乙烯激素信号通路中大量富集，据此提出IAA可能在NAC和乙烯调控的果实成熟中发挥特殊作用。本项目拟以NAC4/9和生长素信号因子Aux/IAA 为研究对象，系统分析Aux/IAA家族基因结构，时空表达，明确IAA在成熟中作用；利用外源IAA、乙烯联合处理和高通量测序，分析IAA与乙烯串扰关系；利用过表达和CRISPR技术，解析NAC对乙烯-IAA串扰的作用机制；结合组学技术和DNA-蛋白互作技术研究NAC4/9与IAA响应因子下游靶基因的动态变化，并利用BIFC和Co-IP等技术筛选确定它们的互作蛋白。研究结果将揭示NAC-乙烯-IAA协同调控番茄果实成熟机制，丰富NAC功能，为转录因子介导的激素串扰机制提供新思路和科学依据。

Tomato is a typical climacteric fruit, the ripening of which depends primarily on the control of ethylene. Our preliminary studies indicated that NAC transcription factors have a deeply impact on the ripening. Further CHIP-seq analysis found that the target gene of NAC4 protein is abundant in IAA and ethylene hormone signaling pathways, thus suggesting IAA may play a special role in regulation of fruit ripening based on NAC and ethylene. Therefore, the current project are, NAC4/9 and auxin signaling factor Aux/IAA are to be taken as research objects to systematically analyze the gene structure of Aux/IAA family, temporal and spatial expression, and clarify the role of IAA in maturation. Using exogenous IAA, ethylene combined treatment and high-throughput sequencing, the crosstalk relationship between IAA and ethylene was analyzed. Using overexpression and CRISPR techniques, the mechanism of NAC on ethylene-IAA crosstalk was analyzed. The dynamic changes of target genes downstream of NAC4/9 and IAA response factors were identified through Omics and DNA- protein interaction approaches, and their interaction proteins were screened and determined by BIFC and Co-IP technologies. The results might not only reveal the mechanism of NAC- ethylene -IAA synergistic regulation of tomato fruit ripening, enrich NAC function, but also provide new ideas and scientific basis for transcription factor mediated hormone crosstalk mechanism.