miR5048-TaMAPK3模块在小麦穗和籽粒生长发育中的功能和分子机制研究

穗粒数和籽粒大小是决定小麦品质和产量的两个重要发育性状，了解其调控基因的功能及分子机制可为优质高产育种提供科学依据。项目组前期发现麦类特有miR5048在小麦营养器官高表达，在幼穗和籽粒表达量极低；其靶基因TaMAPK3表达模式与之相反；小麦miR5048活性影响穗粒数和粒重；但miR5048-TaMAPK3模块的功能及作用机制未知。本项目拟在前期工作基础上，创制miR5048和TaMAPK3过表达株系和功能缺失突变体；研究miR5048和TaMAPK3在小麦穗和籽粒生长发育中的功能；利用小麦自然群体研究TaMAPK3等位基因变异与产量性状的相关性；采用Co-IP、酵母双杂和BiFC技术鉴定和验证TaMAPK3的互作蛋白；分析miR5048过表达和活性抑制株系的转录组和代谢组变化。本项目旨在揭示miR5048-TaMAPK3模块的功能及分子机制，为小麦分子育种提供理论依据和新基因资源｡

The normal development of spike and seed are prerequisite of wheat grain yield. The functional identification of key genes in controlling spike and seed development and uncovering the molecular mechanism underlying can provide with theoretical basis and valuable new gene resources for molecular breeding of wheat with high yield and good quality..In our previous research, it was found that cereal-specific miR5048 was highly expressed in vegetative organs but very low in young spike and developing grains; on the contrary, its target gene TaMAPK3 was highly expressed in the transition stage from vegetative to reproductive growth. The transient silence or overexpression of miR5048 affected the number and weight of grains per spike. However, the function and mechanism of miR5048-TaMAPK3 module in spike and grain development were unknown. Based on the previous study, we plan to create miR5048 and TaMAPK3 overexpression lines and loss of function mutants in order to study the effect of miR5048 and TaMAPK3 expression on the growth and development of wheat spike, spikelet and grain, and to investigate the functions of miR5048-TaMAPK3 module in the growth and development of wheat spike and grain. The correlations between Allele variation of TaMAPK3 homoelogs, TaMAPK3-6A,-6B and -6D, and yield-traits will be investigated by using natural wheat population. Moreover, the interaction proteins of TaMAPK3 will be identified through Co-IP, yeast two hybrid and BiFC techniques, and the transcriptome and the metabolitome of miR5048 overexpression lines and miR5048 mutant will be analyzed. The purpose of this project is to explore the function, molecular mechanism and regulatory network of miR5048-TaMAPK3 module in the growth and development of wheat spike and grain, and to functionally identify high-quality and -yield related new genes, so as to provide with theoretical basis and valuable new gene resources for molecular breeding of wheat with high-yield and -quality.