miR156和miR172及其靶基因间互作对玉米生长发育影响与分子调控网络解析

MicroRNAs是植物重要的表达调控因子，参与植物的各类代谢活动、各个发育时期和抗逆响应的调控。miR156被证明在植株发育阶段转变、叶片形成与发育、产量形成、栽培驯化和株型等生长活动的调控网络中处于关键位置；而miR172参与植物的开花、花器性别决定和衰老等过程的调控。miR156-SPLs和miR172-AP2在拟南芥中的调控机制和两个途径间的调控网络已经比较清晰，且各靶基因的功能也得到了验证，然而单子叶植物玉米中这两个途径的调控网络尚不清楚，并且相关基因的突变体具有与双子叶植物不同的表型变异。本研究将利用STTM和CRISPR/Cas9技术分别对玉米miR156、miR172及其靶基因功能和调控机制进行研究，可为高产玉米提供理论支持；同时本研究中可创造大量已知基因编辑的转基因系，为玉米优异自交系的选育提供优良种质。

MicroRNA (miRNA) plays a vital role in plant gene regulation, involving various metabolisms, developmental phase changes, and responses to various stresses in maize and other crops. In plants, the miR156 family has been identified to play a key role in plant developmental phase transition, leaf patterning and development, yield determining, domestication, and plant architecture. In contrast, the miR172 family are involving in plant flowering, floral sex determination, and senescence. Especially, miR156-SPLs and miR172-AP2 interactions determine the transition of plant vegetative to reproductive phase and flowering that is important in crop production. Although the target gene function and the regulatory network of miR156-SPLs and miR172-AP2 pathways have been well studied in Arabidopsis, the associated mechanisms in monocot plants, including maize and rice, were not very clear. Moreover, the identified mutants of miR156-SPLs and miR172-AP2 in maize and rice exhibited different phenotypes to their homologous genes in dicots. Interestingly, the two miRNA pathways might also determine maize grain-yield and plant architecture. In the present study, new technologies short tandem target mimic (STTM) and CRISPR/Cas9 will be applied for blocking miRNA expression and knocking out the targeted genes to dissect the regulatory network of the two key miRNA families and their target genes. Studies on the regulatory mechanism of the two miRNA pathways in maize will certainly benefit yield improvement and creating new elite germplasm for maize breeding.