It has long been thought that growth‐regulating factors（GRFs） gene family members act as transcriptional activators to play important roles in multiple plant developmental processes. However, the recent characterization of Arabidopsis GRF7 showed that it functions as a transcriptional repressor of osmotic stress‐responsive genes. This highlights the complex and diverse mechanisms by which different GRF members use to take action. In this study, the maize（Zea mays L.） GRF10 was functionally characterized to improve this concept. The deduced ZmGRF10 protein retains the N‐terminal QLQ and WRC domains, the characteristic regions as protein‐interacting and DNA‐binding domains, respectively. However,it lacks nearly the entire C‐terminal domain, the regions executing transactivation activity. Consistently, ZmGRF10 protein maintains the ability to interact with GRF‐interacting factors（GIFs） proteins, but lacks transactivation activity.Overexpression of ZmGRF10 in maize led to a reduction in leaf size and plant height through decreasing cell proliferation,whereas the yield‐related traits were not affected. Transcriptome analysis revealed that multiple biological pathways were affected by ZmGRF10 overexpression, including a few transcriptional regulatory genes, which have been demonstrated to have important roles in controlling plant growth and development. We propose that ZmGRF10 aids in fine‐tuning the homeostasis of the GRF‐GIF complex in the regulation of cell proliferation.
Lei WuDengfeng ZhangMing XueJianjun QianYan HeShoucai Wang
Maize（Zea mays） root system architecture（RSA）mediates the key functions of plant anchorage and acquisition of nutrients and water. In this study,a set of 204 recombinant inbred lines（RILs） was derived from the widely adapted Chinese hybrid ZD958（Zheng58 Chang7-2）,genotyped by sequencing（GBS） and evaluated as seedlings for 24 RSA related traits divided into primary,seminal and total root classes. Signi ficant differences between the means of the parental phenotypes were detected for 18 traits,and extensive transgressive segregation in the RIL population was observed for all traits. Moderate to strong relationships among the traits were discovered. A total of 62 quantitative trait loci（QTL） were identi fied that individually explained from1.6% to 11.6%（total root dry weight/total seedling shoot dry weight） of the phenotypic variation. Eighteen,24 and 20 QTL were identi fied for primary,seminal and total root classes of traits,respectively. We found hotspots of 5,3,4 and 12 QTL in maize chromosome bins 2.06,3.02-03,9.02-04,and 9.05-06,respectively,implicating the presence of root gene clusters or pleiotropic effects. These results characterized the phenotypic variation and genetic architecture of seedling RSA in a population derived from a successful maize hybrid.
Weibin SongBaobao WangAndrew L HauckXiaomei DongJieping LiJinsheng Lai
