Li Jieping, Chen Fanjun, Li Yanqing, Li Pengcheng, Wang Yuanqing, Mi Guohua, Yuan Lixing
Key Laboratory of Plant-Soil Interaction, MOE, Department of Plant Nutrition, College Resources and Environmental Sciences, China Agricultural University, Beijing, China.
Key Laboratory of Plant Stress Biology, State Key Laboratory of Cotton Biology, Department of Plant Science, School of Life Sciences, Henan University, Kaifeng, China.
Front Plant Sci. 2019 Jul 4;10:820. doi: 10.3389/fpls.2019.00820. eCollection 2019.
In maize, shoot-borne roots dominate the whole root system and play essential roles in water and nutrient acquisition and lodging tolerance. Shoot-borne roots initiate at shoot nodes, including crown roots from the belowground nodes and brace roots from aboveground nodes. In contrast to crown roots, few genes for brace roots development have been identified. Here, we characterized a maize AP2/ERF transcription factor, ZmRAP2.7, to be involved in brace roots development. expressed in all types of roots, and the encoded protein localized in the nucleus with transcriptional activation activity. A maize transposon insert mutant defective in expression revealed a decreased number of brace roots but not crown roots. Maize mutant, which showed an elevated expression of , however, revealed an increased number of brace roots. The -based association analysis in a maize panel further identified a SNP marker at the fifth exon of gene to be associated with number of brace roots. These results uncovered a function of ZmRAP2.7 in brace roots development and provided the valuable gene and allele for genetic improvement of maize root systems.
在玉米中，气生根主导着整个根系，并在水分和养分获取以及抗倒伏能力方面发挥着重要作用。气生根在地上节上起始，包括地下节上的冠根和地上节上的支持根。与冠根相比，已鉴定出的控制支持根发育的基因很少。在这里，我们鉴定了一个玉米AP2/ERF转录因子ZmRAP2.7参与支持根的发育。它在所有类型的根中均有表达，并且编码的蛋白质定位于细胞核中，具有转录激活活性。一个在ZmRAP2.7表达上存在缺陷的玉米转座子插入突变体显示支持根数量减少，但冠根数量未减少。然而，一个ZmRAP2.7表达升高的玉米过表达突变体显示支持根数量增加。在一个玉米群体中基于ZmRAP2.7的关联分析进一步确定该基因第五外显子上的一个SNP标记与支持根数量相关。这些结果揭示了ZmRAP2.7在支持根发育中的功能，并为玉米根系的遗传改良提供了有价值的基因和等位基因。
