State Key Laboratory of Plant Physiology and Biochemistry, Engineering Research Center of Plant Growth Regulator, Ministry of Education & College of Agronomy and Biotechnology, China Agricultural University, No.2 Yuanmingyuan West Road, Haidian, Beijing 100193, China.
North China Key Laboratory for Crop Germplasm Resources, Ministry of Education, State Key Laboratory of North China Crop Improvement and Regulation & College of Agronomy, Hebei Agricultural University, Baoding, Hebei 071001, China.
J Exp Bot. 2023 Aug 17;74(15):4503-4519. doi: 10.1093/jxb/erad178.
The lengths of the basal internodes is an important factor for lodging resistance of maize (Zea mays). In this study, foliar application of coronatine (COR) to 10 cultivars at the V8 growth stage had different suppression effects on the length of the eighth internode, with three being categorized as strong-inhibition cultivars (SC), five as moderate (MC), and two as weak (WC). RNA-sequencing of the eighth internode of the cultivars revealed a total of 7895 internode elongation-regulating genes, including 777 transcription factors (TFs). Genes related to the hormones cytokinin, gibberellin, auxin, and ethylene in the SC group were significantly down-regulated compared to WC, and more cell-cycle regulatory factors and cell wall-related genes showed significant changes, which severely inhibited internode elongation. In addition, we used EMSAs to explore the direct regulatory relationship between two important TFs, ZmABI7 and ZmMYB117, which regulate the cell cycle and cell wall modification by directly binding to the promoters of their target genes ZmCYC1, ZmCYC3, ZmCYC7, and ZmCPP1. The transcriptome reported in this study will provide a useful resource for studying maize internode development, with potential use for targeted genetic control of internode length to improve the lodging resistance of maize.
玉米节间长度是抗倒伏的一个重要因素。本研究在玉米 V8 期叶面喷施冠菌素（COR），对 10 个品种的第八节间长度的抑制作用不同，其中 3 个品种为强抑制（SC），5 个为中抑制（MC），2 个为弱抑制（WC）。对 SC 品种第八节间进行 RNA 测序，共鉴定到 7895 个调控节间伸长的基因，包括 777 个转录因子（TFs）。与 WC 相比，SC 组中与细胞分裂素、赤霉素、生长素和乙烯激素相关的基因显著下调，更多的细胞周期调控因子和细胞壁相关基因发生显著变化，严重抑制节间伸长。此外，我们还通过 EMSA 实验探讨了两个重要的 TF（ZmABI7 和 ZmMYB117）之间的直接调控关系，它们通过直接结合其靶基因 ZmCYC1、ZmCYC3、ZmCYC7 和 ZmCPP1 的启动子，调控细胞周期和细胞壁修饰。本研究中转录组数据将为玉米节间发育的研究提供有用的资源，有望用于目标基因遗传控制节间长度，从而提高玉米的抗倒伏能力。
