ZmbZIP4 contributes to stress resistance in maize by regulating ABA synthesis and root development

First author: Haizhen Ma; Affiliations: Shandong university (山东大学): Jinan, China

Corresponding author: Juren Zhang

In plants, bZIP (basic leucine zipper) transcription factors regulate diverse processes such as development and stress responses. However, few of these transcription factors have been functionally characterized in maize (Zea mays). In this study, we characterized the bZIP transcription factor gene ZmbZIP4 from maize. ZmbZIP4 was differentially expressed in various organs of maize and was induced by high salinity, drought treatment, heat, cold and abscisic acid in seedlings. A transactivation assay in yeast demonstrated that ZmbZIP4 functioned as a transcriptional activator. The genome-wide screen for ZmbZIP4 targets by immunoprecipitation sequencing revealed that ZmbZIP4 could positively regulate a number of stress response genes, such as ZmLEA2, ZmRD20, ZmRD21, ZmRab18, ZmNHX3, ZmGEA6, and ZmERD, and some abscisic acid (ABA) synthesis-related genes, including NCED, ABA1, AAO3, and LOS5. In addition, ZmbZIP4 targets some root development-related genes, including ZmLRP1, ZmSCR, ZmIAA8, ZmIAA14, ZmARF2 and ZmARF3, and overexpression of ZmbZIP4 resulted in in an increased number of lateral roots, longer primary roots, and an improved root system. Increased ABA synthesis by overexpression of ZmbZIP4 can also increase the plant's ability to resist the abiotic stress. Thus, ZmbZIP4 is a positive regulator of plant abiotic stress responses and is involved in root development in maize.

在植物中，碱性亮氨酸拉链bZIP转录因子参与植物发育与胁迫响应。然而，这些转录因子在玉米中的功能研究还很少。本文鉴定了玉米中bZIP转录因子ZmbZIP4的功能。ZmbZIP4基因在玉米不同器官中存在差异表达，并且受到高盐、干旱、高温、低温以及脱落酸处理的诱导。在酵母中的转录激活试验显示ZmbZIP4蛋白发挥转录激活的作用。通过对ZmbZIP4靶向基因的免疫共沉淀测序显示ZmbZIP4可以正向调控一系列的ABA合成相关基因，包括NCED、ABA1、AAO3和LOS5基因。另外，ZmbZIP4还靶向了一些根发育相关的基因，包括ZmLRP1、ZmSCR、ZmIAA8、ZmIAA14、ZmARF2和ZmARF3基因，并且过表达ZmbZIP4基因会导致侧根数量的增加及主根的增长。由过表达ZmbZIP4所导致的ABA生物合成还会增强植物抵抗非生物胁迫的能力。因此，本文的研究显示玉米中ZmbZIP4蛋白是植物非生物胁迫响应的正向调控子，并且参与了根的发育。

通讯：张举仁 (http://www.lifesci.sdu.edu.cn/info/1062/1651.htm)

个人简介：1975-1978年，甘肃农业大学，农学学士；1978-1982年，兰州大学，细胞生物学硕士；1982-1985年，兰州大学，细胞生物学博士。

研究方向：植物基因工程和细胞工程；玉米功能基因组研究。

doi: https://doi.org/10.1104/pp.18.00436

Journal: Plant Physiology

First Published: 20 August, 2018

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