Primary root and root hair development regulation by OsAUX4 and its participation in the phosphate starvation response

• 作者: Rigui Ye Yunrong Wu Zhenyu Gao Hao Chen Lixia Jia Dongming Li Xugang Li Qian Qian Yanhua Qi
• 来源期刊: 植物学报（英文版）
• 年，卷（期）: 2021,（8）
• 所属期刊栏目: Molecular Physiology
• 页码范围: 1555-1567
• 页数: 13页
• 语种: 英文

摘要

Among the five members of AUX1/LAX genes coding for auxin carriers in rice, only OsAUX1 and OsAUX3 have been reported. To understand the function of the other AUX1/LAX genes, two in-dependent alleles of osaux4 mutants, osaux4-1 and osaux4-2, were constructed using the CRISPR/Cas9 editing system. Homozygous osaux4-1 or osaux4-2 exhibited shorter primary root (PR) and longer root hair (RH) compared to the wild-type Dongjin (WT/DJ), and lost response to indoleacetic acid (IAA) treatment. OsAUX4 is intensively expressed in roots and localized on the plasma membrane, suggesting that OsAUX4 might function in the regulation of root develop-ment. The decreased meristem cell division ac-tivity and the downregulated expression of cell cycle genes in root apices of osaux4 mutants supported the hypothesis that OsAUX4 positively regulates PR elongation. OsAUX4 is expressed in RH, and osaux4 mutants showing longer RH compared to WT/DJ implies that OsAUX4 neg-atively regulates RH development. Furthermore, osaux4 mutants are insensitive to Pi starvation (-Pi) and OsAUX4 effects on the -Pi response is associated with altered expression levels of Pi starvation-regulated genes, and auxin distribution/contents. This study revealed that OsAUX4 not only regulates PR and RH development but also plays a regulatory role in crosstalk between auxin and-Pi signaling.