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Primary root and root hair development regulation by OsAUX4 and its participation in the phosphate starvation response
Author(s) -
Ye Rigui,
Wu Yunrong,
Gao Zhenyu,
Chen Hao,
Jia Lixia,
Li Dongming,
Li Xugang,
Qian Qian,
Qi Yanhua
Publication year - 2021
Publication title -
journal of integrative plant biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.734
H-Index - 83
eISSN - 1744-7909
pISSN - 1672-9072
DOI - 10.1111/jipb.13142
Subject(s) - mutant , auxin , meristem , biology , microbiology and biotechnology , root hair , crosstalk , gene , wild type , genetics , physics , optics
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 independent 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 development. The decreased meristem cell division activity 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 negatively 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.