Premium
WD 40‐ REPEAT 5a represses root meristem growth by suppressing auxin synthesis through changes of nitric oxide accumulation in Arabidopsis
Author(s) -
Liu WenCheng,
Zheng SiQiu,
Yu ZhenDong,
Gao Xiang,
Shen Ran,
Lu YingTang
Publication year - 2018
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.13816
Subject(s) - meristem , auxin , mutant , arabidopsis , microbiology and biotechnology , wild type , nitric oxide , arabidopsis thaliana , sodium nitroprusside , biology , lateral root , chemistry , biochemistry , gene , endocrinology
Summary Although nitric oxide ( NO ) is known to regulate root growth, the factor(s) modulating NO during this process have not yet been elucidated. Here, we identified Arabidopsis WD 40‐ REPEAT 5a ( WDR 5a) as a novel factor that functions in root growth by modulating NO accumulation. The wdr5a‐1 mutant accumulated less NO and produced longer roots than the wild type, whereas the WDR 5a overexpression lines had the opposite phenotype. The role of NO was further supported by our observation that the NO donor sodium nitroprusside ( SNP ) and the NO scavenger 2‐(4‐carboxyphenyl)‐4,4,5,5‐tetramethylimidazoline‐1‐oxyl‐3‐oxide ( cPTIO ) rescued the root meristem growth phenotypes of the wdr5a‐1 and WDR 5a overexpression lines, respectively. The regulation of root growth by WDR 5a was found to involve auxin because the auxin levels were similar in SNP ‐treated wdr5a‐1 and wild‐type roots, but higher in untreated wdr5a‐1 roots than in wild‐type roots. In addition, the wdr5a‐1 mutant had higher production and activity levels of the auxin biosynthetic enzyme TRYPTOPHAN AMINOTRANSFERASE OF ARABIDOPSIS 1 ( TAA 1), in contrast to its reduced expression and activity in the WDR 5a overexpression lines, and the increased root meristem growth in wdr5a‐1 was suppressed by treatment with l ‐kynurenine, which inhibits TAA 1, as well as by mutating TAA 1 . WDR 5a therefore functions in root meristem growth by maintaining NO homeostasis, and thus TAA 1‐mediated auxin biosynthesis.