WD40-REPEAT 5a represses root meristem growth by suppressing auxin synthesis through changes of nitric oxide accumulation in Arabidopsis
WD40-REPEAT 5a represses root meristem growth by suppressing auxin synthesis through changes of nitric oxide accumulation in Arabidopsis
复制标题
WD40-REPEAT 5a 通过改变拟南芥中一氧化氮积累来抑制生长素合成，从而抑制根分生组织生长
DOI：
10.1111/tpj.13816
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发表时间：
2018-03-01
期刊：
影响因子：
7.2
通讯作者：
Lu, Ying-Tang
中科院分区：
文献类型：
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作者：
Liu, Wen-Cheng;Zheng, Si-Qiu;Lu, Ying-Tang
尽管已知一氧化氮(NO)调节根的生长，但调控NO的因子(S)在这一过程中的作用尚未阐明。在此，我们发现拟南芥WD40-Repeat 5a(WDR5a)是一种通过调节NO积累而在根生长中发挥作用的新因子。与野生型相比，wdr5a-1突变体积累的NO较少，生根较长，而wdr5a高表达系的表型与野生型相反。我们观察到NO供体硝普钠(SNP)和NO清除剂2-(4-carboxyphenyl)-4，4，5，5-tetramethylimidazoline-1-oxyl-3-oxide(CPTIO)分别拯救了Wdr5a-1和WDR5a过表达系的根分生组织生长表型，进一步支持了NO的作用。WDR5a对根生长的调控涉及生长素，因为SNP处理的wdr5a-1和野生型根的生长素水平相似，但未处理的wdr5a-1根的生长素水平高于野生型根。此外，突变体wdr5a-1具有较高的生长素生物合成酶阿拉伯色氨酸转氨酶(Taa1)的产量和活性水平，而wdr5a-1高表达系中生长素生物合成酶taa1的表达和活性降低，并且抑制taa1的L犬尿氨酸处理和突变taa1抑制了wdr5a-1根分生组织的生长。因此，WDR5a在根分生组织的生长中发挥作用，不维持动态平衡，因此TAA1介导的生长素生物合成。
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 WD40-REPEAT 5a (WDR5a) 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 WDR5a 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 WDR5a overexpression lines, respectively. The regulation of root growth by WDR5a 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 ARABIDOPSIS1 (TAA1), in contrast to its reduced expression and activity in the WDR5a overexpression lines, and the increased root meristem growth in wdr5a-1 was suppressed by treatment with L-kynurenine, which inhibits TAA1, as well as by mutating TAA1. WDR5a therefore functions in root meristem growth by maintaining NO homeostasis, and thus TAA1-mediated auxin biosynthesis.