ARF7 and ARF19 regulate lateral root formation via direct activation of LBD/ASL genes in Arabidopsis
ARF7 and ARF19 regulate lateral root formation via direct activation of LBD/ASL genes in Arabidopsis
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DOI：
10.1105/tpc.106.047761
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发表时间：
2007-01-01
期刊：
影响因子：
11.6
通讯作者：
Tasaka, Masao
中科院分区：
文献类型：
--
作者：
Okushima, Yoko;Fukaki, Hidehiro;Tasaka, Masao
拟南芥侧根的形成受两个相关的生长素反应因子ARF 7和ARF 19的调控，这两个因子是早期生长素反应基因的转录激活因子。arf 7和arf 19双敲除突变体在侧根形成中严重受损。在携带可诱导形式的ARF 7和ARF 19的arf 7和arf 19转基因植物中的靶基因分析显示，ARF 7和ARF 19直接调节根中生长素介导的LATERAL ORGAN BOUNDARIES-DOMAIN 16/ASYMMETRIC LEAVES 2-LIKE 18（LBD 16/ASL 18）和/或LBD 29/ASL 16的转录。LBD 16/ASL 18和LBD 29/ASL 16的过表达在不存在ARF 7和ARF 19的情况下诱导侧根形成。这些LBD/ASL蛋白定位于细胞核中，并且LBD 16/ASL 18活性的显性抑制抑制侧根形成和生长素介导的基因表达，强烈表明这些LBD/ASL在侧根形成中的ARF 7和ARF 19依赖的生长素信号传导的下游起作用。我们的研究结果表明，在拟南芥中，ARF通过直接激活LBD/ASLs来调节侧根的形成。
Lateral root formation in Arabidopsis thaliana is regulated by two related AUXIN RESPONSE FACTORs, ARF7 and ARF19, which are transcriptional activators of early auxin response genes. The arf7 arf19 double knockout mutant is severely impaired in lateral root formation. Target-gene analysis in arf7 arf19 transgenic plants harboring inducible forms of ARF7 and ARF19 revealed that ARF7 and ARF19 directly regulate the auxin-mediated transcription of LATERAL ORGAN BOUNDARIES-DOMAIN16/ASYMMETRIC LEAVES2-LIKE18 (LBD16/ASL18) and/or LBD29/ASL16 in roots. Overexpression of LBD16/ASL18 and LBD29/ASL16 induces lateral root formation in the absence of ARF7 and ARF19. These LBD/ASL proteins are localized in the nucleus, and dominant repression of LBD16/ASL18 activity inhibits lateral root formation and auxin-mediated gene expression, strongly suggesting that these LBD/ASLs function downstream of ARF7- and ARF19-dependent auxin signaling in lateral root formation. Our results reveal that ARFs regulate lateral root formation via direct activation of LBD/ASLs in Arabidopsis.