National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, 110067, India.
Centre of Experimental Medicine and Surgery, Institute of Medical Sciences, Banaras Hindu University, Varanasi, India.
Plant J. 2020 Jan;101(1):87-100. doi: 10.1111/tpj.14520. Epub 2019 Oct 16.
Auxin signaling mediated by various auxin/indole-3-acetic acid (Aux/IAAs) and AUXIN RESPONSE FACTORs (ARFs) regulate lateral root (LR) development by controlling the expression of downstream genes. LATERAL ROOT PRIMORDIUM1 (LRP1), a member of the SHORT INTERNODES/STYLISH (SHI/STY) family, was identified as an auxin-inducible gene. The precise developmental role and molecular regulation of LRP1 in root development remain to be understood. Here we show that LRP1 is expressed in all stages of LR development, besides the primary root. The expression of LRP1 is regulated by histone deacetylation in an auxin-dependent manner. Our genetic interaction studies showed that LRP1 acts downstream of auxin responsive Aux/IAAs-ARFs modules during LR development. We showed that auxin-mediated induction of LRP1 is lost in emerging LRs of slr-1 and arf7arf19 mutants roots. NPA treatment studies showed that LRP1 acts after LR founder cell specification and asymmetric division during LR development. Overexpression of LRP1 (LRP1 OE) showed an increased number of LR primordia (LRP) at stages I, IV and V, resulting in reduced emerged LR density, which suggests that it is involved in LRP development. Interestingly, LRP1-induced expression of YUC4, which is involved in auxin biosynthesis, contributes to the increased accumulation of endogenous auxin in LRP1 OE roots. LRP1 interacts with SHI, STY1, SRS3, SRS6 and SRS7 proteins of the SHI/STY family, indicating their possible redundant role during root development. Our results suggested that auxin and histone deacetylation affect LRP1 expression and it acts downstream of LR forming auxin response modules to negatively regulate LRP development by modulating auxin homeostasis in Arabidopsis thaliana.
生长素信号通过各种生长素/吲哚-3-乙酸（Aux/IAAs）和生长素响应因子（ARFs）介导，通过控制下游基因的表达来调节侧根（LR）的发育。LR 原基 1（LRP1）是 SHORT INTERNODES/STYLISH（SHI/STY）家族的成员，被鉴定为生长素诱导基因。LRP1 在根系发育中的精确发育作用和分子调控仍有待了解。在这里，我们表明 LRP1 在除主根以外的 LR 发育的所有阶段都有表达。LRP1 的表达受生长素依赖性组蛋白去乙酰化的调节。我们的遗传相互作用研究表明，在 LR 发育过程中，LRP1 作为生长素响应 Aux/IAAs-ARFs 模块的下游发挥作用。我们表明，在 slr-1 和 arf7arf19 突变体根的新出现的 LR 中，生长素介导的 LRP1 诱导丧失。NPA 处理研究表明，LRP1 在 LR 起始细胞特化和不对称分裂后在 LR 发育过程中发挥作用。LRP1 的过表达（LRP1 OE）显示在 I、IV 和 V 阶段的 LR 原基（LRP）数量增加，导致出现的 LR 密度降低，这表明它参与了 LRP 的发育。有趣的是，LRP1 诱导的生长素生物合成相关基因 YUC4 的表达有助于增加 LRP1 OE 根中内源性生长素的积累。LRP1 与 SHI/STY 家族的 SHI、STY1、SRS3、SRS6 和 SRS7 蛋白相互作用，表明它们在根系发育过程中可能具有冗余作用。我们的研究结果表明，生长素和组蛋白去乙酰化影响 LRP1 的表达，它作为形成侧根的生长素反应模块的下游发挥作用，通过调节拟南芥中生长素的动态平衡来负调控 LRP 的发育。
