Maitra Majee Susmita, Sharma Eshan, Singh Brinderjit, Khurana Jitendra P
Interdisciplinary Centre for Plant Genomics & Department of Plant Molecular Biology University of Delhi South Campus New Delhi India.
Plant Direct. 2020 Jun 21;4(6):e00234. doi: 10.1002/pld3.234. eCollection 2020 Jun.
The members of early auxin response gene family, , encode negative regulators of auxin signaling but play a central role in auxin-mediated plant development. Here we report the interaction of an Aux/IAA protein, AtIAA14, with Drought-induced-19 (Di19-3) protein and its possible role in auxin signaling. The mutant seedlings develop short hypocotyl, both in light and dark, and are compromised in temperature-induced hypocotyl elongation. The mutant plants accumulate more IAA and also show altered expression of , , and genes involved in auxin biosynthesis and homeostasis, along with many auxin responsive genes like and . seedlings show enhanced root growth inhibition when grown in the medium supplemented with auxin. Nevertheless, number of lateral roots is low in seedlings grown on the basal medium. We have shown that AtIAA14 physically interacts with AtDi19-3 in yeast two-hybrid (Y2H), bimolecular fluorescence complementation, and in vitro pull-down assays. However, the auxin-induced degradation of AtIAA14 in the seedlings was delayed. By expressing in mutant background, it became apparent that both Di19-3 and AtIAA14 work in the same pathway and influence lateral root development in Arabidopsis. Gain-of-function () mutant, like , showed tolerance to abiotic stress in seed germination and cotyledon greening assays. The seedlings showed enhanced sensitivity to ethylene in triple response assay and AgNO, an ethylene inhibitor, caused profuse lateral root formation in the mutant seedlings. These observations suggest that AtDi19-3 interacting with AtIAA14, in all probability, serves as a positive regulator of auxin signaling and also plays a role in some ethylene-mediated responses in Arabidopsis.
This study has demonstrated interaction of auxin responsive Aux/IAA with Drought-induced 19 (Di19) protein and its possible implication in abiotic stress response.
早期生长素响应基因家族的成员，编码生长素信号的负调控因子，但在生长素介导的植物发育中起核心作用。在此，我们报道了一种Aux/IAA蛋白AtIAA14与干旱诱导蛋白19（Di19 - 3）的相互作用及其在生长素信号传导中的可能作用。突变体幼苗在光照和黑暗条件下都发育出短胚轴，并且在温度诱导的胚轴伸长方面存在缺陷。突变体植株积累了更多的生长素，并且还表现出参与生长素生物合成和稳态的、以及基因的表达改变，同时还有许多生长素响应基因如和的表达也发生了变化。幼苗在添加生长素的培养基中生长时，对根生长的抑制增强。然而，在基础培养基上生长的幼苗侧根数量较少。我们已经证明，AtIAA14在酵母双杂交（Y2H）、双分子荧光互补和体外下拉实验中与AtDi19 - 3发生物理相互作用。然而，突变体幼苗中生长素诱导的AtIAA14降解延迟。通过在突变体背景中表达，很明显Di19 - 3和AtIAA14在同一途径中起作用，并影响拟南芥侧根的发育。功能获得型突变体，如，在种子萌发和子叶绿化实验中表现出对非生物胁迫的耐受性。幼苗在三重反应实验中对乙烯表现出增强的敏感性，而乙烯抑制剂硝酸银在突变体幼苗中导致大量侧根形成。这些观察结果表明，AtDi19 - 3与AtIAA1相互作用，很可能作为生长素信号的正调控因子，并且在拟南芥的一些乙烯介导的反应中也起作用。
本研究证明了生长素响应性Aux/IAA与干旱诱导蛋白19（Di19）的相互作用及其在非生物胁迫响应中的可能意义。
