PDF(Pubmed)
Abstract：
Ultraviolet-B (UV-B) radiation is one of the important environmental factors limiting plant growth. Both abscisic acid (ABA) and microtubules have been previously reported to be involved in plant response to UV-B. However, whether there is a potential link between ABA and microtubules and the consequent signal transduction mechanism underlying plant response to UV-B radiation remains largely unclear. Here, by using sad2-2 mutant plants (sensitive to ABA and drought) and exogenous application of ABA, we saw that ABA strengthens the adaptive response to UV-B stress in Arabidopsis thaliana (A. thaliana). The abnormal swelling root tips of ABA-deficient aba3 mutants demonstrated that ABA deficiency aggravated the growth retardation imposed by UV-B radiation. In addition, the cortical microtubule arrays of the transition zones of the roots were examined in the aba3 and sad2-2 mutants with or without UV-B radiation. The observation revealed that UV-B remodels cortical microtubules, and high endogenous ABA can stabilize the microtubules and reduce their UV-B-induced reorganization. To further confirm the role of ABA on microtubule arrays, root growth and cortical microtubules were evaluated after exogenous ABA, taxol, and oryzalin feeding. The results suggested that ABA can promote root elongation by stabilizing the transverse cortical microtubules under UV-B stress conditions. We thus uncovered an important role of ABA, which bridges UV-B and plants\' adaptive response by remodeling the rearrangement of the cortical microtubules.
摘要：
UV-B辐射是限制植物生长的重要环境因素之一。先前已报道脱落酸（ABA）和微管都参与植物对UV-B的反应。然而,ABA和微管之间是否存在潜在的联系，以及植物对UV-B辐射响应的潜在信号转导机制仍不清楚。这里,通过使用sad2-2突变体植物（对ABA和干旱敏感）和外源施用ABA，我们看到ABA增强了拟南芥对UV-B胁迫的适应性反应（A.thaliana）。缺乏ABA的aba3突变体的异常肿胀根尖表明，ABA缺乏加剧了UV-B辐射施加的生长迟缓。此外,在有或没有UV-B辐射的aba3和sad2-2突变体中检查了根过渡区的皮质微管阵列。观察结果表明，UV-B重塑皮质微管，和高内源ABA可以稳定微管并减少其UV-B诱导的重组。为了进一步证实ABA在微管阵列中的作用，在外源ABA后评估根生长和皮质微管，紫杉醇,和以oryzalin喂养。结果表明，在UV-B胁迫条件下，ABA可以通过稳定横向皮质微管来促进根的伸长。因此，我们发现了ABA的重要作用，它通过重塑皮质微管的重排来桥接UV-B和植物的适应性反应。
