Lü Bing, Gong Zhonghua, Wang Juan, Zhang Jianhua, Liang Jiansheng
College of Bioscience and Biotechnology, Key Laboratory of Crop Genetics and Physiology of Jiangsu Province, Yangzhou University, Yangzhou, PR China.
J Exp Bot. 2007;58(10):2565-72. doi: 10.1093/jxb/erm107. Epub 2007 Jun 1.
Microtubules play important roles in many physiological processes such as plant responses to drought stress. Abscisic acid (ABA) accumulates significantly in plants in response to drought conditions, which has been considered as a major response for plants to enhance drought tolerance. In this work, the focus was on the possible roles of microtubules in the induction of ABA biosynthesis in the roots of Zea mays when subjected to osmotic stress. The dynamic changes of microtubules in response to the stress were investigated by immunofluorescence staining, enzyme-linked immunosorbent assay, and a pharmacological approach. Disruption and stabilization of microtubules both significantly stimulated ABA accumulation in maize root cells, although this stimulation was markedly lower than that caused by osmotic stress. Cells in which the microtubule stability had been changed did not respond further to osmotic stress in terms of ABA biosynthesis. However, treatment with both a microtubule de-stabilizer and a stabilizer enhanced the sensitivity of cells to osmotic stress in terms of ABA accumulation. It is suggested that both osmotic stress and changes in microtubule dynamics would trigger maize root cells to biosynthesize ABA, and interactions between osmotic stress and microtubule dynamics would have an effect on ABA accumulation in root cells, although the exact mechanism is not clear at present.
微管在许多生理过程中发挥着重要作用，例如植物对干旱胁迫的响应。脱落酸（ABA）在干旱条件下会在植物中显著积累，这被认为是植物增强耐旱性的主要反应。在这项研究中，重点关注了微管在玉米根受到渗透胁迫时诱导ABA生物合成过程中可能发挥的作用。通过免疫荧光染色、酶联免疫吸附测定和药理学方法研究了微管对胁迫的动态响应变化。微管的破坏和稳定均显著刺激了玉米根细胞中ABA的积累，尽管这种刺激明显低于渗透胁迫所引起的刺激。微管稳定性发生变化的细胞在ABA生物合成方面对渗透胁迫不再有进一步反应。然而，用微管去稳定剂和稳定剂处理均增强了细胞在ABA积累方面对渗透胁迫的敏感性。研究表明，渗透胁迫和微管动态变化均会触发玉米根细胞生物合成ABA，并且渗透胁迫与微管动态变化之间的相互作用会影响根细胞中ABA的积累，尽管目前确切机制尚不清楚。
