Rearrangements of microtubule cytoskeleton in stomatal closure of Arabidopsis induced by nitric oxide  

作　　者：ZHANG YongMei WU ZhongYi WANG XueChen YU Rong 

机构地区：[1]College of Life Sciences, Capital Normal University, Beijing 100037, China [2]Beijing Agro-Biotechnology Research Center, Beijing Academy of Agriculture and Forestry Sciences, Beijing 100097, China [3]State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100094, China

出　　处：《Chinese Science Bulletin》2008年第6期848-852,共5页

基　　金：the New Star Plan of Science & Technology of Beijin, China (Grant No. 2003B34);National Natural Science Foundation of China (Grant Nos. 30600318 and 30400228)

摘　　要：NO (nitric oxide), known as a key signal molecule in plant, plays important roles in regulation of stomatal movement. In this study, microtubule dynamics and its possible mechanism in the NO signal pathway were investigated. The results were as follows: (i) In vivo stomatal aperture assays revealed that both vinblastine (microtubule-disrupting drug) and SNP (exogenous NO donor) prevented stomatal opening in the light, and vinblastine even could enhance the inhibitory effect of SNP, whereas taxol (a microtubule-stabilizing agent) was able to reduce this effect; (ii) microtubules in the opening Arabi- dopsis guard cells expressing GFP:α-tubulin-6 (AtGFP:α-tubulin-6) were organized in parallel, straight and dense bundles, radiating from the ventral side to the dorsal side, and most of them were localized perpendicularly to the ventral wall; (iii) under the same environmental conditions, treated with SNP for 30 min, the radial arrays of microtubules in guard cells began to break down, twisted partially and be- came oblique or exhibited a random pattern; (iv) furthermore, the involvement of cytosolic Ca2+ in this event was tested. Stomatal aperture assays revealed that BAPTA-AM (a chelator of Ca2+) greatly sup- pressed the effect of NO on stomatal closure; however, it did not show the same function on stomatal closure induced by vinblastine. When BAPTA-AM was added to the SNP-pretreated solution, the SNP-induced disordered microtubulue cytoskeleton in guard cells underwent rearrangement in a time-dependent manner. After 30 min of treatment with BAPTA-AM, the cortical microtubules resumed the original radial distribution, almost the same as the control. All this indicates that NO may promote rearrangement of microtubule cytoskeleton via elevation of [Ca2+]cyt (free Ca2+ concentration in the cy- toplasm), finally leading to stomatal closure.NO （nitric oxide）, known as a key signal molecule in plant, plays important roles in regulation of stomatal movement. In this study, microtubule dynamics and its possible mechanism in the NO signal pathway were investigated. The results were as follows： （i） In vivo stomatsl aperture assays revealed that both vinblastine （microtubule-disrupUng drug） and SNP （exogenous NO donor） prevented stomatsl opening in the light, and vinblastine even could enhance the inhibitory effect of SNP, whereas tsxol （a microtubule-stsbilizing agent） was able to reduce this effect; （ii） microtubules in the opening Arabi-dopsis guard cells expressing GFP：a-tubulin-6 （AtGFP：a-tubulin-6） were organized in parallel, straight and dense bundles, radiating from the ventral side to the dorsal side, and most of them were localized perpendicularly to the ventral wall; （iii） under the same environmental conditions, treated with SNP for 30 min, the radial arrays of microtubules in guard cells began to break down, twisted partially and be- came oblique or exhibited a random pattern; （iv） furthermore, the involvement of cytosolic Ca^2＋ in this event was tested. Stomatal aperture assays revealed that BAPTA-AM （a chelator of Ca^2＋） greatly suppressed the effect of NO on stomatal closure; however, it did not show the same function on stomatal closure induced by vinblastine. When BAPTA-AM was added to the SNP-pretreated solution, the SNP-induced disordered microtubulue cytoskeleton in guard cells underwent rearrangement in a time-dependent manner. After 30 min of treatment with BAPTA-AM, the cortical microtubules resumed the original radial distribution, almost the same as the control. All this indicates that NO may promote rearrangement of microtubule cytoskeleton via elevation of [Ca^2＋]cyt （free Ca^2＋ concentration in the cytoplasm）, finally leading to stomatsl closure.

关 键 词：氧化一氮 微管细胞骨架 气孔运动 气孔关闭 钙离子 

分 类 号：Q945.1[生物学—植物学]