Microtubules Are Essential for Guard-Cell Function in Vicia and Arabidopsis  

作　　者：William Eisinger David Ehrhardt Winslow Briggs 

机构地区：[1]Department of Biology, Santa Clara University, Santa Clara, CA 95053, USA [2]Department of Plant Biology, Carnegie Institution for Science, Palo Alto, CA 94305, USA

出　　处：《Molecular Plant》2012年第3期601-610,共10页分子植物（英文版）

摘　　要：Radially arranged cortical microtubules are a prominent feature of guard cells. Guard cells expressing GFP- tubulin showed consistent changes in the appearance of microtubules when stomata opened or closed. Guard cells showed fewer microtubule structures as stomata closed, whether induced by transfer to darkness, ABA, hydrogen per- oxide, or sodium hydrogen carbonate. Guard cells kept in the dark （closed stomata） showed increases in microtubule struc- tures and stomatal aperture on light treatment. GFP-EB1, marking microtubule growing plus ends, showed no change in number of plus ends or velocity of assembly on stomatal closure. Since the number of growing plus ends and the rate of plus-end growth did not change when microtubule structure numbers declined, microtubule instability and/or rearrange- ment must be responsible for the apparent loss of microtubules. Guard cells with closed stomata showed more cytosolic GFP-fluorescence than those with open stomata as cortical microtubules became disassembled, although with a large net loss in total fluorescence. Microtubule-targeted drugs blocked guard-cell function in Vicia and Arabidopsis. Oryzalin dis- rupted guard-cell microtubules and prevented stomatal opening and taxol stabilized guard-cell microtubules and delayed stomatal closure. Gas exchange measurements indicated that the transgenes for fluorescent-labeled proteins did not dis- rupt normal stomatal function. These dynamic changes in guard-cell microtubules combined with our inhibitor studies provide evidence for an active role of microtubules in guard-cell function.Radially arranged cortical microtubules are a prominent feature of guard cells. Guard cells expressing GFP- tubulin showed consistent changes in the appearance of microtubules when stomata opened or closed. Guard cells showed fewer microtubule structures as stomata closed, whether induced by transfer to darkness, ABA, hydrogen per- oxide, or sodium hydrogen carbonate. Guard cells kept in the dark （closed stomata） showed increases in microtubule struc- tures and stomatal aperture on light treatment. GFP-EB1, marking microtubule growing plus ends, showed no change in number of plus ends or velocity of assembly on stomatal closure. Since the number of growing plus ends and the rate of plus-end growth did not change when microtubule structure numbers declined, microtubule instability and/or rearrange- ment must be responsible for the apparent loss of microtubules. Guard cells with closed stomata showed more cytosolic GFP-fluorescence than those with open stomata as cortical microtubules became disassembled, although with a large net loss in total fluorescence. Microtubule-targeted drugs blocked guard-cell function in Vicia and Arabidopsis. Oryzalin dis- rupted guard-cell microtubules and prevented stomatal opening and taxol stabilized guard-cell microtubules and delayed stomatal closure. Gas exchange measurements indicated that the transgenes for fluorescent-labeled proteins did not dis- rupt normal stomatal function. These dynamic changes in guard-cell microtubules combined with our inhibitor studies provide evidence for an active role of microtubules in guard-cell function.

关 键 词：cytoskeleton dynamics fluorescence imaging guard cells MICROTUBULES 

分 类 号：Q959.117[生物学—动物学] S572[农业科学—烟草工业]