The Mechanism And Potential Factors Of The Interaction Between Microtubule Cytoskeleton And Abscisic Acid

Microtubules are one of the important components of the cytoskeleton and play crucial roles not only in cell movements but also in cell morphogenesis and cell growth regulation. In the meanwhile, Abscisic acid(ABA), a famous phytohormone, is involved in many different stresses response and almost all the key physiological processes including stoma movement, root and pollen tube elongation and so on. However, little is known that whether there is a link between microtubules and ABA besides the circumstance evidences.In this study, different mutant lines of Arabidopsis, named as MAP18 overexpressing mutant(OE), MAP18 RNAi transgenic mutant( R18) were used as materials to access the phenotype analysis of stomatal movement and root growth and microtubules dynamics with the help of confocal laser scanning microscope during the response to ABA compare with the wild type Arabidopsis. The results showed that ABA induced leaf pavement cell stomatal closure accompanied with microtubules depolymerization. The stomas of OE mutants fully closed with 75% ratio under 5 μmol/L ABA for 90 min, while the R18 mutants half closed with 80% ratio compare with half closed with 75% ratio and fully closed with 15% ratio of the wild type. We also analyzed the effects of ABA on the root elongation of mutant lines and found that radicle elongation of mutant OE slowed significantly from 0.60 cm/d to 0.12 cm/d in response to ABA, which is consistant with the data of stoma movement. The results suggested that MAP18 might involve in the process of ABA regulated stomatal movement and root growth through microtubule dynamics in Arabidopsis.