Atmap65-1 May Be Involved In Regulating Guard Cell Microtubules Arranged In The Way Experimental Basis

Stomatal guard cells become a typical and highly developed model system for dissecting signal transduction mechanisms in plants, because they have the ability to sense and response to various environmental stresses such as drought and cold quickly and effectively. Today, with the environment getting more and more tough, revealing the signaling pathway during stomatal movement is a goal of many biologists. Many factors such as light, CO₂, ABA, H₂O₂, NO, protein kinase, cytoskeleton et al, have been discovered to engage in stomatal signaling. Experimental study base on Arabidopsis, AtMAP65-1 gene was cloned from Arabidopsis genome. A plant expression vector containing AtMAP65-1-GFP fusion gene driven by 35S promoter was constructed and introduced into Arabidopsis by Agrobacterium infection. Under confocal laser scanning microscope (CLSM), it was found that :①in the light-induced opening guard cells AtMAP65-1 was distributed radiately from dorsal wall to ventral wall in a bundling way; ②Treated with microtubule specific inhibitor-Vinblastine (10μmol/L) for 90 min, the organization of AtMAP65-1 in guard cell was disrupted dramatically. Following the depolymerization of cortical microtubule and the decreasing of stomatal aperture, the fluorescence of AtMAP65-1 became to be fragmented into dotted spots. The organization of AtMAP65-1 was broken up completely with the treatment to 120 min; ③ In the dark-induced closing guard cells, AtMAP65-1 was turned into fragments and was randomly dispersed throughout the cells. That is, AtMAP65-1 is co-localized with cortical microtubules. The results suggest that AtMAP65-1 binds cortical microtubules and may regulate the arrangement of cortical microtubules, which helps us gain more insights into the role of AtMAP65-1 in stomatal movement.