Although recent studies have suggested that the microfilament (MF) cytoskeleton of plant cells participates in the response to salt stress, it remains unclear as to whether the MF cytoskeleton actually plays an active role in a plant's ability to withstand salt stress. In the present study, we report for the first time the role of MFs in salt tolerance of Arabidopsis thaliana. Our experiments revealed that Arabidopsis seedlings treated with 150 mm NaCl maintained MF assembly and bundle formation, whereas treatment with 250 mm NaCl initially induced MF assembly but subsequently caused MF disassembly. A corresponding change in the fluorescence intensity of MFs was also observed; that is, a sustained rise in fluorescence intensity in seedlings exposed to 150 mm NaCl and an initial rise and subsequent fall in seedlings exposed to 250 mm NaCl. These results suggest that MF assembly and bundles are induced early after salt stress treatment, while MF polymerization disappears after high salt stress. Facilitation of MF assembly with phalloidin rescued wild-type seedlings from death, whereas blocking MFs assembly with latrunculin A and cytochalasin D resulted in few survivors under salt stress. Pre-treatment of seedlings with phalloidin also clearly increased plant ability to withstand salt stress. MF assembly increased survival of Arabidopsis salt-sensitive sos2 mutants under salt stress and rescued defective sos2 mutants. Polymerization of MFs and its role in promoting survival was also found in plants exposed to osmotic stress. These findings suggest that the MF cytoskeleton participates and plays a vital role in responses to salt and osmotic stress in Arabidopsis.

Cold is a typical environmental stress factor that limits the geographical distribution and growth of various plants. It affects crop quality and productivity. In the contemporary years, with the plant cold‐resistant genetic engineering development, great progress was obtained in this field. This paper gave a general statement about the development of plant cold resistantance on the level of unsaturated fatty acids, protective enzymes, functional genes and regulation genes, aiming to provide some useful information and ideas to researchers who work on plant cold breeding and the mechanism of cold resistance. As research continues, we could develop further multiple resistant plant species.