| Mulberry is an important economic tree in China,and because of its strong stress resistance,it has become an important material for plant ecological science research.The selection and study of mulberry stress resistance genes can provide genetic resources for mulberry resistance breeding.Among the identified plant resistance genes,osmotins(OSMs)have important regulatory effects when plants are under stress,but functional studies of mulberryOSM have not been reported.Phospholipases,as a class of enzymes in the body responsible for biosynthesis and phospholipid metabolism,are also closely related to plant stress resistance.The Ma PLA1-?? gene is an important class in the phospholipase family,and its discovery and research started late.The research on mulberry Ma PLA1-?? has not been reported.Therefore,the further study of mulberry osmotonin and plant phospholipase is of great significance to promote the molecular mechanism of stress resistance of mulberry.In this study,Morus Seedlings grown for 45 days were used as materials.Four members of the mulberry Ma PLA1-?? and the mulberry osmotonin gene MaOSM were cloned.The gene expression pattern analysis and drought response stress analysis were performed.The above genes were transformed into Arabidopsis thaliana,and over-expressed Arabidopsis plants were obtained,and wild-type Arabidopsis thaliana was used as a control.Drought resistance analysis was performed from multiple levels such as phenotype,physiology,biochemistry,and gene expression.The following results:(1)Each member of the MaOSM and Ma PLA1-?? gene families is expressed in mulberry leaves,buds,roots,and flowers,and all have high expression levels in the roots.ABA,salt,cold and drought stress can induce the expression of each member of MaOSM and Ma PLA1-??,and are strongly induced by drought.(2)The expression level of MaOSM plays an important role in the development of root hairs.Physiological and biochemical analysis shows that the expression of MaOSM is closely related to the drought resistance of overexpressing plants.The higher the expression of MaOSM,the stronger the drought resistance.(3)Analysis of the morphological aspects of the transgenic Ma PLA1-?? A.thaliana showed that the transgenic Ma PLA1-?? plants showed early bolting.Under normal growth conditions,there is no significant difference in growth between the transgenic Ma PLA1-?? plants and wild-type plants,but under drought conditions,overexpression of Ma PLA1-?? will increase the germination rate of plant seeds,promote seedling rooting,and promote the extension of plant stems.Has a positive regulatory effect.(4)Examination of physiological indicators found that Ma PLA1-?? over-expressing plants contained more osmolytes,proline,to resist drought damage to cells,and that up-regulation of Ma PLA1-?? gene could reduce the degree of damage to plant cell membranes and increase Cell protoplast stability effectively enhances plant drought resistance.(5)Over-expressing Ma PLA1-?? plants will cause stomata to close and reduce water loss under drought conditions.Analysis of the content of antioxidant substances in plants found that an increase in the activity of antioxidant enzymes will enhance the clearance of ROS and enhance the protective mechanism in vivo.In addition,the closing of stomata will lead to a decrease in photosynthesis and a decrease in ROS biosynthesis,thereby reducing the degree of damage to plant cells.Achieve drought resistance.Studies have shown that both mulberry MaOSM and Ma PLA1-? ? are drought-responsive genes,and over-expression can increase the drought resistance of plants.Mulberry osmotonin may reduce the damage of cell membrane by drought stress by up-regulating the content of osmoregulation substances,thereby improving the tolerance of plants to drought stress.The mulberry Ma PLA1-?? protein works by enhancing the activity of antioxidant enzymes and regulating the opening and closing of stomata,thereby improving the drought resistance of transgenic plants. |
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