The Effects Of Overexpression Of Small Heat Shock Proteins On The Thermotolerence In Tomato

The small HSPs (sHSPs) is a kind of heat shock proteins of the family that ranged insizes from approximately 15 to 30 kDa. They play very important roles in plant'sthermotolerance. Under normal growth conditions, most sHSPs cannot be detected in theplant tissues, but they are rapidly produced in response to heat, with improvement of 200times. Some special sHSPs can express in certain stages of development of the plants, suchas embryogenesis, pollen development, seed maturation, seed germination and fruitmaturation.Many studies in vitro and in vivo indicate that sHSPs act as molecular chaperone incells. As molecular chaperones, sHSPs can bind to and facilitate the synthesizingpolypeptides to correct folding; leading new-synthesized polypeptides tranverse theorganelle membranes and locating them in different positions. Under high temperature stress,sHSPs can prevent the heat-denatured proteins assembling, prevent unreversible proteinsdenaturalization, or be propitious to the heat-denatured proteins renaturalization.In this experiment,an integrated vector pROKⅡof the LeHSP17.6 gene and NPTⅡgene(a kanamycin resistant gene) with CaMV35S promoter was constructed and introducedinto tomato mediated by Agrobacterium tumefaciens LBA4404. The result of Southernblotting indicated that the LeHSP17.6 gene has been integrated into the genomics of thetomato. The results of Northern and Western blotting indicated that the LeHSP17.6 gene hasbeen constitutively expressed in the tomato.A series of assays have been done such as heattreatment of the tomato plants under the temperature of 46℃for 6 hours,pollen dyeabilityand germination under high temperatures on the four transformants that have been finishedin our laboratory, and the responding molecular proves have been done. The main resultswere shown as follows:1) thermotolerance of the tomato plants:The control plants and the four transformants...