The Function Of Tomato Cell Wall Invertase Inhibitor (Le-INVINH1) In Plant Tolerance To Low Temperature Stress

The cell wall invertase inhibitor is a small molecular protein, which can control the activity of invertase in the post-translation level. Many studies shown that change the expression level of cell wall invertase inhibitor can rugulate the activity of cell wall invertase, and effect the development of fruits and seeds. In the earlier study of tomato cell wall invertase inhibitor, Researchers have confirmed that changing its expression affected the development of tomato fruits and seeds. However litter was known about its function of tomato tolerance to stress. In this study, tomato Zhongshu4is used to study the function of cell wall inhibitor in tomato resistance to low temperature stress.Since inhibitor over-expression in seed will lead to transgenic seeds abort, promoter rbcS3A is selected. Firstly Rubisco small subunit promoter rbcS3A was cloned by PCR, fused to the upstream of Gus coding region in a binary vector p1300RG, and transformed into tomato plants by Agrobacterium-mediated transformation. Histochemical staining on PCR positive plants was performed to analyze the expression pattern of the foreign gene regulated by the tomato rbcS3A promoter. Then fusing promoter fragment rbcS3A to the upstream of INVINH1coding region in a binary vector p1300RI, and introduced into tomato plants by Agrobacterium-mediated transformation. Three lines of cell wall invertase inhibit over expression plant were get and conformed by PCR and RT-PCR. Finally a series of experiment was done to study how transgenic tomato (Le-INVINH1RNAi interference plant we had before, Le-INVINH1over expression plant) and wild type tomato performed after low temperature treatment, The following results are obtained.Low temperature reduced INVINH1expression and increased cell wall invertase gene LIN6, LIN8expression. INVINH1affects the activity of invertase in the post-translation level and thus affects intracellular Glucose content. The change of intracellular Glucose level affects the expression level of CBF gene and ABA synthesis related gene which finally affect chilling tolerance of tomato.