番茄及灰霉菌转化酶和糖转运蛋白基因在发病期的表达研究

Expression of Invertase and Sugar Transporter Genes in Both Tomato and Botrytis cinerea during the Development of Grey Mold

研究番茄叶片接种灰霉菌后番茄和病菌各自的转化酶和糖转运蛋白基因表达水平的变化规律,以阐明番茄和病菌各自的转化酶和糖转运蛋白在发病中的可能作用。通过系统测定接种后0、12、36和60 h番茄和灰霉菌的转化酶和糖转运蛋白基因的表达,结果发现,在接种后叶片逐渐发病,60 h时出现明显病斑。番茄叶片的CWIN基因LIN6表达水平在接种后12和60 h显著高于对照叶片,CWIN抑制蛋白基因INVINH1表达水平在接种后12 h也显著高于对照;番茄的2个STP基因SlSTP2和SlSTP1的表达水平分别在接种后12和60 h显著高于对照叶片;此外,番茄的3个CladeⅢSWEET基因SlSWEET10c、SlSWEET11a和SlSWEET11c在接种后12 h即显著高于对照叶片。灰霉菌胞外转化酶基因Bc1g10247的表达水平在接种叶片后大幅上升,此外BcHXT1、BcHXT6、BcHXT13这3个己糖转运蛋白的表达水平在接种后也呈大幅上升趋势。总之,番茄CWIN和STP基因表达水平的上升并不能有效诱导抗病反应并阻止灰霉菌吸收叶片中的糖分。相反,番茄Clade III SWEET表达的上升可能会导致蔗糖被大量转运至细胞外空间,而灰霉菌胞外转化酶和己糖转运蛋白表达量的上升则可将细胞外蔗糖分解为己糖并吸收利用,最终导致灰霉病的发生。

The dynamic changes in the expression levels of invertase and sugar transporter genes in both tomato and pathogens during the development of grey mold on tomato leaves caused by Botrytis cinerea were studied to clarify the possible roles of invertase and sugar transporter of tomato and pathogens in the pathogenesis.The expression of invertase and sugar transporter genes of tomato and Botrytis cinerea at 0,12,36,and 60 h after inoculation were systematically measured.It was found that the leaves were gradually infected and showed obvious disease lesions at 60 h after inoculation.The expression level of CWIN gene LIN6 in tomato leaves was significantly higher than that of control leaves at 12 and 60 h after inoculation,and the expression level of CWIN inhibitory protein gene INVINH1 was also significantly higher than that of control at 12 h after inoculation;the expression levels of two STP genes SlSTP2 and SlSTP1 in tomato were significantly higher than those of control leaves at 12 and 60 h after inoculation,respectively.In addition,the three Clade III SWEET genes SlSWEET10c,SlSWEET11a and SlSWEET11c of tomato were also significantly higher than those of control leaves at 12 h after inoculation.The expression level of the extracellular invertase gene Bc1g10247 of Botrytis cinerea rose sharply after inoculating to tomato leaves.Additionally,the expression levels of three hexose transporters including BcHXT1,BcHXT6 and BcHXT13 also showed a significant increase after inoculation.In short,the induced expression of tomato CWIN and STP genes cannot effectively enhance defense responses and prevent gray mold from absorbing sugar in tomato leaves.On the contrary,the increased expression of Clade III SWEET in tomato leaves may cause a large amount of sucrose to be exported to the extracellular space of tomato leaves,which is subsequently hydrolyzed into hexose(glucose and fructose)and absorbed into the fungal cells by the induced extracellular invertase and hexose transporter in Botrytis cinerea,eventually leading to the incidence of grey mold.