Interaction Mechanism Between Tomato And TYLCV

Tomato yellow leaf curl virus disease(TYLCD)caused by tomato yellow leaf curl virus(TYLCV)has a serious impact on tomato production.At present,the research on TYLCD mainly focuses on the breeding of resistant varieties and the research on resistant genes,while the research on the interaction mechanism between tomato and yellow leaf curl disease is relatively less.In this study,‘Huamei 204’,‘Cooperative 909 big red tomato’ and ‘Money maker’ were selected to study the morphological characteristics and physiological and biochemical reactions after being infected,so as to provide a research basis for the study on the interaction mechanism between tomato and TYLCV.Then,tomato variety Money maker was used to study the interaction between different organs and TYLCV,to understand the interaction mechanism between TYLCV and different organs in tomato plants,and to find the signal pathway and related genes for TYLCV defense.Finally,on this basis,exogenous hormones or corticosteroids were sprayed to study the effects of exogenous hormones or corticosteroids on the interaction between tomato and TYLCV,so as to provide a theoretical basis for plant induced resistance to virus infection.The results are as follows:(1)The interaction between different tomato materials and TYLCV showed that 30 days after inoculation with TYLCV,plant height,leaf area,root weight and chlorophyll content of the susceptible tomato variety ‘Cooperative 909 big red tomato’ were significantly lower than those of the control plants.In addition to plant height,leaf area,root weight and chlorophyll content,the stem diameter of the susceptible tomato variety ‘Money maker’ was significantly lower than control plants.However,30 days after inoculation with TYLCV,the plant height,stem diameter,leaf area of the resistant tomato ‘Huamei 204’ still had no significant difference with control plants,and the chlorophyll content was higher than control plants.In the determination of photosynthetic parameters,it was found that net photosynthetic rate of the susceptible tomato ‘Cooperative 909 big red tomato’.The net photosynthetic rate,stomatal conductance,intercellular CO2 concentration and transpiration rate of tomato variety ‘Money maker’ were significantly decreased.There was no significant difference in the resistance variety ‘Huamei 204’.In terms of antioxidant enzyme activity,SOD activity in the leaves of the susceptible tomato ‘Cooperative 909 big red tomato’ was significantly lower than control plants,CAT had no significant difference,and POD activity increased significantly.The activities of SOD,POD and CAT in the leaves of ‘Money maker’ were significantly increased.Only the activities of POD were significantly increased in ‘Huamei 204’.It was found that O2-and H2O2,which are related to the activity of peroxidase,accumulated in the cells after inoculation with TYLCV,especially H2O2,accumulated in ‘Cooperative 909 big red tomato’ and ‘Money maker’.(2)Studies on the interaction between different organs of tomato plant and TYLCV showed that the activities of SOD and POD in roots,CAT in stems and SOD,POD and CAT in leaves were significantly increased 30 days after TYLCV inoculation by Money makers.As far as TYLCV content is concerned,it is the most in root,the second in stem and the least in leaf.In the study of SA,JA and et signaling pathways,it was found that SA signaling pathway and JA / ET pathway were co expressed in leaves,but antagonistic in roots.(3)Studies on the interaction between tomato and TYLCV induced by spraying exogenous hormones or parahormone showed that 0.5 m M SA pretreatment could significantly increase plant growth and chlorophyll content.Compared with the control sterile water pretreatment,the SOD activity decreased significantly after 0.1 u M COR pretreatment.The 0.5 m M JA pretreatment significantly decreased the activity of SOD and increased the activity of POD.The activities of SOD and CAT in leaves were significantly decreased and the activities of POD were significantly increased after 0.5m M SA pretreatment.COR,JA and SA pretreatment all reduced the accumulation of O2-and H2O2 in cells to different degrees.Through the determination of viral content and gene expression in different periods,it was found that SA、JA and COR could inhibit TYLCV replication to a certain extent,but with the extension of TYLCV inoculation time,there was no significant difference in virus content between SA pretreatment and control,while the virus content of JA and COR pretreatment was still lower than that of control,especially COR pretreatment could significantly reduce TYLCV content.No matter which hormone induced interaction between tomato and TYLCV,three signaling pathways are involved in the defense response of tomato plants against TYLCV.