Mechanism Of Validamycin Inhibiting Transmission Of Tomato Chlorosis Virus By Bemisia Tabaci

Bemisia tabaci is a crop pest with a host range of over 1000 plant species,and it is the main vector of Tomato chlorosis virus(ToCV).Therefore,an efective control strategy for ToCV must include measures that reduce the density and activity of the B.tabaci vector in the feld.Many insects rely on the hydrolysis of trehalose,broken down by the enzyme trehalase,to power their flight and other life-sustaining activities.B.tabaci encodes just one trehalase,making it an attractive target.Validamycin is one of the known trehalase inhibitors.However,the inhibitory effect of Jinggangmycin on Bemisia tabaci and its transmitted viral diseases is still lacking.Therefore,our study took Validamycin as the object to study its effects on glucose metabolic,flight and feeding behavior during the transmission of ToCV by B.tabaci.These provides an important theoretical basis for targeting whitefly trehalase as one way to control ToCV transmission.The main results are as follows:1.Upon treatment with 200 mg/L validamycin,compared to the control group,the trehalose content of B.tabaci that fed on ToCV-infected tomato plants increased with the extension of feeding time.By contrast,trehalase activity in B.tabaci that fed on ToCV-infected tomato plants decreased significantly.With the extension of feeding time,the trehalase in whitefies had lower activity compared to the control group.These results indicated that Validamycin treatment inhibited trehalose metabolism in viruliferous whiteflies.2.Validamycin significantly reduced the transmission rate,transmission efficiency and emergence rate of ToCV by B.tabaci.After validamycin treatment,the number of viruliferous whitefies that preferred healthy tomato plants was significantly reduced.3.Validamycin could effectively inhi bit the flight and feeding behavior of viruliferous whiteflies.Compared to the control group,flight distance,time and velocity of viruliferous whiteflies all significant decreased.After Validamycin treatment,the duration of waveform np(non-probing behavior)was longer,while the duration of waveform C(intercellular stylet pathway)and E(phloem ingestion)were shorter in viruliferous whiteflies.Our findings suggested that Validamycin significantly disrupted the feeding of the phloem of whiteflies.4.Foliar spraying of Validamycin on tomato plants increased antioxidant enzyme activity,enhanced trehalose and soluble sugar content,decreased MDA content,so as to reduce the damage of reactive oxygen species to cell membrane and alleviate the peroxidation of phospholipids in cell membrane.The results showed that Validamycin could affect the physiological characteristics of tomato.