影響粉蝨傳播番茄黃捲葉泰國病毒的病毒獲取與接種因子

Abstract

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Bemisia tabaci, one of the most important whiteflies in terms of virus transmission, is commonly found in tropical and sub-tropical regions. The direct harm caused by. B. tabaci is linked to their feeding on the phloem sap of plants, resulting in a decrease in plant vigor. It also transmits over 300 species of plant viruses, including members of the genus Begomovirus. Begomoviruses pose significant risks to the cultivation of numerous vegetable, root, and fiber crops across tropical, subtropical, and temperate regions worldwide, emerging as serious threats to their production. Begomoviruses are transmitted exclusively by whiteflies. The mode of vector transmission of begomoviruses is generally believed to be persistent-circulative. For successful inoculation to healthy plants upon virus acquisition, begomoviruses must overcome the midgut and primary salivary gland barriers in B. tabaci. The objectives of this study were to examine: 1) the effect of acquisition time on virus infection in whitefly; 2) the effect of inoculation time on virus ejection by whitefly; and 3) the effect of the titer of source plant on virus infection in whitefly, ejection, and transmission by whitefly. The effect of acquisition time on the tomato yellow leaf curl Thailand virus (TYLCTHV) infection in the midgut and primary salivary glands (PSGs) of B. tabaci was evaluated by qPCR. The results showed the virus titer in the midgut increased from 1-h acquisition access period (AAP) to 24-h AAP, and the virus titer in the PSGs increased from 1-h AAP to 48-h AAP. The effect of inoculation time on the ejection of TYLCTHV with whitefly saliva was evaluated by the virus titer in the Chinese kale leaf disc that was fed by viruliferous whiteflies. The virus titer in the leaf disc was determined by qPCR. The virus titer in the leaf disc increased from 1-h AAP to 24-h AAP and then decreased to 48-h AAP. The effect of source plant titer on the TYLCTHV infection in the midgut and PSGs of B. tabaci was also evaluated by qPCR. The results showed the virus titers in the midguts of whiteflies that fed on source plants with the relative titers 14-16 and 9-11 were higher than that of whiteflies that fed on source plants with the relative titers 4-6. For PSG, the virus titers in the PSGs of whiteflies that fed on source plants with the relative titers 4-6 and 9-11 were higher than that of whiteflies that fed on source plants with the relative titers 14-16. The effect of source plant titer on the ejection of TYLCTHV with whitefly saliva was evaluated by the virus titer in the Chinese kale leaf disc that was fed by viruliferous whiteflies. The virus titer in the leaf disc was determined by qPCR. The results showed the virus titer in the leaf disc of the treatment source plant titers 14-16 was higher than that of the treatment source plant titers 4-6 and 9-11. The effect of source plant titer on the transmission rate of TYLCTHV by whitefly was evaluated by PCR. The results showed the transmission rates of three treatments were not significantly different among treatments.