Transovarial Transmission of Dolichos Yellow Mosaic Virus by Its Vector, Bemisia tabaci Asia II 1

Abstract

The cultivation of dolichos bean [Lablab purpureus (L.) Sweet] has been severely affected by dolichos yellow mosaic virus (DoYMV, Begomovirus) transmitted by whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae). We tested the transovarial transmission of DoYMV in next-generation B. tabaci by PCR, real-time PCR, Southern blot hybridization, and biological transmission. The eggs, laid by DoYMV-exposed B. tabaci, carry the virus in a unique pattern. Only the eggs laid in between 3 and 6 days post virus acquisition by a parent B. tabaci were DoYMV positive. When tested individually in real-time PCR, around 31–53% of the eggs carried the virus. The presence of DoYMV in ovaries and F1 eggs was further substantiated by the hybridization of a Cy3-conjugated nucleic acid probe complementary to the viral strand of DoYMV. Viral DNA was also detected in F1 adults and F2 eggs. B. tabaci progenies carried not only the DoYMV DNA but were also infective. The F1 adults transmitted DoYMV to all tested plants and produced strong yellow mosaic symptoms. An increase in viral copies from egg to nymphal stage indicated propagation of DoYMV in B. tabaci. However, the increase was for a short period and decreased thereafter. The present study provides the first evidence of transovarial transmission and propagation of a bipartite begomovirus in its vector, B. tabaci Asia II 1. The transovarial transmission and replication of DoYMV in B. tabaci have great epidemiological relevance as B. tabaci can serve as a major host of the virus to bridge the gap between the cropping seasons.

Emerging evidence of seed transmission of begomoviruses: implications in global circulation and disease outbreak

“…This is how the whitefly transmission of begomovirus is referred as a circulative persistent mode of transmission. However, while persisting in the whitefly body, viral replication and transovarial transmissions of begomovirus is not clear yet, as the current studies have shown inconsistent results (Ghanim et al, 1998;Bosco et al, 2004;Becker et al, 2015;Sanchez-Campos et al, 2016;Fiallo-Olive and Navas-Castillo, 2019;Guo et al, 2018;Ghosh et al, 2021).…”

Transcriptomic Changes of Bemisia tabaci Asia II 1 Induced by Chilli Leaf Curl Virus Trigger Infection and Circulation in Its Vector

“…RFA1 is an ssDNA binding protein ( Wold, 1997 ). Although replication factors play an important role in DNA replication, recombination, and repair ( Vanoli et al, 2010 ; Yamamoto et al, 2019 ), ChiLCV-DNA does not replicate within the vector ( Rosen et al, 2015 ; Ghosh et al, 2021 ). This rejected the possibility of involvement of RFA1 in virus multiplication in B. tabaci .…”

How many begomovirus copies are acquired and inoculated by its vector, whitefly (Bemisia tabaci) during feeding?

“…TYLCV, tomato yellow leaf curl China virus (TYLCCNV), tomato leaf curl Bangalore virus (ToLCBaV), papaya leaf curl China virus (PaLCuCNV), tomato leaf curl Taiwan virus (ToLCTWV), tomato yellow leaf curl Thailand virus (TYLCTHV), euphorbia yellow mosaic virus (EuMV), and tobacco curly shoot virus (TbCSV) are transmitted by different B . tabaci cryptic species at varying efficiencies [ 34 , 40 – 42 , 47 – 55 ]. A steady increase in the ToLCNDV copies was observed 6 hrs post feeding.…”