Implication of the Whitefly Bemisia tabaci Cyclophilin B Protein in the Transmission of Tomato yellow leaf curl virus

Abstract

Tomato yellow leaf curl virus (TYLCV) is a single-stranded (ssDNA) begomoviruses that causes severe damage to tomato and several other crops worldwide. TYLCV is exclusively transmitted by the sweetpotato whitefly, Bemisia tabaci in a persistent circulative and propagative manner. Previous studies have shown that the transmission, retention, and circulation of TYLCV in its vector involves interaction with insect and endosymbiont proteins, which aid in the transmission of the virus, or have a protective role in response to the presence of the virus in the insect body. However, only a low number of such proteins have been identified. Here, the role of B. tabaci Cyclophilin B (CypB) in the transmission of TYLCV protein was investigated. Cyclophilins are a large family of cellular prolyl isomerases that have many molecular roles including facilitating protein-protein interactions in the cell. One cyclophilin protein has been implicated in aphid-luteovirus interactions. We demonstrate that the expression of CypB from B. tabaci is altered upon TYLCV acquisition and retention. Further experiments used immunocapture-PCR and co-immunolocalization and demonstrated a specific interaction and colocalization between CypB and TYLCV in the the midgut, eggs, and salivary glands. Membrane feeding of anti-CypB antibodies and TYLCV-infected plants showed a decrease in TYLCV transmission, suggesting a critical role that CypB plays in TYLCV transmission. Further experiments, which used membrane feeding with the CypB inhibitor Cyclosporin A showed decrease in CypB-TYLCV colocalization in the midgut and virus transmission. Altogether, our results indicate that CypB plays an important role in TYLCV transmission by B. tabaci.

Enhancing RNAi Efficiency to Decipher the Functional Response of Potential Genes in Bemisia tabaci AsiaII-1 (Gennadius) Through dsRNA Feeding Assays

“…However, contrary to cotton plants infected with silenced Hsp20, Hsp40, Hsp70, and k -1 whitefly which showed increased viral load, the plants infected with CYCP silenced whiteflies contained lower number of viral transcripts then the untreated plants ( Figure 7E). The obtained results are consistent with previous reports in which knockdown of cyclophilin (CYCP) in B. tabaci showed lower efficiency to transmit tomato leaf curl virus (Kanakala and Ghanim, 2016;Kanakala et al, 2019).…”

“…The target gene sequences were pulled out from whitefly genome database 1 . Selection of genes was done on the basis of their functional role i.e., osmoregulation (Aquaporin (AQP) (Benoit et al, 2014), Calcitonin (CAL) (Furuya et al, 2000;Cohen, 2012;Zandawala, 2012), virus transmission (Cyclophilin B (CYCP) (Kanakala and Ghanim, 2016), Knottin (k-1) (Hariton Shalev et al, 2016), Heat shock proteins i.e., Hsp20, Hsp40 and Hsp70 (Gotz et al, 2012;Gorovits and Czosnek, 2017) and other genes associated with vital processes i.e., SNF7 (SWItch/Sucrose Non-Fermentable) and IAP (inhibitor of apoptosis) (Blitvich et al, 2002). The expression of these genes was validated using gene specific primers (designed using Primer3 software) ( Table 1) in qRT-PCR performed using LightCycler R 96 System (Roche life sciences, Mannheim, German) with SYBR-Green detection (SYBR R Premix Ex TaqTMII, Takara).…”

The Incredible Journey of Begomoviruses in Their Whitefly Vector

“…CP immunolocalization has shown that TYLCVs concentrate in the digestive tract, especially the midgut and the filter chamber ( Figure 1 ,7,V) [ 56 , 57 , 58 ]. Other begomoviruses, such as the bipartite WmCSV, also concentrate in the midgut [ 57 ].…”

“…From the three B. tabaci peptidyl-prolyl isomerases protein genes (PPIases or cyclophilins Cyps) CypB , CypD and CypG , only the expression of CypB was upregulated by two-fold in viruliferous B. tabaci B. CypB and TYLCV CP formed complexes that could be resolved in vitro [ 58 ]. In addition, CypB and TYLCV CP co-localized in the filter chamber, cecae and midgut indicated that these interactions may mediate virus translocation in the haemolymph.…”

Deep Sequencing of Small RNAs in the Whitefly Bemisia tabaci Reveals Novel MicroRNAs Potentially Associated with Begomovirus Acquisition and Transmission

“…One of the most economically important begomoviruses transmitted by B. tabaci is tomato yellow leaf curl virus (TYLCV) [ 9 ], which has been the focus of numerous studies to better understand protein interactions between whiteflies and begomoviruses [ 10 , 11 , 12 ]. Transcriptome profiling has also been used to help understand the molecular mechanism of the whitefly–begomovirus relationship, including whitefly transcriptome responses to acquiring TYLCV [ 13 , 14 , 15 ] and tomato yellow leaf curl China virus (TYLCCNV) [ 16 ].…”