Transmission of the Bean-Associated Cytorhabdovirus by the Whitefly Bemisia tabaci MEAM1

Abstract

The knowledge of genomic data of new plant viruses is increasing exponentially; however, some aspects of their biology, such as vectors and host range, remain mostly unknown. This information is crucial for the understanding of virus–plant interactions, control strategies, and mechanisms to prevent outbreaks. Typically, rhabdoviruses infect monocot and dicot plants and are vectored in nature by hemipteran sap-sucking insects, including aphids, leafhoppers, and planthoppers. However, several strains of a potentially whitefly-transmitted virus, papaya cytorhabdovirus, were recently described: (i) bean-associated cytorhabdovirus (BaCV) in Brazil, (ii) papaya virus E (PpVE) in Ecuador, and (iii) citrus-associated rhabdovirus (CiaRV) in China. Here, we examine the potential of the Bemisia tabaci Middle East-Asia Minor 1 (MEAM1) to transmit BaCV, its morphological and cytopathological characteristics, and assess the incidence of BaCV across bean producing areas in Brazil. Our results show that BaCV is efficiently transmitted, in experimental conditions, by B. tabaci MEAM1 to bean cultivars, and with lower efficiency to cowpea and soybean. Moreover, we detected BaCV RNA in viruliferous whiteflies but we were unable to visualize viral particles or viroplasm in the whitefly tissues. BaCV could not be singly isolated for pathogenicity tests, identification of the induced symptoms, and the transmission assay. BaCV was detected in five out of the seven states in Brazil included in our study, suggesting that it is widely distributed throughout bean producing areas in the country. This is the first report of a whitefly-transmitted rhabdovirus.

Illuminating the plant rhabdovirus landscape through metatranscriptomics data

“…The L protein-like TSA sequences included in the assembly of the BeTaV1 genome were previously reported to be 95–98% identical to soybean blotchy mosaic virus partial L gene sequences [18]; thus, it is tempting to speculate that the plant host of BeTaV1 may be soybeans. Recently, it was reported that the bean-associated cytorhabdovirus is efficiently transmitted by whiteflies, which was the first report of a whitefly-transmitted rhabdovirus [64], thus supporting our hypothesis that soybean blotchy mosaic virus may represent the second whitefly-transmitted rhabdovirus.…”

Diversity and Distribution of Viruses Infecting Wild and Domesticated Phaseolus spp. in the Mesoamerican Center of Domestication

“…Except for the 3′/N region, the P3/P4 region, which does not have the conserved consensus sequences, and the region L/5′ that had 12 of the 17 conserved nucleotides, all the intergenic regions have the highly conserved sequence 3′-TAAGAAAAACYGGGAKC-5′ ( Figure S5B ). BaCV-CN3 is closely related to the cytorhabdovirus BaCV strain BaCV-BR-GO ([ 26 ], GenBank accession MK202584], BaCV-LUZ ([ 27 ], GenBank accession MT811775), and Papaya cytorhabdovirus (PpVE) from Ecuador ([ 28 ], GenBank accession MH282832] ( Figure S5C ).…”

“…Based on the high nucleotide sequence identity between the cytorhabdovirus BaCV-BR-GO and PpVE, it was proposed that the virus species would be named Papaya cytorhabdovirus with strains PpVE infecting papayas and BaCV infecting beans [ 45 ]; thus, BaCV-CN3 is likely a strain of BaCV since it infects common bean and is closely related to the strains BaCV-BR-GO, BaCV-LUZ, as shown in the phylogenetic tree based on the RdRp amino acid sequences ( Figure S1C ). The vector of PpVE is unknown, and although BaCV is the first rhabdovirus reported to be transmitted to common beans by whitefly B. tabaci MEAM1 [ 27 ], the transmissibility of BaCV-CN3 by this vector was not determined. The symptoms induced by BaCV-CN3 could neither be confirmed because the sample from which it was identified was co-infected with BCMNV (GenBank accession MK069983).…”

“…Interestingly, BaCV and PpVE have also been identified in mixed infections. Pinheiro-Lima et al [ 27 ] found that 85 of the 91 common bean samples that tested positive to BaCV were co-infected with CPMMV, BGMV, or with CPMMV and BGMV, and although six samples were “single infected,” it is also possible that these samples were infected with another virus distinct to the ones tested; similarly, all the plants that tested positive to PpVE were also positive for Papaya ringspot virus (PRSV), and no differences in leaf symptoms were observed between PRSV single-infected plants and plants co-infected with both viruses [ 28 ]. Therefore, it is important to investigate if this group of viruses requires a helper virus, are seed-borne transmitted, and cause important economic losses.…”

Introduction to Special Issue of Plant Virus Emergence

“…Insects are significant drivers of virus emergence, as featured in submissions by Pinheiro-Lima et al, “ Transmission of the Bean-Associated Cytorhabdovirus by the Whitefly Bemisia tabaci MEAM1 ” [ 10 ], and Schoeny, et al, “ Can Winged Aphid Abundance Be a Predictor of Cucurbit Aphid-Borne Yellows Virus Epidemics in Melon Crop? ” [ 11 ].…”