Diversity among isolates of cowpea severe mosaic virus infecting cowpeas in northeastern Brazil

Abstract

ABSTRACT. Eleven isolates of cowpea severe mosaic virus (CPSMV), a member of the genus Comovirus, were selected from 50 samples collected of nine cowpea fields in Northeastern Brazil (Piauí, Ceará, Rio Grande do Norte, Paraíba, Pernambuco, Alagoas, Sergipe, Bahia, and Distrito Federal) and partially sequenced. The RNA1 partial sequence, corresponding to the helicase, viral genome-linked protein, picornain 3C-like protease, and the RNA-directed RNA polymerase genes from CPSMV, had high identity among isolates, varying from 98 to 100%. No evidence was found for intermolecular or intramolecular recombination. Phylogenetic analysis confirmed that the Brazilian CPSMV isolates are substantially different from the CPSMV strain USA. Despite the low variability found among Brazilian CPSMV isolates, there were notable differences in the symptomatology of infected cowpea plants, ranging from mild to moderate. Previous reports have demonstrated an association between CPSMV symptom determinants and helicase. However, we found no correlation between the helicase ©FUNPEC-RP www.funpecrp.com.br Genetics and Molecular Research 11 (3): 3146-3153 (2012) Diversity among isolates of cowpea severe mosaic virus 3147 mutations and symptoms caused by CPSMV. Nevertheless, all isolates with mutation R to K in the protease provoked severe symptoms. This type of information can provide a foundation for the development of strategies to produce durable resistant cowpea lines. It is crucial for strategies based on DNA sequence-dependent technologies, such as inhibition with RNAi.

RNAi‐based enhanced resistance to Cowpea severe mosaic virus and Cowpea aphid‐borne mosaic virus in transgenic cowpea

“…In this study, a reproducible system was used to routinely achieve transgenic cowpea plants to express a chimerical gene comprising a fragment from the proteinase cofactor gene of CPSMV and a fragment of the coat protein gene of CABMV (ΔCSMVCABMV). These sequences are conserved among the Brazilian isolates of these viruses (Barros et al ., ; Abreu et al ., ; F. J. L. Aragão, unpublished results). It is hypothesized that engineering the RNAi concept in transgenic cowpea plants to silence these viral genes would reduce or prevent viral RNA accumulation, rendering resistant plants.…”

“…In this study, a reproducible system was used to routinely achieve transgenic cowpea plants to express a chimerical gene comprising a fragment from the proteinase cofactor gene of CPSMV and a fragment of the coat protein gene of CABMV (DCSMVCABMV). These sequences are conserved among the Brazilian isolates of these viruses (Barros et al, 2011;Abreu et al, 2012;F. J. L. Aragão, unpublished results).…”

“…The diseases caused by Cowpea severe mosaic virus (CPSMV; family Secoviridae, genus Comovirus) and Cowpea aphid-borne mosaic virus (CABMV; family Potyviridae, genus Potyvirus) are among the most prevalent diseases, leading to high yield losses in cowpea worldwide (Pio Ribeiro et al, 1978;Kareem & Taiwo, 2007;Abreu et al, 2012). CPSMV is transmitted by leaf-feeding beetles, mainly belonging to the family Chrysomelidae.…”

Feijão-fava: doenças virais e fúngicas

“…(1997), existem pelo menos nove sorotipos de CPS-MV e um número desconhecido de variantes patogênicas. Contudo, em estudos de caracterização de sequências parciais e completas de genomas de isolados brasileiros de CPSMV, observou-se baixa variabilidade genética (ABREU et al 2012;BESER-RA et al 2011;BOARI et al 2021;TEIXEIRA et al 2021).…”

A survey of RNA genome viruses in Lima bean crops of Northeastern Brazil

“…and common bean (Phaseolus vulgaris L.), have been reported. Those with the most predominance in the field are cucumber mosaic virus (CMV) (Eiras et al 2004), cowpea aphid-borne mosaic virus (CABMV) (Nicolini et al 2012), cowpea severe mosaic virus (CPSMV) (Abreu et al 2012) and cowpea mild mottle virus (CPMMV) (Lamas et al 2017). There are, however, few reports of viruses infecting lima bean (Carvalho et al 2015), possibly because lima bean is mainly cultivated by small farmers and has less economic importance than cowpea and common bean.…”