Cucurbit aphid-borne yellows virus in Egypt
- 206 Downloads
During 2010, yellowing symptoms were frequently observed in cultivated squash fields in Egypt. A total of 717 symptomatic squash leaf samples were collected from four regions where squash cultivation is of economic importance for the country: Kafrelsheikh, El-Behira, El-Sharkia and El-Ismailia. Serological analysis showed that 95.6% of the symptomatic squash samples were infected by Cucurbit aphid-borne yellows virus (CABYV), and visual estimation of the incidence of yellowing symptoms suggested a very high incidence of CABYV in the fields. Twelve CABYV isolates were characterized by sequencing two regions of the viral genome, open reading frame (ORF) 3 and ORFs 4/5. Overall, Egyptian isolates were very similar among them, and had higher similarity values with a French than with a Chinese isolate. The average nucleotide diversity for ORF 3 was significantly higher than for the other two regions, indicating that variability is not evenly distributed along the viral genome. The ratios between nucleotide diversity values in non-synonymous (d N ) and synonymous (d S) positions (d N /d S) for each ORF showed that the three ORFs are evolving under different pressures, although predominantly under purifying selection. Phylogenetic analyses revealed that these Egyptian isolates, with only one exception, shared the same clade with a French isolate. Moreover, these analyses suggested that Egyptian isolates belong to the Mediterranean group described previously.
KeywordsCABYV Cucurbit diseases Luteoviridae Polerovirus
Part of this work was supported by grant 11934/PI/09 (Fundación Séneca de la Región de Murcia, Spain). We thank Miguel A. Aranda and Verónica Truniger for critically reading the manuscript, and Mari Carmen Montesinos and Blanca Gosalvez for their excellent technical assistance.
- FAO (2010). Statistical agriculture databases. httm://faostat.fao.org/
- Juarez, M., Kassem, M., Sempere, R., & Aranda, M. (2006). Cucurbit aphid-borne yellows virus in Spain. In G. P. Rao, P. Lavakumar, & R. J. Holguín-Peña (Eds.), Characterization, diagnosis and management of plant viruses, Vol. 3 (pp. 303-315). Vegetable and pulse crops. Houston, TX, USA: Studium Press.Google Scholar
- Lecoq, H. (1999). Epidemiology of cucurbit aphid-borne yellows virus. In H. G. Smith & H. Baker (Eds.), The Luteoviridae (pp. 243–248). Wallingford, UK: CABI Publishing.Google Scholar
- Lecoq, H. (2003). Cucurbits. In G. Loebenstein & G. Thottapilly (Eds.), Virus and virus-like diseases of major crops in developing countries (pp. 665–687). Dordrecht, the Netherlands: Kluwer Academic Publishers.Google Scholar
- Mayo, M. A., & D’Arcy, C. J. (1999). Family Luteoviridae: A reclassification of luteoviruses. In H. G. Smith & H. Barker (Eds.), The Luteoviridae (pp. 15–22). Wallingford, UK: CABI Publishing.Google Scholar
- Nei, M. (1987). Molecular evolutionary genetics. New York, NY: Columbia University Press.Google Scholar
- Rzhetsky, A., & Nei, M. (1992). A simple method for estimating and testing minimum evolution trees. Molecular Biology and Evolution, 9, 945–967.Google Scholar
- Xiang, H. Y., Shang, Q. X., Han, C. G., Li, D. W., & Yu, J. L. (2008). First report on the occurrence of Cucurbit aphid-borne yellows virus on nine cucurbitaceous species in China. Plant Pathology, 57, 390.Google Scholar
- Ziegler-Graff, V., Brault, V., Mutterer, J. D., Simonis, M.-T., Herrbach, E., Guilley, H., et al. (1996). The coat protein of beet western yellows luteovirus is essential for systemic infection but the viral gene products P29 and P19 are dispensable for systemic infection and aphid transmission. Molecular Plant-Microbe Interactions, 9, 501–510.CrossRefGoogle Scholar