October 8, 2003
From: British Society for Plant Pathology, New Disease Reports [edited]

First report of Sida golden yellow vein virus infecting Sida species in Cuba

A.L. Echemendia (Instituto de Investigaciones de Sanidad Vegetal, 110 # 514, Playa. La Habana. CP 11600. Cuba); P.L. Ramos < pedro.ramos@cigb.edu.cu >; L. Díaz (as for Ramos); R. Peral (as for Ramos); A. Fuentes (as for Ramos); M. Pujol (as for Ramos); and G. Gonzalez (as for Echemendia). Accepted for publication 29 Sep 2003.

Members of the genus _Sida_ are common weeds in the Caribbean and Central America. _Sida_ spp. with leaves showing yellow mottling have been commonly observed in Cuba. To identify the causal agent(s), symptomatic leaves from _Sida_ plants were collected in the provinces of Havana, Santa Clara, and Guantanamo between 1999 and 2001.

Healthy _Phaseolus vulgaris_ L. plants were inoculated using a bioballistic method (Finer et al., 1992) with total DNA extracts purified from infected leaves collected in Havana. Yellow mosaic and curling leaf symptoms were observed in 3 of 15 inoculated bean plants.

The presence of a begomovirus in both _Phaseolus_ and _Sida_ samples was shown by strong hybridization signals in Southern blots using DNA-A from Bean golden yellow mosaic virus-Cu as a probe, under high stringency conditions.

Total DNA from the Havana Sida sample was further analyzed by PCR using 2 degenerate primer sets; PAL1v1978-PAR1c715 and PAL1c1960-PAR1v722 (Rojas et al., 1993). Amplicons of approximately 1.4 kb and 1.2 kb were amplified and cloned into pZeroTM-2.1 plasmid (Invitrogen, CA, USA) using standard procedures.

Nucleotide sequences were compared to those from known begomoviruses using Clustal W analysis. For the coat protein (753 nucleotides [nt]) and rep genes (1080 nt), the highest percentages of identity (93.5 and 99 percent respectively) were to Sida golden yellow vein virus (SiGYVV, GenBank Accession No. U77964).

In addition, the Cuban isolate (DNA-A 2600 nt) showed 97percent nt sequence identity with SiGYVV-A. Common region (CR) analysis of SiGYVV-Cu A revealed 98 percent identity when compared to SiGYVV-CR. Similar interons were identified in both viruses. These results confirm that the virus isolated from _Sida_ plants in the province of Havana (GenBank Accession No. AJ 577395) is a strain of SiGYVV.

This is the first identification of SiGYVV in Cuba.

References
Rojas MR, Gilbertson RL, Russell DR, Maxwell DP, 1993. Use of degenerate primer in the polymerase chain reaction to detect whitefly-transmitted geminiviruses. Plant Disease 77, 340-347.
Finer JJ, Vain P, Jones MW, McMullen MD, 1992. Development of the particle inflow gun for DNA delivery to plant cells. Plant Cell Reports 11, 323-328.

[To my knowledge, SiGYVV has not been previously reported to infect bean. If any of our readers in the Caribbean and Central America know of reports documenting infection of bean or other food crop legumes by SiGYVV, I would appreciate receiving them. Weeds such as _S. rhombifolia_ have been suggested as natural reservoirs from which the whitefly, _Bemisia argentifolii_, spreads SiGYVV to tomato, a preferred host. In addition to SiGYVV, there are at least 4 other geminiviruses that infect _Sida_ spp. (golden mosaic, mottle, yellow vein, and yellow mosaic). - Mod.DH]