First report of tomato yellow leaf curl virus infecting cowpea in China

Date:01-25-2011

Tomato yellow leaf curl virus (TYLCV) is a devastating pathogen of tomato that causes significant yield losses in many tropical and subtropical regions. In China, this virus was 1st found in 2006 on tomato in Shanghai.
 
In October 2008, chlorotic yellow leaves of cowpea (Vigna sinensis) were observed in Qingpu (district of Shanghai municipality) with 15-20 percent incidence in plants in high tunnels. Large populations of whiteflies were observed in association with the diseased cowpea.

The disease agent was transmitted to cowpea (and tomato) by whiteflies which resulted in chlorotic yellow leaves on cowpea (and yellow leaf curl symptoms on tomato) that were identical to those observed in the field. On the basis of the suspected insect vector, symptomatology and severe epidemics of tomato yellow leaf curl disease (TYLCD) in Shanghai in recent years, Tomato yellow leaf curl virus was suspected as the causal agent.
 
Polymerase chain reaction (PCR) was performed specific to TYLCV coat protein and an amplicon of the expected size was obtained in all 4 samples but not from healthy leaf samples. Sequences were identical among samples. Full-length viral DNA sequence was determined to be 2781 nucleotides. A comparison of the sequence with those in GenBank [database] shows that the cowpea isolate has the highest nucleotide sequence identity (99 percent) with a TYLCV isolate from tomato in Jiangsu province.
 
To our knowledge, this is the 1st report of TYLCV infecting cowpea in China and also the 1st report in the world.

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Source: Plant Disease [edited]
<http://apsjournals.apsnet.org/doi/abs/10.1094/PDIS-08-10-0608>