First report of Tomato yellow leaf curl China virus infecting kidney bean in China

In 2004, a virus isolate (Bean-YM) was obtained from Kidney bean (Phaseolus vulgaris) showing leaf curl symptoms (Fig. 1) from Yuanmou, in the Yunnan province of China. To identify possible begomoviruses, total DNA was extracted from a leaf sample. Degenerate primers PA and PB, designed to amplify part of the intergenic region and coat protein (CP) gene of DNA-A of begomoviruses (Zhou et al., 2003), were used in PCR. A 500 bp DNA fragment was obtained, cloned and sequenced. Sequence comparison showed that the fragment was most closely related to Tomato yellow leaf curl China virus (TYLCCNV) isolate [Y43] (Acc. No. AJ781302) with 92% nucleotide sequence identity. Primers WTGs-1 (5'-CGTGCT GCTGTCCCCACTGT-3') and WTGs-2 (5'-GTGGAAATGACT ATATCGGC-3') were then designed to amplify the remaining DNA-A sequences of Bean-YM. The complete DNA-A sequence of Bean-YM was determined to be 2731 nucleotides (DQ256460). Comparisons with other begomoviruses showed that DNA-A of Bean-YM is closely related to TYLCCNYV-[Y43] with 92% nucleotide sequence identity.

All previously characterised TYLCCNV isolates have been shown to be associated with DNA ß molecules (Cui et al., 2004). To test whether a satellite molecule is associated with this isolate, a universal abutting primer pair specific for DNA β was used to amplify the putative DNA ß (Briddon et al., 2002). Using this primer set, an amplicon of approximately 1400 bp was obtained. Sequence analysis revealed that DNA ß of Bean-YM is 1336 nucleotides long (DQ256459) and most closely related to the DNA β associated with TYLCCNV-[Y10] (AJ421621; 80.8% nucleotide sequence identity).

TYLCCNV has previously been reported to infect tomato, tobacco and weeds. This is the first report of TYLCCNV infecting a legume.