First Report of the Occurrence of Sweet potato leaf curl virus in Tall Morningglory (Ipomoea purpurea) in China.

Abstract

Natural occurrence of Sweet potato leaf curl virus (SPLCV) has been reported in Ipomoea batatas (sweet potato, Convolvulaceae) or I. indica (Convolvulaceae) in several countries including the United States, Sicily, and China (1-3). In September of 2007, while collecting samples showing begomovirus-like symptoms in the Chinese province of Fujian, we observed tall morningglory (I. purpurea (L.) Roth, also known as Pharbitis purpurea (L.) Voigt), plants with slightly yellow mosaic and crinkled leaves. Total DNA was extracted from leaves of these plants and tested by rolling circle amplification (4). Amplification products were digested by the restriction enzyme BamHI for 30 min. Restriction products (2.8 kb) were then cloned into pMD18T vector (Takara Biotechnology, China) and sequenced. Comparison of complete DNA sequences by Clustal V analysis revealed that these samples were infected by the same virus, and an isolate denoted F-p1 was selected for further sequence analysis. F-p1 was 2,828 nucleotides, with the typical genomic organization of begomoviral DNA-A (GenBank Accession No. FJ515896). F-p1 was compared with the DNA sequences available in the NCBI database using BLAST. The whole DNA sequence showed the highest nucleotide sequence identity (92.1%) with an isolate of SPLCV (GenBank Accession No. FJ176701) from Jiangsu Province of China. The result confirmed that the samples from the symptomatic tall morningglory were infected by SPLCV. To our knowledge, this is the first report of the natural occurrence of SPLCV in I. purpurea, a common weed species in China.