Malvastrum yellow vein virus, a new Begomovirus species associated with satellite DNA molecule

Virus isolate Y47 was obtained from Malvastrum coromandelianum showing yellow vein symptom in Honghe, Yunnan Province. The complete nucleotide sequence of DNA-A was determined, it contains 2731 nucleotides, having typical genomic organization of a begomovirus, encoding 6 ORFs with 2 ORFs [AV1(CP) and AV2] in virion- sense DNA and 4 ORFs (AC1—AC4) in complementary- sense DNA. Comparisons show that the total DNA-A of Y47 has the highest sequence identity (77%) with that of Okra yellow vein mosaic virus-[201] (AJ002451), while less than 76% identities are found when compared with other begomoviruses. The molecular data show that virus isolate Y47 is a distinct begomovirus species, for which the name Malvastrum yellow vein virus is proposed. Satellite DNA molecule (Y47b) was found to be associated with Y47 using the primers (beta01 and beta02) specific for DNAb. Y47b consists of 1348 nucleotides, with a functional ORF (C1) in complementary-sense DNA. Y47b has 62%—67% sequence identity with DNAb molecule associated with Cotton leaf curl Multan virus or Cotton leaf curl Rajasthan virus, while lower than 46% sequence identities are found when compared with other reported DNAb molecules. Relationship dendrograms show that DNAb molecules are co-evolved with their help begomoviruses.