Characterization of a new monopartite begomovirus with a Betasatellite Associated with Leaf Curl, Yellow Vein, and Vein Enation in Hibiscus rosa-sinensis

Abstract

A new begomovirus, tentatively named hibiscus yellow vein leaf curl virus (HYVLCV), was identified in Hibiscus rosa-sinensis plants showing symptoms of leaf curl, yellow vein, and vein enation on the undersides of the leaf in Taiwan. Sequence analysis of the full-length HYVLCV genome from the rolling cycle amplicon revealed a genome of 2,740 nucleotides that contains six open reading frames and a conserved sequence (5¢-TAATATTAC-3¢) commonly found in geminiviral genomes. HYVLCV shares the highest nucleotide identity (88.8%) with cotton leaf curl Multan virus (CLCuMuV) genome, which is lower than the criteria (91%) set for species demarcation in the genus Begomovirus. No begomoviral DNA-B was detected; however, a begomovirus-associated DNA betasatellite (DNA-b) was detected. The DNA-b (1,355 nucleotides) shares the highest nucleotide identity (78.6%) with malvastrum yellow vein betasatellite (MaYVB). Because the identity is slightly higher than the criteria (78%) set for the species demarcation threshold for a distinct DNA-b species, the DNA-b of HYVLCV reported in this study is considered the same species of MaYVB and tentatively named MaYVB-Hib. An expected 1,498-bp fragment was amplified with two HYVLCV-specific primers from 10 of 11 field-collected samples. Four independent amplicons were sequenced, revealing 100% nucleotide identity with the HYVLCV genome. Agroinoculation of a dimer of the infectious monopartite genome alone to Nicotiana benthamiana resulted in mild symptoms at 28 days postinoculation (dpi); coagroinoculation with the DNA-b satellite resulted in severe symptoms at 12 dpi. HYVLCV could be transmitted to healthy H. rosa-sinensis by grafting, resulting in yellow vein symptoms at 30 dpi.