Molecular Characterization and Resistance Screening of Tomato Yellow Leaf Curl Thailand Virus in Taiwan

Conference Paper · January 2009with11 Reads

Conference: The 5th International Bemisia Workshop


    Tomato yellow leaf curl disease caused by begomoviruses (Family Geminiviridae,
    Genus Begomovirus) is a major tomato disease worldwide. As of 2003, three tomato
    begomoviruses, including the predominant Tomato Leaf Curl Taiwan Virus
    (TOLCTWV), have been reported in Taiwan. In 2007, TOLCTWV and a newly
    emerged begomovirus, the bipartite Tomato Yellow Leaf Curl Thailand Virus
    (TYLCTHV), were determined to be the predominant tomato begomoviruses in Taiwan
    by collecting 406 tomato samples from throughout the island and testing all by
    polymerase chain reaction using virus specific primers. The TYLCTHV isolates were
    highly homologous (>98.0% Nucleotide Identity) based on 1.5 Kb DNA-A sequences
    of 76 isolates. However, the TOLCTWV isolates had less homology with the 62
    isolates collected island-wide, showing from 78.5 to 99.9% identity to each other. The
    pathogenicity of TYLCTHV genomic DNAs was confirmed by co-agroinfection of
    infectious DNA-A and B, causing typical yellow leaf curl symptoms on tomato ‘ANT22’.
    It was confirmed that TYLCTHV was transmitted by the whitefly Bemisia tabaci
    (Biotype B), but it also could be transmitted by mechanical means. Viral DNA-A of
    TYLCTHV alone induced typical yellow leaf curl symptoms and was transmitted by
    whiteflies, but was not mechanically transmissible. So far, two out of 36 tomato lines
    have been determined to be TYLCTHV tolerant by screening in an insect-proof net
    house (50 Mesh) with viruliferous whiteflies. Results showed the newly emerged
    TYLCTHV should be considered a severe pathogen for tomato culture in Taiwan.