LACK OF EVIDENCE FOR SEED TRANSMISSION OF CITRUS YELLOW VEIN CLEARING VIRUS DESPITE ITS FREQUENT DETECTION IN SEED TISSUES

Y. Zhou, H.M. Chen, X.F. Wang, Z.A. Li, M. Tang, C.Y. Zhou
doi: 10.4454/JPP.V97I3.023
Abstract:
Citrus yellow vein clearing virus (CYVCV), the putative causal agent of yellow vein clearing disease of citrus, is transmissible by grafting and is spread by aphids. However, whether CYVCV is seed-transmitted is not well documented. In this study, seed transmission of CYVCV was investigated in Daidai, Carrizo citrange and Rough lemon. CYVCV was detected in the endotesta, cotyledons and embryonic axis of seeds collected from the fruits of CYVCV-infected plants by qRT-PCR. Furthermore, the relative expression values of CYVCV were significantly higher in infected leaves than in the cotyledons or embryonic axis of seeds. Although viral RNA was found in few samples of radicles of germinating seed, none of the seedlings showed any symptoms for one year and were RT-PCR negative for CYVCV. The present study indicated that CYVCV could be localized in the seed tissues, but was not transmitted to the progeny. Absence of seed transmission may be consequent to the low CYVCV titre in embryo tissue.
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