Generation of transgenic watermelon resistance to Cucumber mosaic virus facilitated by an effective Agrobacterium-mediated transformation method

摘要

Watermelon is an annual vegetable crop that suffers from various diseases during growth. Genetic engineering is an effective tool for improving plant disease resistance. This paper presents an effective transformation protocol designed for a female parent watermelon line mediated by Agrobacterium. In this protocol, 2 times MS Fe-EDTA were supplemented into Murashige and Skoog (MS) medium to suppress the chlorosis during watermelon explants culturing, and the optimal preculture time (5 days) and coculture time (5 days) were screened out to improve the frequency of shoots regeneration. Using our protocol, 17 putative transgenic plants expressing artificial microRNAs that target Cucumber mosaic virus (CMV) 2a/2b genes were recovered, and seven of them were succeeded in obtaining T1 generation seeds because of the technique difficulties of self-pollination of the transgenic watermelon lines. PCR and Southern blot analyses confirmed that the transferred fragment was successfully imported and integrated into the genome of three of these seven transgenic lines. DAS-ELISA assay indicated that the CMV can be detected in the nontransgenic line but not in the transgenic lines, and the transgenic lines displayed resistance to CMV infection. (C) 2016 Elsevier B.V. All rights reserved.