My program emphasizes research and extension on the biology and control of virus diseases of vegetable and fruit crops. A primary research goal is to understand how viruses cause diseases by studying the molecular and genetic basis of virus-host interaction and virus-vector relationship. Increasing our knowledge of the mechanisms of virus infection will facilitate the design of more effective and environmentally friendly control strategies. The ultimate goal of my research program is to develop control measures for virus diseases of vegetable and fruit crops through improved diagnostic methods, cultural practices, traditional breeding, and genetic engineering. A related objective is to address environmental safety issues over virus-resistant transgenic plants in order to lessen potential risks while preserving the efficacy of this control strategy. The goals of the extension component of my program include the identification of emerging virus diseases, the education of extension personnel and growers, and the implementation of management procedures of virus diseases of vegetable and fruit crops. I am also leading a certification program for grapes and a statewide survey of stone fruits for plum pox virus in terms of an eradication program.

Plant viruses can cause severe crop losses. For example, grapevine fanleaf virus (GFLV) is a nematode-borne virus that poses a serious threat to the grapevine industry, especially in California, Chile and France. It reduces crop yield and lowers fruit quality. Traditional control measures against GFLV in infected vinyeards are essentially directed to the eradication of nematode vectors through cultural practices and soil disinfection. These measures are of limited efficacy and environmentally hazardous. Therefore, there is a need to develop GFLV-resistant grapevines. My research program aims at developing GFLV-resistant rootstocks through biotechnologucal approaches. This research will directly benefit grape growers, and wine producers and consumers.

Engineered resistance is applied to grapevine fanleaf virus (GFLV) in grape rootstocks. Six transgenic rootstock genotypes expressing various gene constructs derived from the GFLV genome have been developed. Some of them have been characterized for transgene integration and expression. Plants have been established in a GFLV-free block in California. Cutting from these plants have been propagated. They will be established shortly in a naturally GFLV-infected vineyard site to evaluate the level of resistance against virus infection in the presence of the nematode vector.

My research is expected to substantially benefit the grape and wine industry. It is anticipated that the use of GFLV-resistant rootstocks will allow growers to rely less on toxic agrochemicals to eradicate nematode vector populations. Our efforts should also increase the income of grape growers and enhance opportunities for high quality and sustainable viticulture.

Plant virology