Abstract

Fungal pathogens are major problems for grape growers among which the grey mold, caused by Botrytis cinerea, is the most severe and difficult to control in Chile and other viticultural regions of the world. Botrytis can cause economic loss both pre- and post-harvest and even low levels of infection can negatively impact the value of table grapes. A genetic transformation approach was initiated to improve resistance to fungal pathogens three years ago, based on a combination of Trichoderma harzianum anti-fungal genes and anti-microbial peptide genes introduced into selected table grape cultivars including 'Thompson Seedless'. Transformation of embryogenic cultures was initially optimized using GFP and then combinations of antifungal genes were introduced using Agrobacterium-mediated transformation. More than 140 PCR-tested plants are under evaluation. Preliminary evaluations based on inoculation of leaves with Botrytis indicate a significant reduction in lesion size for some of the transgenic lines. After additional characterization of the transgenic lines we plan to evaluate the resistance of selected lines in field trials under isolation conditions.