DIRECTING POTENTIAL ANTI-XYLELLA GENE PRODUCTS TO THE XYLEM

• Author(s): Dandekar, Abhaya; Meredith, C; Kirkpatrick, Bruce; Labavitch, John;
• Abstract: The purpose of this research was to transform Vitis vinifera cultivars with the pear polygalacturonase inhibiting protein (PGIP) gene in order to analyze its effect in developing resistance to PD in transgenic plants. A second goal was the transformation of grapevine with several green fluorescence protein (GFP) constructs carrying sequences expected to enhance secretion from the cell to evaluate the effect of signal sequences on the targeting of transgene products to xylem tissue. Some of the transgenic lines expressing pgip exhibited reduced PD symptoms, which suggests that Xyllela polygalaturonase might be inhibited in transgenic plants. Tests will be conducted in the future to evaluate the development of PD in the field. We also found that the pear PGIP was secreted into the xylem. This is relevant to PD because X. fastidiosa is a xylem-limited bacteria. It is also very important that the transgene product was observed to move through the graft union and thus is transmitted to the scion, implying that a few transgenic rootstocks could be used with any scion variety. Fluorescence in plants transformed with GFP fused to the signal peptide sequences of tricosanthin and XSP30 was only detected inside the cells. The absence of fluorescence in the apoplast could be related to GFP expression itself instead of failure of TCS and XSP30 signal peptides.
• Publication Date: Aug 2003
• Journal: 2003 Pierce's Disease Research Symposium