ARS | Publication request: CHARACTERIZATION AND IDENTIFICATION OF PIERCE'S DISEASE RESISTANCE MECHANISMS: ANALYSIS OF XYLEM ANATOMICAL STRUCTURES AND OF NATURAL PRODUCTS IN XYLEM SAP AMONG VITIS

Submitted to: CDFA Pierce's Disease Control Program Research Symposium
Publication Type: Proceedings
Publication Acceptance Date: October 12, 2004
Publication Date: December 7, 2004
Citation: Lin, H., Walker, A. 2004. Characterization and identification of Pierce's Disease resistance mechanisms: Analysis of xylem anatomical structures and of natural products in xylem sap among Vitis. Proceeding of CDFA Pierce's Disease Control Program Research Symposium. p. 22-24

Interpretive Summary: This research tests the hypothesis that PD resistance is due to the presence of chemical factors, e.g. anti-microbial compounds, expressed in the xylem sap that suppress Xylella fastidiosa and / or anatomical features of the xylem, e.g. pit membranes, that restrict Xf mobility. A wide range of PD resistance from various genetic backgrounds of Vitis species were selected for this study. To test structurally-related pathogen movement, an inter-grafting method was used to measure the movement of Xf across between PD susceptible and resistant stems. Scanning electron microscopy and quantitative PCR are being used in this study. Currently, we conducting in vitro bioassay to exam the xylem saps collected from PD resistant Vitis species.

Technical Abstract: This research tests the hypothesis that PD resistance is due to the presence of chemical factors, e.g. anti-microbial compounds, expressed in the xylem sap that suppress Xylella fastidiosa and / or due to anatomical features of the xylem, e.g. pit membrane, that restrict Xf mobility in the xylem. We selected PD resistant species from various genetic backgrounds of Vitis for this study (V. arizonica, V. aestivalis, V. candicans, V. champinii, V. labrusca, M. munsoniana, V. riparia, M. rotundifolia, V. rufotomentosa, V. shuttleworthii, V. simpsonii, V. smalliana, V. tiliifolia, and V. vulpine). To test structurally related pathogen movement, an inter-grafting method was used to measure the movement of Xf across between PD susceptible and resistant stems. Scanning electro-microscopy was used to characterize the xylem anatomic structures among PD resistant grapes and the quantitative PCR was used for measuring pathogen populations. The preliminary bioassay results indicated that Xylella fastidiosa showed different survival rates in xylem sap from some of resistant genotypes compared to survival in sap from susceptible genotypes.