Breeding PIerce's Disease Resistant Winegrapes

PIs: Andrew Walker, Summaira Riaz

Reports:

• Progress report submitted on 2010-02-28
• Progress report submitted on 2010-02-28
• Renewal report submitted on 2010-02-28
• Progress report submitted on 2009-08-17
• Progress report submitted on 2009-08-17
• Progress report submitted on 2009-03-13
• Progress report submitted on 2008-08-05
• Progress report submitted on 2008-03-24

Research Papers

• Comparative Analysis of ESTs Involved in Grape Responses to Xylella fastidiosa Infection
  Background: The gram-negative bacterium Xylella fastidiosa (Xf) is the causal agent of Pierce's disease (PD) in grape as well as diseases of many fruit and ornamental plants. The current molecular breeding efforts have identified genetic basis of PD resistance in grapes. However, the transcriptome level characterization of the host response to this pathogen is lacking. Results: Twelve tissue specific subtractive suppression hybridization (SSH) cDNA libraries derived from a time course sampling scheme were constructed from stems, leaves and shoots of PD resistant and susceptible sibling genotypes (V. rupestris x V. arizonica) in response to Xf infection. A total of 5,794 sequences were obtained from these cDNA libraries from which 993 contigs and 949 singletons were derived. Using Gene Ontology ( GO) hierarchy, the non-redundant sequences were classified into the three principal categories: molecular function (30%), cellular components (9%) and biological processes (7%). Comparative analysis found variations in EST expression pattern between infected and non-infected PD resistant and PD susceptible grape genotypes. Among the three tissues, libraries from stem tissues showed significant differences in transcript quality suggesting their important role in grape-Xylella interaction. Conclusion: This study constitutes the first attempt to characterize the Vitis differential transcriptome associated with host-pathogen interactions from different explants and genotypes. All the generated ESTs have been submitted to GenBank and are also available through our website for further functional studies.
  2007-02-22
  
• Fine-scale genetic mapping of two Pierce's disease resistance loci and a major segregation distortion region on chromosome 14 of grape
  A refined genetic map of chromosome 14, which contains the Pierce's disease (PD) resistance locus, was created from three grape mapping populations. The source of PD resistance in these populations was b43-17, a male form of Vitis arizonica Engelm. that is homozygous resistant. The resistance locus segregated as a single dominant gene and mapped as PdR1a in the F1 selection F8909-17 (9621 population) and as PdR1b in a sibling F1 selection F8909-08 (04190 population). These two full sibs inherited either allele of the Pierce's disease resistance locus from the b43-17 parent, which is homozygous at that locus. The 9621 population consisted of 425 progeny and PdR1a mapped between markers VvCh14-56/VvCh14-02 and UDV095 within a 0.6 cM genetic distance. The 04190 population consisted of 361 progeny and PdR1b mapped between markers VvCh14-02 and UDV095/VvCh14-10 within a 0.4 cM distance. Many of the markers present on chromosome 14 were distorted with an excess of female alleles in the 04190 and 04373 population (developed from a cross of V. vinifera L. F2-35 x 43-17) indicating that potential gametophytic factors are present in this region. Common markers from this region within the 9621 population were not distorted except Scu15. When these markers were compared to V. vinifera-based maps of chromosome 14 they were also distorted suggesting the involvement of gametophytic factors, and prompting the identification of this region as Vitis-segregation distortion region 1 (V-SDR1). The refined genetic maps developed from this study can be used to identify and clone genes that confer resistance to Pierce's disease.
  2008-09-01
  
• Use of SSR markers to assess identity, pedigree, and diversity of cultivated muscadine grapes
  The North American muscadine grape (Museadinia rotundifolia Small) is a valuable source of resistance to powdery mildew [Uncinula necator (Schw.) Burr], root-knot nematode (Meloidogyne Goeldi), dagger nematode (Xiphinema index Thorne and Allen), grape phylloxera (Daktulosphaira vitifoliae Fitch), and Pierce's disease (Xylella fastidiosa Wells et al.). Efforts to breed muscadine grapes commenced in the early 1900s and have generated a large number of cultivars and a limited number of hybrids with Vitis vinifera L. and other Vitis L. species. Collections of this germplasm are currently maintained with accession identity based on declared identity when collected, breeding records, and comparisons of morphological traits. This study reports on the first use of DNA-based simple sequence repeat (SSR) marker profiles to authenticate M. rotundifolia cultivars and hybrids. A total of 57 accessions [39 M. rotundifolia cultivars, 3 V. vinifera cultivars, 3 Vitis spp. hybrids, and 12 V. vinifera X M. rotundifolia (VR) hybrids] from collections at the U.S. Department of Agriculture National Clonal Germplasm Repository and the University of California (Davis) Department of Viticulture and Enology were analyzed with 14 SSR markers. The fingerprint profiles were used to verify published breeding records of 31 M. rotund folia cultivars and hybrids by comparing the shared alleles of parents and progeny. Marker data indicated that four cultivars were incorrectly identified; their alleles did not match respective parent/progeny relationships at more than five loci. Two M. rotundifolia accessions had the same fingerprint profile as a third accession at all 14 markers, implicating a likely planting error. The M. rotundifolia cultivars exhibited 88 unique alleles that were not present in a database of more than 600 V. vinifera cultivars.
  2008-07-01
  
• Scanning electron Microscopy reveals different response pattern of four Vitis genotypes to Xylella fastidiosa infection
  The xylem-limited bacterium Xylella fastidiosa causes Pierce's disease (PD), whose disease symptoms are primarily the result of xylem vessel blockage in susceptible grapevines. Stein internode and petiole tissues from infected and uninfected control plants of four grape genotypes (Vitis vinifera, V. rufotomentosa, V. smalliana, and V. arizonica/candicans) differing in PD susceptibility were examined using scanning electron microscopy (SEM). Tyloses, fibrillar networks, and gum plugs were observed in lumens of tracheary elements in petioles and internodes of both water-inoculated control plants and X. fastidiosa-inoculated plants of all genotypes. Bacteria were not observed in control plants. In both petiole and internode tissues, the greatest number of occluded xylem vessels were observed in V. vinifera and the smallest number in V arizonica/candicans. The number of xylem vessels infested with X. fastidiosa was greatest in V vinifera and did not differ among the other three genotypes. Systemic infection was found in all genotypes. The frequency with which X. fastidiosa infested vessels were observed using SEM corresponded well with bacterial levels estimated by enzyme-linked immunosorbent assay. Among infected plants, tylose formation in internodes was lowest in V. arizonica/candicans and did not differ among the other three genotypes. Infection with X. fastidiosa strongly induced tylose formation in V. vinifera and V. smalliana but not in V. arizonica/candicans. Analysis across tissues and genotypes indicated an induction of fibrillar networks and gum occlusions in response to X. fastidiosa infection, whereas treatment comparisons within genotypes were not significant except for V. vinifera petioles. Limiting the spread of X. fastidiosa infection by xylem conduit occlusions does not appear to be the mechanism conferring PD resistance or tolerance to V. arizonica/candicans, V smalliana, or V. rufotomentosa. In contrast, the strong induction of tyloses may be detrimental rather than beneficial for V. vinifera survival after X. fastidiosa infection.
  2008-02-01
  
• Xylella fastidiosa population dynamics in grapevine genotypes differing in susceptibility to Pierce's disease
  The xylem-limited bacterium Xylella fastidiosa is the causal agent of Pierce's disease (PD) in grapevines, for which breeding resistant cultivars will be a long-term management strategy that involves the identification and characterization of resistant germplasm. A genetically diverse group of grape species and selections was mechanically inoculated with X. fastidiosa, grown in a greenhouse for 113 days after inoculation, and evaluated for the levels of bacterial concentrations in stem and leaf tissues by quantitative enzyme-linked immunosorbent assay (ELISA). Concentrations of X. fastidiosa were affected by genotype, plant tissue, position on the plant relative to the point of inoculation, and interactions among these factors. Based on estimated concentrations of X. fastidiosa in stem samples at 113 d postinoculation, 9621-67, Muscadinia rotundifolia, Vitis arizonica/candicans, V arizonica/girdiana, V candicans, V girdiana, V nesbittiana, and V shuttleworthii were resistant to PD. In contrast, V vinifera, V aestivalis, 9621-94, and V champinii had very high X. fastidiosa concentrations in stem tissues. Sequential sampling of leaf blades at 34, 77, and 113 d postinoculation revealed different temporal patterns in X. fastidiosa concentrations among the grape genotypes. Estimates of X.fastidiosa concentrations decreased after the first sampling in M. rotundifolia, 9621-67, V girdiana, and V arizonica/candicans but increased in all other genotypes. The characterization of X. fastidiosa concentrations in a broad range of grape genotypes allows for the selection of promising genetic backgrounds capable of greatly limiting the population size and development of X. fastidiosa in stems, a critical trait in the breeding of PD-resistant grapevines.
  2007-01-01
  
• VitisExpDB: A database resource for grape functional genomics
  Background: The family Vitaceae consists of many different grape species that grow in a range of climatic conditions. In the past few years, several studies have generated functional genomic information on different Vitis species and cultivars, including the European grape vine, Vitis vinifera. Our goal is to develop a comprehensive web data source for Vitaceae. Description: VitisExpDB is an online MySQL-PHP driven relational database that houses annotated EST and gene expression data for V. vinifera and non-vinifera grape species and varieties. Currently, the database stores similar to 320,000 EST sequences derived from 8 species/hybrids, their annotation ( BLAST top match) details and Gene Ontology based structured vocabulary. Putative homologs for each EST in other species and varieties along with information on their percent nucleotide identities, phylogenetic relationship and common primers can be retrieved. The database also includes information on probe sequence and annotation features of the high density 60-mer gene expression chip consisting of similar to 20,000 non-redundant set of ESTs. Finally, the database includes 14 processed global microarray expression profile sets. Data from 12 of these expression profile sets have been mapped onto metabolic pathways. A user-friendly web interface with multiple search indices and extensively hyperlinked result features that permit efficient data retrieval has been developed. Several online bioinformatics tools that interact with the database along with other sequence analysis tools have been added. In addition, users can submit their ESTs to the database. Conclusion: The developed database provides genomic resource to grape community for functional analysis of genes in the collection and for the grape genome annotation and gene function identification. The VitisExpDB database is available through our website http://cropdisease.ars.usda.gov/vitis_at/main-page.htm.
  2008-02-28
  

Funding sources:

• Funded by: CDFA PD/GWSS Board
• Budget: $208,000.00
• Start date: 2003-07-01
• Stop date: 2008-06-30
• Status: APPROVED

• Funded by: CDFA PD/GWSS Board
• Budget: $380,410.00
• Start date: 2004-01-01
• Stop date: 2007-01-01
• Status: APPROVED