Tracing the Course of an Introduced Pathogen: Population Biology of Fusarium circinatum and Epidemiology of Pitch Canker DiseaseEPA Grant Number: U915136
Title: Tracing the Course of an Introduced Pathogen: Population Biology of Fusarium circinatum and Epidemiology of Pitch Canker Disease
Investigators: Wikler, Karen
Institution: University of California - Berkeley
EPA Project Officer: Manty, Dale
Project Period: January 1, 1997 through January 1, 2000
Project Amount: $102,000
RFA: STAR Graduate Fellowships (1997) RFA Text | Recipients Lists
Research Category: Fellowship - Pathology , Academic Fellowships , Health Effects
The overall objective of this research project is to gain insight into the epidemiology of pitch canker in California and the population biology of the exotic fungus responsible for this disease of coastal pine trees. The specific objectives of this research project are to: (1) preliminarily assess global genetic relationships of Fusarium circinatum; (2) determine if the fungus has the potential to undergo sexual recombination in California; and (3) study the development of pitch canker in native and urban pine forests.
By most standard assessments of intraspecies diversity, F. circinatum appears to be a very tight phylogenetic group. To enhance the likelihood of identifying informative markers, a library of DNA fragments generated by Restriction Fragment Length Polymorphism subtraction was screened for polymorphisms by probing Hind III digested F. circinatum DNA. Eight fragments that yielded polymorphisms were chosen as markers. The allele types of 33 California isolates were assessed at each of the eight different loci identified by the markers. To compare the genetic diversity within California with the population at large, isolates from the southeastern United States, Mexico, Japan, and South Africa also have been included in the study. To determine the fertility of the California population, representative isolates from each vegetative compatibility group were crossed, and offspring were analyzed for evidence of recombination. Viability and virulence assays also were performed with the progeny. To monitor the spread of the disease, 47 permanent plots have been established in four landscape types on the Monterey Peninsula: wild, golf course, light urban, and urban. The plots will be surveyed periodically for the incidence and distribution of pitch canker. Within each plot, the growth rate and needle quality will be monitored, and the incidence of western gall rust, dwarf mistletoe, red turpentine beetle, and pitch moth will be recorded to evaluate the influence of these factors on the development of pitch canker. Data on seedling survival and tree mortality will be collected, allowing for an analysis of age structure and the potential for regeneration.