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ARS Home » Research » Publications at this Location » Publication #74692
Title: PATHOGENIC AND MOLECULAR CHARACTERIZATION OF PHOMOPSIS FROM THREE POME AND STONE FRUIT SPECIES IN GEORGIA

Author
item UDDIN, W - UNIVERSITY OF GEORGIA
item REYNOLDS, K - UNIVERSITY OF GEORGIA
item Schultheiss, Rebecca
item REHNER, S - USDA ARS BA PSI SBML

Submitted to: Phytopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/14/1998
Publication Date: N/A
Citation: N/A

Interpretive Summary: Members of the fungal genus Phomopsis cause diseases of a wide range of agricultural crops including fruit trees in Georgia. Species of Phomopsis are not well-defined particularly in regard to pathogenicity. This study demonstrates that strains causing disease on peach and plum can also infect other fruit trees in the Rosaceae such as apples and pears. The strains were studied to determine both their morphological and molecular characteristics. This study will be used by fruit tree pathologists and extension agents in developing control strategies for the diseases caused by the fungus Phomopsis.

Technical Abstract: A species of Phomopsis, causing shoot blight of peach, and two other isolates from necrotic tissues of blighted plum shoots and dead buds of Hosui Asian pear, were evaluated for their pathogenicity on apple, pear, peach and plum. Current year's shoots of 1-year-old Stayman Winesap apple, Barlett pear, Babygold-7 peach and Bruce plum trees were inoculated with each of the isolates by wounding a bud and applying agar block with young hyphae. Cankers developed on shoots of all fruit species inoculated with the peach isolate and peach shoots inoculated with plum and Asian pear isolates. No cankers developed on apple, pear or plum shoots inoculated with plum and Asian pear isolates. The cankers on peach were significantly longer than those on pear, but they were not significantly different from those on plum. Cankers on all four fruit species were significantly different from one another 17 and 24 days after inoculation. There was no significant difference between the length of cankers on peach shoots inoculated with plum and Asian pear isolates, and they were significantly smaller than those inoculated with the peach isolate. None of the control trees developed cankers. The three isolates on potato-dextrose agar differed in colony morphology, and appearance of conidiomata, conidiogenous cells and a-conidia. Multi-locus DNA fingerprint analysis and ITS sequence comparisons revealed similarities between the plum and Asian pear isolates but a significant difference between these two and the peach isolate. The results indicated that the Phomopsis sp. that causes shoot blight of peach has the potential to cause disease on other stone and pome fruits, and peach may also be susceptible to other species of Phomopsis associated with different fruit tree hosts.