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United States Department of Agriculture

Agricultural Research Service

Research Project: MANAGEMENT OF GENETIC RESOURCES FOR VITIS, PRUNUS, JUGLANS, FICUS, OLEA, PISTACIA, PUNICA, DIOSPYROS, ACTINIDIA, AND MORUS

Location: National Clonal Germplasm Rep - Tree Fruit & Nut Crops & Grapes

Title: Genetic variability in the pistachio late blight fungus, Alternaria alternata

Authors
item Aradhya, Mallikarjuna
item Chan, H. - UCD - PLANT SCIENCE
item Parfitt, D. - UCD - PLANT SCIENCE

Submitted to: Mycological Research
Publication Type: Popular Publication
Publication Acceptance Date: August 27, 2000
Publication Date: March 1, 2001
Citation: Aradhya, M.K., Chan, H., Parfitt, D.E. 2001. Genetic variability in the pistachio late blight fungus, Alternaria alternata. Mycological Research, 105: 300-306.

Interpretive Summary: Genetic variation in the pistachio late blight fungus, Alternaria alternata, was investigated by restriction fragment length polymorphism (RFLP) in the rDNA region. Southern hybridization of EcoRI, HindIII, and Xbal digested fungal DNA with a RNA probe derived from Alt1, an rDNA clone isolated from a genomic library of the Japanese pear pathotype of A. alternata, revealed 34 different rDNA haplotypes among 56 isolates collected from four central valley locations in California. Analysis of molecular variation revealed a significant amount of genetic diversity within populations (85.8%), with only marginal variation accounting for differentiation among populations (14.2%, fST = 0.142). All isolates examined were highly pathogenic. The identity of the four geographic populations sampled was not evident in both cluster and principal component analyses, probably indicating either the selectively neutral nature of rDNA variation or prevalence of widespread gene flow among populations combined with uniform host-selection.

Technical Abstract: Genetic variation in the pistachio late blight fungus, Alternaria alternata, was investigated by restriction fragment length polymorphism (RFLP) in the rDNA region. Southern hybridization of EcoRI, HindIII, and Xbal digested fungal DNA with a RNA probe derived from Alt1, an rDNA clone isolated from a genomic library of the Japanese pear pathotype of A. alternata, revealed 34 different rDNA haplotypes among 56 isolates collected from four central valley locations in California. Analysis of molecular variation revealed a significant amount of genetic diversity within populations (85.8%), with only marginal variation accounting for differentiation among populations (14.2%, fST = 0.142). All isolates examined were highly pathogenic. The identity of the four geographic populations sampled was not evident in both cluster and principal component analyses, probably indicating either the selectively neutral nature of rDNA variation or prevalence of widespread gene flow among populations combined with uniform host-selection.

Last Modified: 9/20/2014
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