Cross-infection of subtropical and temperate fruits by Colletotrichum species from various hosts.
Freeman S., Shabi E.
Author Affiliation: Department of Plant Pathology, ARO, The Volcani Center, Bet Dagan 50250, Israel.
Physiological and Molecular Plant Pathology 49 : 395-404
Abstract : Molecular analysis and a pathogenicity assay were used to compare the genetic variability and host specificity of 42 C. gloeosporioides [Glomerella cingulata] isolates from almond, apple, avocado, mango and pecan, and 8 C. acutatum isolates from apple, peach and pecan. PCR amplification of genomic RNA using 4 different primers and HaeIII digestion patterns of genomic DNA (A+T-rich DNA) grouped the C. acutatum isolates separately from those of G. cingulata. Based on arbitrary primed PCR (ap-PCR), intraspecies similarity among the C. acutatum and G. cingulata isolates ranged from 78 to 93% and from 0 to 38%, respectively. Similarity between the C. acutatum and G. cingulata isolates ranged from 0 to 26.5%. A+T-rich DNA grouped the C. acutatum isolates separately from those of G. cingulata isolates, corresponding to ap-PCR analyses. Artificial inoculations with 9 representative isolates on almond, apple, avocado, mango and nectarine fruit showed a variation in infection levels. The G. cingulata isolates from almond grew more slowly, causing significantly smaller lesions on all inoculated fruit than the other isolates. The C. acutatum isolates from apple and peach caused similar levels of infection on all fruit tested, but differed significantly from the G. cingulata isolate from apple. Variation in lesion size was also observed with isolates of G. cingulata from apple, avocado and mango for most fruit inoculations.