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Characterization of Colletotrichum acutatum Isolates Causing Anthracnose of Almond and Peach in California.
Phytopathology 1997; 87(9):979-87P

Abstract

ABSTRACT

The causal organism responsible for the recent outbreak of almond and peach anthracnose in California was identified and characterized as Colletotrichum acutatum. Isolates of C. acutatum from almond were found to be similar to California strawberry isolates and South Carolina peach and apple isolates of C. acutatum based on conidial morphology, temperature relationships, fungicide sensitivity, and polymerase chain reaction (PCR) methods using DNA species-specific primers. On almond, blossoms and immature or mature fruit were affected by the disease, causing direct losses of crop. On peach, the disease was observed only on mature fruit. Pathogenicity of almond and peach isolates of C. acutatum was demonstrated on wound- and nonwound-inoculated almond or peach fruit by fulfilling Koch's postulates. Conidial morphology of isolates was variable, depending on the medium or substrate used to culture the isolates. Isolates of C. acutatum from strawberry, almond, and peach were grouped together based on a similar response to temperature, with an optimal growth rate at 25 degrees C (generally less than 10 mm/day), whereas isolates of C. gloeosporioides from citrus and papaya had an optimal growth rate at 30 degrees C (generally greater than 10 mm/day). In fungicide disk assays, isolates of C. acutatum from strawberry, peach, and apple, as well as almond and peach isolates from California, were less sensitive to benomyl at 300, 600, or 1,200 mug/ml. In contrast, C. gloeosporioides isolates from citrus and papaya were very sensitive to benomyl at all concentrations evaluated. All isolates of both species were sensitive to captan (300, 600, or 1,200 mug/ml). Oligonucleotide primers were synthesized for C. acutatum, C. fragariae, or C. gloeosporioides using published DNA sequences from the internal transcribed spacer 1 region of ribosomal DNA. Thirty-two Colletotrichum isolates from almond fruit produced DNA products with a C. acutatum primer (CaInt-2) that matched products and approximate molecular weight of known C. acutatum isolates. No PCR products were produced with primers for C. gloeosporioides or C. fragariae. Isolates from citrus and papaya produced DNA products only with primers from C. gloeosporioides or C. fragariae. Thus, worldwide, anthracnose of almonds may be caused by either C. gloeosporioides, as previously reported, or by C. acutatum, as indicated in this study.

Authors

No affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

18945071

Citation

Adaskaveg, J E., and R J. Hartin. "Characterization of Colletotrichum Acutatum Isolates Causing Anthracnose of Almond and Peach in California." Phytopathology, vol. 87, no. 9, 1997, pp. 979-87.
Adaskaveg JE, Hartin RJ. Characterization of Colletotrichum acutatum Isolates Causing Anthracnose of Almond and Peach in California. Phytopathology. 1997;87(9):979-87.
Adaskaveg, J. E., & Hartin, R. J. (1997). Characterization of Colletotrichum acutatum Isolates Causing Anthracnose of Almond and Peach in California. Phytopathology, 87(9), pp. 979-87. doi:10.1094/PHYTO.1997.87.9.979.
Adaskaveg JE, Hartin RJ. Characterization of Colletotrichum Acutatum Isolates Causing Anthracnose of Almond and Peach in California. Phytopathology. 1997;87(9):979-87. PubMed PMID: 18945071.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Characterization of Colletotrichum acutatum Isolates Causing Anthracnose of Almond and Peach in California. AU - Adaskaveg,J E, AU - Hartin,R J, PY - 2008/10/24/pubmed PY - 2008/10/24/medline PY - 2008/10/24/entrez SP - 979 EP - 87 JF - Phytopathology JO - Phytopathology VL - 87 IS - 9 N2 - ABSTRACT The causal organism responsible for the recent outbreak of almond and peach anthracnose in California was identified and characterized as Colletotrichum acutatum. Isolates of C. acutatum from almond were found to be similar to California strawberry isolates and South Carolina peach and apple isolates of C. acutatum based on conidial morphology, temperature relationships, fungicide sensitivity, and polymerase chain reaction (PCR) methods using DNA species-specific primers. On almond, blossoms and immature or mature fruit were affected by the disease, causing direct losses of crop. On peach, the disease was observed only on mature fruit. Pathogenicity of almond and peach isolates of C. acutatum was demonstrated on wound- and nonwound-inoculated almond or peach fruit by fulfilling Koch's postulates. Conidial morphology of isolates was variable, depending on the medium or substrate used to culture the isolates. Isolates of C. acutatum from strawberry, almond, and peach were grouped together based on a similar response to temperature, with an optimal growth rate at 25 degrees C (generally less than 10 mm/day), whereas isolates of C. gloeosporioides from citrus and papaya had an optimal growth rate at 30 degrees C (generally greater than 10 mm/day). In fungicide disk assays, isolates of C. acutatum from strawberry, peach, and apple, as well as almond and peach isolates from California, were less sensitive to benomyl at 300, 600, or 1,200 mug/ml. In contrast, C. gloeosporioides isolates from citrus and papaya were very sensitive to benomyl at all concentrations evaluated. All isolates of both species were sensitive to captan (300, 600, or 1,200 mug/ml). Oligonucleotide primers were synthesized for C. acutatum, C. fragariae, or C. gloeosporioides using published DNA sequences from the internal transcribed spacer 1 region of ribosomal DNA. Thirty-two Colletotrichum isolates from almond fruit produced DNA products with a C. acutatum primer (CaInt-2) that matched products and approximate molecular weight of known C. acutatum isolates. No PCR products were produced with primers for C. gloeosporioides or C. fragariae. Isolates from citrus and papaya produced DNA products only with primers from C. gloeosporioides or C. fragariae. Thus, worldwide, anthracnose of almonds may be caused by either C. gloeosporioides, as previously reported, or by C. acutatum, as indicated in this study. SN - 0031-949X UR - https://www.unboundmedicine.com/medline/citation/18945071/Characterization_of_Colletotrichum_acutatum_Isolates_Causing_Anthracnose_of_Almond_and_Peach_in_California_ L2 - http://apsjournals.apsnet.org/doi/full/10.1094/PHYTO.1997.87.9.979?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -