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Oospore Production of Phytophthora infestans in Potato and Tomato Leaves.
Phytopathology 1997; 87(2):191-6P

Abstract

ABSTRACT

Fungal, host, and environmental factors affecting sexual reproduction of Phytophthora infestans in planta were studied. Intact and detached leaves were coinoculated with sporangia of various combinations of A(1) and A(2) mating-type isolates; leaves were incubated under various conditions, and oospore production was estimated microscopically within whole, clarified leaflets. Some A(1) + A(2) isolate combinations were more reproductive than others, whereas some potato genotypes better supported oospore formation than others. Tomato usually supported more oospore formation than potato. To induce oospore formation, A(1) and A(2) sporangia were usually mixed at a 1:1 ratio. Ratios of 1:19 to 19:1, however, also allowed abundant production of oospores. Optimal temperatures for sexual sporulation ranged from 8 to 15 degrees C, but oospores also were produced at 23 degrees C. Oogonia developed 5 to 6 days after sporangial coinoculation, and oospores developed after 8 to 10 days. Light had little effect on oospore formation in both tomato and potato leaves provided that initial lesions were established under photoperiodic conditions. Although A1 and A(2) sporangia usually were mixed before inoculation on leaves to obtain oospores, we found that discrete A(1) and A(2) lesions produced on opposite sides of the midvein of tomato leaves also induced oospore formation in the midvein and adjacent tissues. Oospores also formed when the two halves of the leaves were cut and separated at 3 days after sporangial coinoculation, which corresponded with the appearance of late blight lesions. The continuous supply of moisture to infected leaves was essential to oospore production. No oospores or oogonia formed in severely diseased plants kept at 50 to 80% relative humidity. Such plants did allow some oospore formation when kept continuously wet for 2 weeks in plastic boxes or tents. Detached leaves floated on water supported the highest sexual sporulation. Under optimal conditions of wetness and temperature, as many as 100 oospores per mm(2) of tissue were observed.

Authors

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Pub Type(s)

Journal Article

Language

eng

PubMed ID

18945141

Citation

Cohen, Y, et al. "Oospore Production of Phytophthora Infestans in Potato and Tomato Leaves." Phytopathology, vol. 87, no. 2, 1997, pp. 191-6.
Cohen Y, Farkash S, Reshit Z, et al. Oospore Production of Phytophthora infestans in Potato and Tomato Leaves. Phytopathology. 1997;87(2):191-6.
Cohen, Y., Farkash, S., Reshit, Z., & Baider, A. (1997). Oospore Production of Phytophthora infestans in Potato and Tomato Leaves. Phytopathology, 87(2), pp. 191-6.
Cohen Y, et al. Oospore Production of Phytophthora Infestans in Potato and Tomato Leaves. Phytopathology. 1997;87(2):191-6. PubMed PMID: 18945141.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Oospore Production of Phytophthora infestans in Potato and Tomato Leaves. AU - Cohen,Y, AU - Farkash,S, AU - Reshit,Z, AU - Baider,A, PY - 1997/2/1/pubmed PY - 1997/2/1/medline PY - 1997/2/1/entrez SP - 191 EP - 6 JF - Phytopathology JO - Phytopathology VL - 87 IS - 2 N2 - ABSTRACT Fungal, host, and environmental factors affecting sexual reproduction of Phytophthora infestans in planta were studied. Intact and detached leaves were coinoculated with sporangia of various combinations of A(1) and A(2) mating-type isolates; leaves were incubated under various conditions, and oospore production was estimated microscopically within whole, clarified leaflets. Some A(1) + A(2) isolate combinations were more reproductive than others, whereas some potato genotypes better supported oospore formation than others. Tomato usually supported more oospore formation than potato. To induce oospore formation, A(1) and A(2) sporangia were usually mixed at a 1:1 ratio. Ratios of 1:19 to 19:1, however, also allowed abundant production of oospores. Optimal temperatures for sexual sporulation ranged from 8 to 15 degrees C, but oospores also were produced at 23 degrees C. Oogonia developed 5 to 6 days after sporangial coinoculation, and oospores developed after 8 to 10 days. Light had little effect on oospore formation in both tomato and potato leaves provided that initial lesions were established under photoperiodic conditions. Although A1 and A(2) sporangia usually were mixed before inoculation on leaves to obtain oospores, we found that discrete A(1) and A(2) lesions produced on opposite sides of the midvein of tomato leaves also induced oospore formation in the midvein and adjacent tissues. Oospores also formed when the two halves of the leaves were cut and separated at 3 days after sporangial coinoculation, which corresponded with the appearance of late blight lesions. The continuous supply of moisture to infected leaves was essential to oospore production. No oospores or oogonia formed in severely diseased plants kept at 50 to 80% relative humidity. Such plants did allow some oospore formation when kept continuously wet for 2 weeks in plastic boxes or tents. Detached leaves floated on water supported the highest sexual sporulation. Under optimal conditions of wetness and temperature, as many as 100 oospores per mm(2) of tissue were observed. SN - 0031-949X UR - https://www.unboundmedicine.com/medline/citation/18945141/Oospore_Production_of_Phytophthora_infestans_in_Potato_and_Tomato_Leaves_ L2 - http://apsjournals.apsnet.org/doi/full/10.1094/PHYTO.1997.87.2.191?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -