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ARS Home » Pacific West Area » Pullman, Washington » Grain Legume Genetics Physiology Research » Research » Publications at this Location » Publication #325370
Title: Characterization of the mycelial compatibility groups and mating type alleles in populations of Sclerotinia minor in central China

Author
item YANG, D - Huazhong Agricultural University
item ZHANG, J - Huazhong Agricultural University
item WU, M. - Huazhong Agricultural University
item Chen, Weidong
item LI, GUOQING - Huazhong Agricultural University
item YANG, LONG - Huazhong Agricultural University

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/26/2016
Publication Date: 10/27/2016
Citation: Yang, D., Zhang, J., Wu, M., Chen, W., Li, G., Yang, L. 2016. Characterization of the mycelial compatibility groups and mating type alleles in populations of Sclerotinia minor in central China. Plant Disease. 100:2313-2318.

Interpretive Summary: Sclerotinia species are devastating plant pathogens causing white mold on many economically important crops including cool season legumes. Although S. sclerotiorum has been intensively studied, S. minor gained much less attention, despite causing important diseases on lettuce and peanuts. This study was aimed at gaining further insight into the population biology of S. minor by studying S. minor populations infecting lettuce in central China. Ninety-five isolates were isolated from lettuce in three counties in central China, and their myceial compatibility groups and mating type alleles were investigated. Eight MCGs (MCG 1 to MCG 8) and two MAT alleles (Inv+, Inv-) were identified in these isolates. The S. minor populations in central China had similar low levels of MCG diversity and similar proportions of MAT heterokaryon isolates as those found in USA previously. Additionally, isolates of different MCGs or with different MAT alleles did not significantly differ (P > 0.05) or differed slightly in mycelial growth rate and sclerotial yield, and lesion diameters on lettuce leaves. Additionally, this study found five new host plants of S. minor and identified three hypovirulent isolates. These results broadened our understanding about the population biology of S. minor and might be useful for developing novel strategies to managing diseases caused by this pathogen.

Technical Abstract: Ninety-five single-sclerotium isolates were obtained from lettuce and weeds in three counties in central China. They were identified belonging to Sclerotinia minor Jagger based on colony morphology and the S. minor-specific DNA marker. Mycelial compatibility groups (MCGs) and the mating type (MAT) alleles in these isolates were determined using the methods of paired cultures and specific PCR, respectively, and the MCG data were used to calculate Shannon’s H index (H) and Simpson index (S), thereby evaluating diversity of S. minor. Eight MCGs (MCG 1 to MCG 8) and two MAT alleles (Inv+, Inv-) were identified in these isolates. Low diversity was detected for the total 95 isolates based on the MCG data (H = 1.748, S = 0.786). The S. minor populations in central China had similar low levels of MCG diversity and similar proportions of MAT heterokaryon isolates as those found in USA previously. Additionally, isolates of different MCGs or with different MAT alleles did not significantly differ (P > 0.05) or differed slightly in mycelial growth rate and sclerotial yield, and lesion diameters on lettuce leaves. Furthermore, this study found five new host plants of S. minor in China and identified three hypovirulent isolates. These results broadened our understanding about the population biology of S. minor and might be useful for initiating novel strategies to control diseases caused by this pathogen in the future.