Journal article
Stem and Crown Rot of Chickpea in California Caused by Sclerotinia trifoliorum
Plant disease, Vol.92(6), pp.917-922
06/2008
Handle:
https://hdl.handle.net/2376/101562
PMID: 30769722
Abstract
The identities of Sclerotinia isolates obtained from chickpea plants showing stem and crown rot were determined using morphological characteristics, variations in group I introns, and internal transcribed spacer (ITS) sequences. Isolates could be separated into two groups based on growth rates at 22°C, fast growing (about 40 mm per day) versus slow growing (about 20 mm per day). All fast-growing isolates induced stronger color change of a pH-indicating medium than did slow-growing isolates at 22°C. The slow-growing isolates contained at least one group I intron in the nuclear small subunit rDNA, whereas all fast-growing isolates lacked group I introns in the same DNA region. ITS sequences of the slow-growing isolates were identical to sequences of Sclerotinia trifoliorum. Those of the fast-growing isolates were identical to sequences of S. sclerotiorum. Finally, the slow-growing isolates showed ascospore dimorphism, a definitive character of S. trifoliorum, whereas the fast-growing isolates showed no ascospore dimorphism. Isolates of both species were pathogenic on chickpea and caused symptoms similar to those observed in the field. This study not only associated the differences between S. sclerotiorum and S. trifoliorum in growth rates, group I introns, ITS sequences, and ascospore morphology, but also represented the first report that S. trifoliorum causes stem and crown rot of chickpea in North America.
Chickpea stem rot can be caused by three Sclerotinia spp.: Sclerotinia minor, S. sclerotiorum, and S. trifoliorum. S. sclerotiorum is the common cause of chickpea stem rot world wide. In North America, both S. minor and S. sclerotiorum are reported to cause stem rot of chickpea. S. trifoliorum, along with S. sclerotiorum, previously was reported to occur on chickpea only in Australia. During investigation of Sclerotinia stem rot of chickpea in central California, isolates showed obviously different characteristics that indicated that different species were involved. This research was conducted to determine the species identities of Sclerotinia isolates obtained from chickpea plants showing stem and crown rot, using cultural, morphological, and molecular characteristics. Previously described characteristics differentiating S. trifoliorum from S. sclerotiorum (growth rate and variations in group I introns and internal transcribed spacer sequences) were associated with the definitive morphological character of ascospore dimorphism on the same set of isolates from chickpea from California, showing for the first time that S. trifoliorum causes crown and stem rot of chickpea in North America. S. trifoliorum is a common pathogen of forage legumes such as alfalfa; therefore, the results implicate disease management decisions in choosing rotational crops and in selecting chickpea production fields.
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Details
- Title
- Stem and Crown Rot of Chickpea in California Caused by Sclerotinia trifoliorum
- Creators
- Evans N Njambere - Washington State University, PullmanWeidong Chen - United States Department of Agriculture–Agricultural Research Service (USDA-ARS), Grain Legume Genetics and Physiology Research, Washington State University, PullmanCarol Frate - University of California-DavisBo-Ming Wu - University of California-DavisSteve R Temple - University of California-DavisFred J Muehlbauer - USDA-ARS, Grain Legume Genetics and Physiology Research, Washington State University, Pullman
- Publication Details
- Plant disease, Vol.92(6), pp.917-922
- Academic Unit
- Crop and Soil Sciences, Department of; Plant Pathology, Department of
- Identifiers
- 99900546654801842
- Language
- English
- Resource Type
- Journal article