Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: 7/20/2006
Publication Date: 7/28/2006
Citation: Njambere, E., Chen, W., Frate, C., Temple, S., Muehlbauer, F.J. 2006. Diversity of Sclerotinia isolates from chickpea from central California. Phytopathology 96:S85.
Technical Abstract: Phenotypic and genetic diversity of Sclerotinia isolates collected from chickpea plants showing collar rot symptoms in central California were studied and compared with previously identified isolates of S. sclerotiorum to determine their species identities. Isolates exhibited two growth rates, fast growing (~40 mm diameter in 24 hours) and slow growing (~20 mm diameter in 24 hours). Fast growing isolates showed strong oxalic acid production as detected in a pH indicator medium, whereas slow growing isolates produced little or no oxalic acid on the same medium. PCR was used on representative isolates from each group to detect the presence of an intron near the 3'-end of small subunit rDNA. An intron was detected in the slow growing isolates, but not in the fast growing isolates. PCR with single long primers also produced DNA polymorphisms separating these two groups. The fast growing isolates shared the same attributes of previously identified isolates of S. sclerotiorum. The slow growing isolates showed the reported characteristics of S. trifoliorum. The species identity of these two groups is being tested and confirmed by inducing carpogenic germination of sclerotia.