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United States Department of Agriculture

Agricultural Research Service

Research Project: Developing Sustainable Cropping Systems to Improve Water Productivity and Protect Water and Soil Quality in Irrigated Agriculture

Location: Water Management Research

Title: Identification, detection and quantification of Pythium species causing root rot of calla lily in California

Authors
item Li, Wei -
item Hanson, Bradley -
item Gerik, James

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: May 12, 2014
Publication Date: N/A

Technical Abstract: In Monterey and Santa Cruz countries of California, hybrid calla lilies are highly limited by soilborne pathogens, particularly Pythium species. Fifty samples were collected from heavily infected calla lily roots from at least six field sets respectively in 2010 and 2013. Pathogens were isolated from the roots and pathogenicity tests were conducted in the greenhouse. To identify the pathogenic species of Pythium, PCR-RFLP was performed to amplify a portion of the mitochondrial encoded cytochrome oxidase II gene (cox II) and the spacer region between cox I and cox II following enzyme digestion. Based on digestion patterns, PCR products were selected for sequencing. Twenty eight of thirty five in 2010, and fourteen of fifteen in 2013 highly matched the sequence of P. sylvaticum. Only one isolate in 2013 showed sequence similar to P. ultimum. Corresponding to pathogenicity test, isolates similar to P. sylvaticum caused serious diseases and P. ultimum caused mild disease. Morphological characterizations of pathogenic species of Pythium were also observed. Based on the sequences of Pythium species, we designed real time PCR (qPCR) primers which can be specifically used to detect and quantify pathogenic Pythium species in soil. Knowing the pathogen population in soil will help growers make decisions on field selection and soil fumigation before planting calla lily.

Last Modified: 8/27/2014
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