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United States Department of Agriculture

Agricultural Research Service

Research Project: Production Management Research For Horticultural Crops in the Gulf South

Location: Southern Horticultural Research

Title: Phytophthora mississippiae sp. nov., a new species recovered from irrigation reservoirs at a plant nursery in Mississippi

Authors
item Yang, Xiao -
item Copes, Warren
item Hong, Chuanxue -

Submitted to: Journal of Plant Pathology & Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 18, 2013
Publication Date: June 24, 2013
Repository URL: http://handle.nal.usda.gov/10113/57134
Citation: Yang, X., Copes, W.E., Hong, C. 2013. Phytophthora mississippiae sp. nov., a new species recovered from irrigation reservoirs at a plant nursery in Mississippi. Journal of Plant Pathology & Microbiology. 4:180 doi:10.4172/2157.7471 1000180.

Interpretive Summary: A previously unknown Phytophthora species was recovered from irrigation water in Mississippi. Since many Phytophthora species are destructive plant pathogens, it is important to identify potential threats to plant production. A physical description of the fungus-like organism was made, growth rates were measured from 9 to 104°F and it was genetically compared to other Phytophthora species. Based on the morphological, physiological and phylogenetic features, this new species is described as Phytophthora mississippiae sp. nov. This information will allow the organism to be formally identified when researchers, crops advisors and extension specialists sample for potential pathogens in ponds used to irrigate commercial ornamental plant nursery crops.

Technical Abstract: A previously unknown Phytophthora species was recovered from irrigation water in Mississippi. This novel species produced both nonpapillate and semipapillate sporangia, and catenulate hyphal swellings. All examined isolates were compatibility type A1. Ornamented oogonia with amphigynous antheridia and plerotic oospores were produced when this novel species was paired with A2 mating type testers of P. cryptogea and P. nicotianae in polycarbonate membrane tests. Sequence analyses of the rDNA internal transcribed spacer (ITS) region and the mitochondrially encoded cytochrome c oxidase 1 (cox 1) gene placed this species in clade 6 of the genus Phytophthora. Based on the morphological, physiological and molecular features, this new species is named as Phytophthora mississippiae sp. nov. The implications of these results are discussed.

Last Modified: 4/17/2014
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