Phythophthora Diagnostics


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Phytophthora training Video Horticulture Innoivation Lab

Phytophthora species are responsible for devastating diseases on a wide range of host crops, natural vegetation and forestry worldwide. Species such as P. infestans, P. sojae, P. capsici and P. ramorum cause major losses on potato, soybean, pepper, ornamental and forest tree species. Some species have wide host ranges such as the root pathogen P. cinnamomi which can infect over 3000 host species. Migrations of Phytophthora species in plant materials over large geographic areas have led to some of the most devastating epidemics known to mankind including late blight of potato which spread by migration of infected tubers from South America and sudden oak death (P. ramorum) which has moved repeatedly with the nursery plant trade between continents and across the US.

My lab has deployed a series of “shovel ready” technologies for improving diagnosis of Phytophthora diseases including a Lucid key, a protocols book, molecular and digital diagnostic identification systems and a survey to identify Phytophthora species on cacao, potato and floriculture crops and improve the diagnostic capabilities for important plant disease clinics in the region of Central America ( Costa Rica and Honduras). The Lucid key was released and being sold by APS press. An ultimate goal of this project is to develop a coordinated network of trained extension, local government, and university scientists in plant diagnostic clinics within Central America that will have the tools needed for identifying and controlling Phytophthora diseases, thus reducing importation of new species of Phytophthora into the US. We have started the Latin American Phytophthora Diagnostic Network on Facebook. The diagnostic workshops were held at Universdad de Costa Rica in 2010 and  the Pan American University at Zamarano Honduras in 2013.

The workshop has been expanded globally. A “Rapid Diagnostic Tools for Identification of Phytophthora species on Horticultural Crops ” organized by Dr. Jean Ristaino, with the assistance of Dr. Pallem Chowdappa, ICAR and Dr. David Cooke was held at the ICAR- Central Plantation Crops Research Institute, Bangalore India, Sept 8, 2015 preceding the 3rd International Phytophthora Symposium, Sept 9-12.  Over 120 participants applied for the workshop that included 30 students from diverse research institutes in India. The hands on laboratory training in morphological and molecular identification of Phytophthora species included use of a diagnostic keys, PCR and sequence based identification.DSC09759

North Carolina State University brings new expertise to annual BecA-ILRI Hub workshop

The BecA-ILRI Hub annual workshop on Introduction to Molecular Biology and Bioinformatics (IMBB) kicked off on Monday 9 May 2016 at the ILRI campus in Nairobi. The intensive 11-day workshop attracted 27 participants from national agricultural research systems (NARS) in 11 African countries including Burundi, Cameroon, the Democratic Republic of Congo (DRC), Eritrea, Ethiopia, Ghana, Kenya, Rwanda, Nigeria, South Sudan and Sudan. A Phytophthora Diagnostics component of the IMBB workshop was included.  Click here to read more.

The workbook can be downloaded here.

Lucid Key

The Key to the Common Phytophthora species (Lucid v 3.4) is a matrix-based computerized identification key and includes important morphological and molecular characters that are useful for identification of 55 common species of Phytophthora. A set of 20 features are used to make a correct species identification. Once a culture is obtained, the user enters responses to known character state options into Lucid Player, and the correct species is identified. Illustrations of each character state for a feature are included in the key. The main morphological features included in the key are: asexual structures, sexual structures, and chlamydospore, hyphae, and cultural characteristics. The user can read an illustrated “Fact Sheet” on each species that includes pictures of morphological characters, disease symptoms, host range, and relevant references. A cross-linked glossary of terminology is included in each fact sheet. In addition, a DNA search function that contains a simple search of internal transcribed spacer (ITS) and Barcode of Life (BOL, 5′ end of the cox 1 gene) sequences for each species can be queried. The key was created to provide teachers, diagnosticians, and regulatory personnel with easily accessible tools to distinguish common species in the genus Phytophthora based on a number of important morphological and molecular characteristics. The key is available for purchase from APS PRESS and should provide another useful tool for the identification of members of this destructive group of Oomycete plant pathogens.

The Lucid Key can be purchased from APS Press here.

Read a review published in Fungal Diversity (2013) 59:179–197.

Funding sources:

Ristaino, J. B., Ivors, K., and Harmon, C. 2010. Deployment of Rapid Diagnostic Tools for Phytophthora on horticultural crops in Central America. USAID Hort CRSP. $148,327.

Ristaino, J. B.; 2012. Building Regional Capacity in Phytophthora Diagnostics in Latin America. USAID Hort CRSP, $39,042.