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ARS Home » Pacific West Area » Salinas, California » Crop Improvement and Protection Research » Research » Publications at this Location » Publication #410449
Research Project: Disease Management and Improved Detection Systems for Control of Pathogens of Vegetables and Strawberries

Location: Crop Improvement and Protection Research

Title: Characterization of gene expression in Peronospora effusa and spinach during resistant and susceptible race-cultivar interactions

Author
item CLARK, KELLEY - University Of California
item Feng, Chunda
item Anchieta, Amy
item VAN DEYNZE, ALLEN - University Of California
item CORRELL, JAMES - University Of Arkansas
item Klosterman, Steven

Submitted to: Fungal Genetics Conference
Publication Type: Abstract Only
Publication Acceptance Date: 2/9/2024
Publication Date: 3/13/2024
Citation: Clark, K.J., Feng, C., Anchieta, A.G., Van Deynze, A., Correll, J.C., Klosterman, S.J. 2024. Characterization of gene expression in Peronospora effusa and spinach during resistant and susceptible race-cultivar interactions. Fungal Genetics Conference, March 12-17, 2024, Pacific Grove, California.

Interpretive Summary:

Technical Abstract: The obligate oomycete pathogen, Peronospora effusa, causes downy mildew of spinach. Downy mildew disease control is predominantly based on development of resistant spinach cultivars. However, new races and novel isolates of the pathogen continue to emerge and overcome cultivar resistance. Currently there are 19 named races of P. effusa. Here we characterized the transcriptomes of spinach, Spinacia oleracea, and P. effusa during disease progression using the spinach cultivar Viroflay, two near isogenic lines NIL1 and NIL3, and two P. effusa races, R13 and R19, at 24 hours post inoculation and 6 days post inoculation. Differentially expressed gene (DEG) analysis in resistant spinach interactions of R13-NIL3 and R19-NIL1 revealed DEGs from protein kinase-like and P-loop containing families, which have roles in plant defense. Additionally, analysis of the expression of eight DEGs with homology to previously reported downy mildew resistance genes highlighted that some are differentially expressed during resistant spinach-P. effusa reactions but not during the susceptible ones. Examination of P. effusa gene expression during infection of susceptible cultivars identified expressed genes specific to R19 or R13, and included predicted genes encoding RxLR and Crinkler effector genes that may be responsible for race-specific virulence on NIL1 or NIL3 spinach hosts, respectively. These findings provide insight into gene expression in both spinach and P. effusa during susceptible and resistant interactions and provide a library of candidate genes for further exploration and functional analysis. These resources will benefit spinach breeding efforts for disease resistance and increase our understanding of the virulence mechanisms of this obligate pathogen.