CucCAP research identifies a cucumber gene for resistances to downy mildew, angular leaf spot and anthracnose

Development of varieties with multiple disease resistances is always an important goal for plant breeders. The plant introduction (PI) line, PI 197087 possesses resistances against the downy mildew (an oomycyte pathogen), the angular leaf spot (a bacterial pathogen) and the anthracnose (a fungal pathogen). These resistances have been widely deployed in commercial cucumber varieties in the US since 1950’s, but the genetic basis of the resistances is still unknown. In a recent study, Dr. Yiqun Weng’s Lab at the Vegetable Crops Research Unit in USDA-ARS, Madison, Wisconsin identified the STAYGREEN gene that is responsible for the PI 197087-derived triple-disease resistances. The STAYGREEN gene has been known to play important regulatory roles in the chlorophyll degradation pathway. Thus, the multiple-disease resistance is a novel function of this gene. This study found that the durable, broad-spectrum disease resistance in cucumber is due to a loss-of-susceptibility mutation in the STAYGREEN gene. Results from this study have been published in the journal of New Phytologist. This work was supported by the USDA-SCRI CucCAP project. Dr. Yuhui Wang, Assistant Research Scientist of the University of Wisconsin at Madison is the leading author of this paper. Dr. Todd Wehner of North Carolina State University, a CucCAP project team member and cucumber industry collaborators also contributed to this research.

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