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ARS Home » Plains Area » Fargo, North Dakota » Edward T. Schafer Agricultural Research Center » Cereal Crops Research » Research » Publications at this Location » Publication #363504

Research Project: Improvement of Biotic Stress Resistance in Durum and Hard Red Spring Wheat Using Genetics and Genomics

Location: Cereal Crops Research

Title: Genetic mapping of the Ph gene conferring disease resistance to black shank in tobacco

item BAO, YINGUANG - Shandong Agricultural University
item DING, NA - University Of Kentucky
item QIN, QIULIN - University Of Kentucky
item WU, XIA - University Of Kentucky
item MARTINEZ, NATALIA - University Of Kentucky
item MILLER, ROBERT - University Of Kentucky
item ZAITLIN, DAVID - University Of Kentucky
item LI, DANDAN - University Of Kentucky
item Yang, Shengming

Submitted to: Molecular Breeding
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/9/2019
Publication Date: 8/16/2019
Citation: Bao, Y., Ding, N., Qin, Q., Wu, X., Martinez, N., Miller, R., Zaitlin, D., Li, D., Yang, S. 2019. Genetic mapping of the Ph gene conferring disease resistance to black shank in tobacco. Molecular Breeding. 39(9):122.

Interpretive Summary: Black shank disease is among the most destructive and widespread of all tobacco diseases in the world. Breeding resistant varieties is one of the best strategies for disease control. However, tobacco breeding for disease resistance to black shank is seriously hampered due to the lack of user-friendly markers, which can precisely predict disease susceptibility. In the present study, we localized the Ph gene conferring disease resistance to black shank on tobacco chromosome 20, and a few markers useful for breeding were also identified. This research provides user-friendly markers that are valuable for tobacco breeders to accelerate breeding process, and genetic localization of the Ph gene benefits biologists to clone this important gene.

Technical Abstract: Black shank, caused by the hemibiotrophic oomycete Phytophthora parasitica var. nicotianae, is one of the most destructive tobacco diseases. Using host resistance is the most environmentally friendly and sustainable strategy for reducing potential crop losses from blue shank disease. To assist breeding for black shank resistance and to facilitate gene cloning, we genetically mapped and characterized the Ph gene that confers resistance to P. parasitica var. nicotianae race 0. The Ph gene, which originated in N. plumbaginifolia, was found to be located on the top of LG20 in a genomic region that is enriched with genes coding for receptor-like-kinases. Expression analysis of pathogen-related (PR) genes revealed that the hypersensitive response (HR) was induced rapidly in resistant plants at the biotrophic infection stage, while in susceptible lines, an intensified HR-like reaction was activated during necrotrophy. The genotype race-specific resistance conditioned by the Ph gene may be triggered by recognition of a matching Avirulence (Avr) protein secreted by the pathogen during the early phase of infection. However, pathogen colonization in compatible hosts could be achieved by hijacking of resistance signaling and acquiring nutrients from the dead cells after it switches to necrotrophy.