Detecting durable resistance to rice bacterial blight
Date
2016
Authors
Delorean, Emily Elizabeth, author
Leach, Jan, advisor
Verdier, Valerie, committee member
Argueso, Cris, committee member
Brick, Mark, committee member
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Abstract
The productivity of rice, a staple crop worldwide, is limited by pathogens such as Xanthomonas oryzae pv oryzae (Xoo). Controlling yield loss to the resulting disease, bacterial blight, is most effective through growing genetically pathogen resistant rice varieties. However, widespread deployment of varieties containing single gene resistance to bacterial blight places an immense selection pressure on Xoo to evolve virulence. The major virulence factors employed by Xoo to drive infection are transcription activator like (TAL) effectors. TAL effectors are secreted into the host cells where they target the transcription of particular host susceptibility genes to favor infection. Previous TAL effector research indicates that not all TALs are created equal and some are crucial to the virulence of Xoo. By breeding for resistance genes targeting necessary TAL effectors we may find more durable resistance as selection pressure on the pathogen will result in loss of the TAL effector function and therefore a decrease in virulence and pathogen fitness. In the present study, we characterized a novel and widespread TAL effector through quantitative trait loci (QTL) mapping. We used the indica rice Multi-Parent Advanced Generation Inter-Cross (MAGIC) population to screen for resistance to the cloned TAL effector, TAL7b, and the Philippine race 6 Xoo strain PXO99A. Our results confirm that TAL7b is a virulence enhancing factor and that the MAGIC population contains six loci targeting resistance to TAL7b.We also identified another seven resistance QTL to the highly virulent Xoo strain, PXO99A.
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Subject
interval mapping
rice
Xanthomonas oryzae
R genes
genome wide association
TAL effectors