Link to home

Cannot retrieve the URL specified in the Content Link property. For more assistance, contact your site administrator.

Lose the effector or die tryin’: Novel quantitative resistance loci for bacterial blight
Alejandra Huerta: Colorado State University; Emily Delorean: Colorado State University; Ana Bossa-Castro: Colorado State University; Chitra Raghavan: International Rice Research Institute; Rene Corral: Colorado State University; Valerie Verdier: IRD, Cirad, Univ Montpellier, IPME; Hei Leung: Intl Rice Research Inst; Jan Leach: Colorado State University
<div>Bacterial blight (BB), caused by <i>Xanthomonas oryzae </i>pv. <i>oryzae </i>(<i>Xoo</i>), is the single most destructive bacterial disease of rice. The optimal agronomic practice to manage the disease is deployment of<i> </i>resistant varieties. However, effective and durable disease resistance for BB is a continuous challenge due to the pathogen’s evolution and adaptation on cultivated varieties. Key to<i> Xoo</i> pathogenicity and virulence are Transcription Activator-Like (TAL) effectors, which activate expression of host susceptibility genes. TAL effectors differently contribute to a strain’s virulence, and some are essential to pathogen fitness. We hypothesize that effective and durable disease resistance is attainable by targeting important virulence factors in the bacterium. To test this hypothesis we took advantage of the <i>indica</i> Multi-Parent Advanced Generation Inter-Cross (MAGIC) inbred lines and screened them for resistance against <i>Xoo</i> strains PXO99A and PXO99A carrying the virulence factor TAL7b (+TAL7b). Transgressive segregation for resistance in the MAGIC lines was observed to both PXO99A and PXO99A +TAL7b, suggesting the presence of resistance for BB. Genome-wide association and interval mapping analysis revealed 13-disease resistance QTL, six specific to PXO99A +TAL7B and seven to PXO99A. The top ranking predicted gene target for TAL7b correlated to a QTL on chromosome 8. Altogether, our data suggest that the TAL7b target is a disease susceptibility gene that contributes to <i>Xoo</i> fitness in rice and that the resistance locus identified may harbor polymorphisms in the TAL7b gene target, disabling activation of the susceptibility gene. Future research will focus on the mechanism underlying this novel resistance phenotype.</div>

View Presentation