title: Genetic Architecture of Resistance toAlternaria brassicaeinArabidopsis thaliana: QTL Mapping Reveals Two Major Resistance-Conferring Loci.
abstract: Alternaria brassicae, a necrotrophic fungal pathogen, causesAlternariablight, one of the most important diseases of oleiferousBrassicacrops. The current study utilizedArabidopsisas a model to decipher the genetic architecture of defense againstA. brassicae. Significant phenotypic variation that was largely genetically determined was observed amongArabidopsisaccessions in response to pathogen challenge. Three biparental mapping populations were developed from three resistant accessions viz. CIBC-5, Ei-2, and Cvi-0 and two susceptible accessions - Gre-0 and Zdr-1 (commonly crossed to CIBC-5 and Ei-2). A total of six quantitative trait locus (QTLs) governing resistance toA. brassicaewere identified, five of which were population-specific while one QTL was common between all the three mapping populations. Interestingly, the common QTL had varying phenotypic contributions in different populations, which can be attributed to the genetic background of the parental accessions. The presence of both common and population-specific QTLs indicate that resistance toA. brassicaeis quantitative, and that different genes may mediate resistance to the pathogen in different accessions. Two of the QTLs had moderate-to-large effects, one of which explained nearly 50% of the variation. The large effect QTLs may therefore contain genes that could play a significant role in conferring resistance even in heterologous hosts.
authors.affiliation: Department of Genetics, University of Delhi South Campus New Delhi, India.
authors.forename: Sivasubramanian
authors.initials: S
authors.lastname: Rajarammohan
authors.affiliation: Department of Genetics, University of Delhi South Campus New Delhi, India.
authors.forename: Amarendra
authors.initials: A
authors.lastname: Kumar
authors.affiliation: Centre for Genetic Manipulation of Crop Plants, University of Delhi South Campus New Delhi, India.
authors.forename: Vibha
authors.initials: V
authors.lastname: Gupta
authors.affiliation: Department of Genetics, University of Delhi South CampusNew Delhi, India; Centre for Genetic Manipulation of Crop Plants, University of Delhi South CampusNew Delhi, India.
authors.forename: Deepak
authors.initials: D
authors.lastname: Pental
authors.affiliation: Department of Genetics, University of Delhi South CampusNew Delhi, India; Centre for Genetic Manipulation of Crop Plants, University of Delhi South CampusNew Delhi, India.
authors.forename: Akshay K
authors.initials: AK
authors.lastname: Pradhan
authors.affiliation: Department of Genetics, University of Delhi South Campus New Delhi, India.
authors.forename: Jagreet
authors.initials: J
authors.lastname: Kaur
keywords: Alternaria brassicae; Arabidopsis; QTL mapping; defense response; disease resistance; necrotroph