QTL Mapping of Web Blotch Resistance in Peanut by High-throughput Genome-wide Sequencing

Abstract

Background: Web blotch is one of the most important foliar diseases worldwide in peanut (Arachis hypogaea L.). The identification of quantitative trait loci (QTLs) for peanut web blotch resistance represents the basis for gene mining and the application of molecular breeding technologies.Results: In this study, a peanut recombinant inbred line (RIL) population was used to map QTLs for web blotch resistance based on high-throughput genome-wide sequencing. Frequency distributions of disease grade and disease index in five environments indicated wide phenotypic variations in response to web blotch among RILs. A high-density genetic map was constructed, containing 3,634 bin markers distributed on 20 peanut linkage groups (LGs) with an average genetic distance of 0.5 cM. In total, eight QTLs were detected for peanut web blotch resistance in at least two environments, explaining from 2.8% to 15.1% of phenotypic variance. Two major QTLs qWBRA04 and qWBRA14 were detected in all five environments and were linked to 40 candidate genes encoding nucleotide-binding site leucine-rich repeat (NBS-LRR) or other proteins related to disease resistances. Conclusions: The results of this study provide a basis for breeding peanut cultivars with web blotch resistance.

Resistance of peanut to web blotch caused by Phoma arachidicola is related to papillae formation and the hypersensitive response

“…In our previous study, a peanut recombinant inbred line (RIL) population was used to map quantitative trait loci for web blotch resistance on the basis of high-throughput genome-wide sequencing (Liu et al, 2020). In total, eight quantitative trait loci were detected for peanut web blotch resistance in at least two environments, explaining 2.8%-15.1% of the phenotypic variance.…”

Major Plant Diseases Caused by Phoma sensu lato Species and Their Integrated Management Strategies

“…Web blotch is also known as muddy spot or net blotch (Liu et al 2020). This disease is one of the major diseases of peanut.…”

“…The disease has been reported from various parts of Africa, Argentina, China, Russia, Spain, and the USA (Smith and Littrell 1980;McDonald and Beckerman 1985;Pettit et al 1986) and is estimated to cause 10-30% yield loss annually. Severe infections may lead to more than 50% yield loss (Zhang et al 2019;Liu et al 2020).…”

“…Phoma-related species and disease development: although there has been confusion over the generic distinctions between Phoma and Ascochyta in the literature, it seems clear that P. arachidicola Marasas, Pauer & Boerema is the main pathogen of web blotch disease (Hong-hai et al 2013;Zhang et al 2019;Liu et al 2020). The optimum temperature for mycelial growth and spore production is 25 °C.…”

“…Both pseudothecia and chlamydospores are reported to be effective sources of inoculum. Periods of extended thundershowers could result in severe damages (Liu et al 2020). This is mainly due to the reduced light intensity and temperature which favor fungus growth (Zhang et al 2019).…”