Discovery and characterization of a molecular marker for Sclerotinia minor (Jagger) resistance in peanut

Abstract

The production of cultivated peanut, an important agronomic crop throughout the United States and the world, is consistently threatened by various diseases and pests. Sclerotinia minor Jagger (S. minor), the causal agent of Sclerotinia blight, is a major threat to peanut production in the Southwestern US, Virginia and North Carolina. Although information on the variability of morphological traits associated with Sclerotinia blight resistance is plentiful, no molecular markers associated with resistance have been reported. The identiWcation of markers would greatly assist peanut geneticists in selecting genotypes to be used in breeding programs. The main objective of this work was to use simple sequence repeat (SSR) primers previously reported for peanut to identify a molecular marker associated with resistance to S. minor. Out of 16 primer pairs used to examine peanut genomic DNA from 39 diVerent genotypes, one pair produced bands at approximately 145 and 100 bp, consistent with either S. minor resistance or susceptibility, respectively. Cloning and sequencing of these bands revealed the region is well conserved among all genotypes tested with the exception of the length of the SSR region, which varies with disease resistance levels. This is the Wrst report of a molecular marker associated with resistance to Sclerotinia blight in peanut. The identiWcation of this marker and development of a PCR-based screening method will prove to be extremely useful to peanut breeders in screening germplasm collections and segregating populations as well as in pyramiding S. minor resistance with other desirable traits into superior peanut lines. Abbreviations ABLAdvanced breeding line AFLP AmpliWed fragment length polymorphism QTL Quantitative trait loci RAPD Random ampliWed polymorphic DNA RFLP Restriction fragment length polymorphism SCAR Sequence characterized ampliWed region SSR Simple sequence repeat Cultivated peanut (Arachis hypogaea L.) is a selfpollinated allotetraploid (2n = 4x = 40), which is

Reaction of the Core Collection of Peanut Germplasm to Sclerotinia Blight and Pepper Spot1

“…However, the marker was not present in several virginia entries with good resistance. Core entries 103, 128, 208, and 273 that were selected from this study based on their resistance; and the reference cultivars Okrun, Tamrun 96, and Tamspan 90 were tested using polymerase chain reaction in the study by Chenault et al (5). Core entries 103, 128, 208, and 273; and Tamrun 96 each only had the 145 bp band for resistance.…”

“…Bell) and web blotch which became apparent during screenings. Brief excerpts of this research have been previously published (5,11).…”

Marker‐Assisted Selection for Biotic Stress Resistance in Peanut

“…Several resistant cultivars have been developed, but this requires field screening; growth chamber screening can be done (Melouk et al 1992) but does not work with all market types (Wilson 2008). By association analysis of 39 genotypes with 16 SSR markers, 1 SSR marker was found to be associated with resistance (Chenault et al 2009). This marker was found to work in runner, spanish, and valencia market types but not in the virginia market type (Chamberlin et al 2010).…”

Development of trinucleotide (GGC)n SSR markers in peanut (Arachis hypogaea L.)

“…Using SSR markers, genetic diversity of peanut germplasm has been studied in Valencia (Krishna et al 2004), in mini-core collection (Barkley et al 2007), and in Chinese (Tang et al 2007) and Japanese peanut germplasm collections (Naito et al 2008). SSR markers have been identified and characterized for association with resistance traits such as rust and late leaf spot resistance (Mace et al 2006), and resistance against Ralstonia solanacearum and Sclerotinia minor (Chenault et al 2008). Genetic linkage maps with SSR markers have been constructed for diploid AA genome (Moretzsohn et al 2005), BB genome ), tetraploid AABB genome derived from a cross of cultivated with amphidiploids (Foncéka et al 2009), and tetraploid AABB genome in the cultivated peanut (Hong et al 2008, Varshney et al 2009Hong et al 2010).…”