AUTHOR=Jo Jinkwan , Venkatesh Jelli , Han Koeun , Lee Hea-Young , Choi Gyung Ja , Lee Hee Jae , Choi Doil , Kang Byoung-Cheorl 

TITLE=Molecular Mapping of PMR1, a Novel Locus Conferring Resistance to Powdery Mildew in Pepper (Capsicum annuum)

JOURNAL=Frontiers in Plant Science

VOLUME=8

YEAR=2017

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2017.02090

DOI=10.3389/fpls.2017.02090

ISSN=1664-462X

ABSTRACT=<p>Powdery mildew, caused by <italic>Leveillula taurica</italic>, is a major fungal disease affecting greenhouse-grown pepper (<italic>Capsicum annuum</italic>). Powdery mildew resistance has a complex mode of inheritance. In the present study, we investigated a novel powdery mildew resistance locus, <italic>PMR1</italic>, using two mapping populations: 102 ‘VK515' F<sub>2:3</sub> families (derived from a cross between resistant parental line ‘VK515R' and susceptible parental line ‘VK515S') and 80 ‘PM Singang' F<sub>2</sub> plants (derived from the F<sub>1</sub> ‘PM Singang' commercial hybrid). Genetic analysis of the F<sub>2:3</sub> ‘VK515' and F<sub>2</sub> ‘PM Singang' populations revealed a single dominant locus for inheritance of the powdery mildew resistance trait. Genetic mapping showed that the <italic>PMR1</italic> locus is located on syntenic regions of pepper chromosome 4 in a 4-Mb region between markers CZ2_11628 and HRM4.1.6 in ‘VK515R'. Six molecular markers including one SCAR marker and five SNP markers were localized to a region 0 cM from the <italic>PMR1</italic> locus. Two putative nucleotide-binding site leucine-rich repeat (NBS-LRR)-type disease resistance genes were identified in this <italic>PMR1</italic> region. Genotyping-by-sequencing (GBS) and genetic mapping analysis revealed suppressed recombination in the <italic>PMR1</italic> region, perhaps due to alien introgression. In addition, a comparison of species-specific InDel markers as well as GBS-derived SNP markers indicated that <italic>C. baccatum</italic> represents a possible source of such alien introgression of powdery mildew resistance into ‘VK515R'. The molecular markers developed in this study will be especially helpful for marker-assisted selection in pepper breeding programs for powdery mildew resistance.</p>