AUTHOR=Changkwian Amornrat , Venkatesh Jelli , Lee Joung-Ho , Han Ji-Woong , Kwon Jin-Kyung , Siddique Muhammad Irfan , Solomon Abate Mekonnen , Choi Gyung-Ja , Kim Eunji , Seo Yunhee , Kim Young-Ho , Kang Byoung-Cheorl 

TITLE=Physical Localization of the Root-Knot Nematode (Meloidogyne incognita) Resistance Locus Me7 in Pepper (Capsicum annuum)

JOURNAL=Frontiers in Plant Science

VOLUME=10

YEAR=2019

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2019.00886

DOI=10.3389/fpls.2019.00886

ISSN=1664-462X

ABSTRACT=<p>The root-knot nematode (RKN) <italic>Meloidogyne incognita</italic> severely reduces yields of pepper (<italic>Capsicum annuum</italic>) worldwide. A single dominant locus, <italic>Me7</italic>, conferring RKN resistance was previously mapped on the long arm of pepper chromosome P9. In the present study, the <italic>Me7</italic> locus was fine mapped using an F<sub>2</sub> population of 714 plants derived from a cross between the RKN-susceptible parent <italic>C. annuum</italic> ECW30R and the RKN-resistant parent <italic>C. annuum</italic> CM334. CM334 exhibits suppressed RKN juvenile movement, suppressed feeding site enlargement and significant reduction in gall formation compared with ECW30R. RKN resistance screening in the F<sub>2</sub> population identified 558 resistant and 156 susceptible plants, which fit a 3:1 ratio confirming that this RKN resistance was controlled by a single dominant gene. Using the <italic>C. annuum</italic> CM334 reference genome and BAC library sequencing, fine mapping of <italic>Me7</italic> markers was performed. The <italic>Me7</italic> locus was delimited between two markers G21U3 and G43U3 covering a physical interval of approximately 394.7 kb on the CM334 chromosome P9. Nine markers co-segregated with the <italic>Me7</italic> gene. A cluster of 25 putative nucleotide-binding site and leucine-rich repeat (NBS-LRR)-type disease resistance genes were predicted in the delimited <italic>Me7</italic> region. We propose that RKN resistance in CM334 is mediated by one or more of these NBS-LRR class <italic>R</italic> genes. The <italic>Me7</italic>-linked markers identified here will facilitate marker-assisted selection (MAS) for RKN resistance in pepper breeding programs, as well as functional analysis of <italic>Me7</italic> candidate genes in <italic>C. annuum</italic>.</p>