Spectrum of resistance to root-knot nematodes and inheritance of heat-stable resistance in in pepper (Capsicum annuum L.)

Abstract

Capsicum annuum L. has resistance to root-knot nematodes (RKN) (Meloidogyne spp.), severe polyphagous pests that occur world-wide. Several single dominant genes confer this resistance. Some are highly specific, whereas others are effective against a wide range of species. The spectrum of resistance to eight clonal RKN populations of the major Meloidogyne species, M. arenaria (2 populations), M. incognita (2 populations), M. javanica (1 population), and M. hapla (3 populations) was studied using eight lines of Capsicum annuum. Host susceptibility was determined by counting the egg masses (EM) on the roots. Plants were classified into resistant (R; EM ≤ 5) or susceptible (H; EM >5) classes. The french cultivar Doux Long des Landes was susceptible to all nematodes tested. The other seven pepper lines were highly resistant to M. arenaria, M. javanica and one population of M. hapla. Variability in resistance was observed for the other two populations of M. hapla. Only lines PM687, PM217, Criollo de Morelos 334 and Yolo NR were resistant to M. incognita. To investigate the genetic basis of resistance in the highly resistant line PM687, the resistance of two progenies was tested with the two populations of M. incognita: 118 doubled-haploid (DH) lines obtained by androgenesis from F(1) hybrids of the cross between PM687 and the susceptible cultivar Yolo Wonder, and 163 F(2) progenies. For both nematodes populations, the segregation patterns 69 R / 49 S for DH lines and 163 R / 45 S for F(2) progenies were obtained at 22°C and at high temperatures (32°C and 42°C). The presence of a single dominant gene that totally prevented multiplication of M. incognita was thus confirmed and its stability at high temperature was demonstrated. This study confirmed the value of C. annuum as a source of complete spectrum resistance to the major RKN.

Physical mapping of NBS-coding resistance genes to the Me-gene cluster on chromosome P9 reveals markers tightly linked to the N gene for root-knot nematode resistance in pepper

“…These genes confer resistance based on gene-for-gene interaction mechanisms (Fazari et al 2012). Four of the ten genes (Me1, Me3, Me7 and N) confer resistance to a wide range of RKN species (Djian-Caporalino et al 1999). Thus, these genes are important resources for the development of resistant pepper cultivars.…”

Development of a SNP-based CAPS assay for the Me1 gene conferring resistance to root knot nematode in pepper

“…Root knot nematode resistance in pepper was first described by Hare (1956) and attributed to the dominant gene N. Subsequently several other dominant resistance (R) genes, the Me and Mech genes, were identified and characterized, some conferring species-specific immunity and others imparting resistance to a wide range of root knot nematode species (Hendy et al 1983(Hendy et al , 1985Djian-Caporalino et al 1999). Using inbred lines derived from three C. annuum accessions (PI322719, PI201234, CM334) of separate genetic and geographical origin, DjianCaporalino et al (2007) fine-mapped six of the Me genes (Me1, Me3, Me4, Me7, Mech1, Mech2) to a 28 cM region of pepper chromosome 9.…”

Resistance of pepper lines against Meloidogyne incognita

“…PM 217, PM 687 ve Carolina Cayenne M. incognita'ya karşı dayanıklılık göstermiştir. Birçok çalışmada da PM 217 ve PM 687 hatlarının M. incognita'ya karşı dayanıklı olduğu belirtilmiştir (Bleve-Zacheo et al, 1998;Djian-Caporalino et al, 1999;2001;2007). Djian-Caporalino et al (2001) PM 217, PM 687, CM334 ve Yolo Wonder biber hatlarının kök ur nematodlarına dayanıklı olduğu bildirmiştir.…”

“…Bu dayanıklılığın 32 0 C de bile etkili olduğu ve kırılmadığı saptanmıştır (Thies & Fery, 2002). Djian-Caporalino et al (1999, 2001, 2007 (Hare, 1957;Bleve-Zacheo et al, 1998;Djian-Caporalino et al, 2001;2007;Wang & Bosland, 2006;Wang et al, 2009). …”