Differences in Resistant Capsicum Annuum Attacked By Different Meloidogyne Species

Pyramiding, alternating or mixing: comparative performances of deployment strategies of nematode resistance genes to promote plant resistance efficiency and durability

“…This validates, under natural field conditions, previous results obtained under controlled conditions [37,38] which also showed that these two genes induce distinct resistance mechanisms, the Me3 gene inducing early cellular necrosis in the root epidermis adjacent to the juveniles whereas Me1 induces a late hypersensitive reaction in the vascular cylinder of infected roots, thus inhibiting the development of egg-laying females [39,40]. The importance of the choice of the R- gene for a better durability of resistance linked to the mechanism of resistance was also pointed out in several pathosystems [7,42,43].…”

“…The superiority of molecules combination over the other strategies appeared to be robust particularly when resistance to each drug in the combination was controlled by independent loci (no cross-resistance), leading to “multiple intragenerational killing” of the pathogens at the individual level. Me1 and Me3 are two distinct R -genes with different modes of action [ 39 , 40 ] and no cross-virulence effects [ 36 ]. Moreover, pyramiding appeared very promising as RKN “traps” plants, reducing up to 90% the infestation rate of the soil, protecting the winter susceptible crops.…”

“…Doux Long des Landes (DLL) is a susceptible cultivar. The two resistant doubled-haploid (DH) lines, DH149 and DH330 produced through in vitro androgenesis were previously described [ 33 ]; they are homozygous for the Me3 and Me1 genes, respectively [ 39 ]. The selection of virulent variants against the Me3 gene was achieved through strong inoculation pressure by avirulent M. incognita isolates [ 36 , 38 ].…”

“…Previous experimental studies showed that two genes (named Me1 and Me3 ) differ in their mode of action, particularly in the spatio-temporal localisation of the hypersensitive reaction (HR) triggered by RKN penetration into the roots [ 37 , 38 ]. Me3 induces early cellular necrosis in the root epidermis adjacent to the juveniles whereas Me1 induces a late hypersensitive reaction in the vascular cylinder of infected roots, thus inhibiting the development of egg-laying females [ 39 , 40 ]. Interestingly, virulent populations were obtained for Me3 , both in natural (i.e., in the field) and artificial (i.e., in the laboratory) conditions, whereas, to date, no evidence showed the emergence of Me1 -virulent populations [ 36 , 37 ], which suggests a possible relationship between the mode of action of these R -genes and their durability.…”

Nuevas herramientas en la lucha contra las virosis del pimiento

“…Siempre a partir de los recursos fitogenéticos disponibles. En el caso del pimiento, se han desarrollado cultivares resistentes a hongos como Phytophtora capsici (Walker y Bosland, 1999) o Colletotrichum capsici (Qing-Lin et al, 2002), a nematodos como Meloidogyne incognita (Hendy et al, 1985) o M. arenaria (Djian-Caporalino et al, 2001) y a bacterias como Xanthomonas campestris (Jones et al, 2002). Sin embargo, actualmente los mejoradores se han centrado en la resistencia a enfermedades virales, al constituir los principales factores limitantes de la producción del pimiento, y porque el desarrollo de variedades resistentes es el método de lucha más eficaz contra estas enfermedades (Tabla 1.2).…”