Linkage and mapping of resistance genes toXanthomonas axonopodispv.passifloraein yellow passion fruit

Abstract

The cultivated passion fruit (Passiflora edulis f. flavicarpa) is a cross-pollinated species native to South America. In the current study, a segregating F1 population derived from a single cross between the clones IAPAR-06 and IAPAR-123 was used to construct AFLP-based linkage maps and to map resistance genes to bacterial spot caused by Xanthomonas axonopodis pv. passiflorae. Linkage analysis was performed by the 2-way pseudo-testcross mapping method using markers that segregated in a 1:1 ratio. The IAPAR-06 linkage map was constructed using 115 markers, 112 of which were allocated to 9 linkage groups (LG) covering 790.2 cM. The map of IAPAR-123 was constructed using 140 markers, 138 of which were allocated to 9 LG covering 488.9 cM. In both maps, clusters of markers were detected, indicating that the AFLP markers were not distributed at random. Bacterial resistance was assessed by measuring the diseased leaf area after wound-inoculating the leaves of F1 plants. Quantitative resistance loci (QRLs) mapping was carried out by composite interval mapping and 1 QRL was detected, which explained 15.8% of the total phenotypic variation. The possibility of considering these data for marker-assisted selection in passion fruit breeding programs is discussed.

Characterization and selection of passion fruit (yellow and purple) accessions based on molecular markers and disease reactions for use in breeding programs

“…passiflorae yellow passion fruit, have occurred since 2002 (Lopes et al 2006;Carneiro et al 2002). In this context, with the addition of a new set of microsatellite markers, the first integrated map of passion fruit was published for P. edulis , providing the ability to use this information for identifying quantitative trait loci (QTLs).…”

Variabilidade genética de Xanthomonas axonopodis pv. passiflorae

“…Embora o conhecimento da resistência genética de Passiflora à bacteriose do maracujazeiro ainda seja incipiente, resultados obtidos têm indicado variabilidade do caráter dentro da espécie e herança quantitativa (13,17,19). Para que a resistência genética seja utilizada de maneira eficiente no desenvolvimento de variedades que apresentem resistência duradoura e de amplo espectro é necessário tanto o conhecimento das fontes de resistência na espécie hospedeira como da variabilidade da agressividade na população do patógeno.…”

Diversidade genética de isolados de xanthomonas axonopodis pv. passiflorae com base em marcadores rep-PCR e AFLP e construção de primers específicos para diagnose

“…A resistência à bacteriose é controlada por oligogenes, porém não há variedades selecionadas para expressar os alelos favoráveis detectados na população segregante estudada por Lopes et al (2006).…”

“…Baseado no protocolo utilizado por Lopes et al (2006), modificado de Vos et al (1995), na etapa de hidrólise enzimática foi feita uma dupla digestão, ou seja, uma reação com as duas enzimas de restrição simultaneamente. Na reação, foram usados 250 ng de DNA, 1X de tampão …”