Angoisse et complexe de castration

Durability of plant major resistance genes to pathogens depends on the genetic background, experimental evidence and consequences for breeding strategies

“…Whatever the number of QTL, the higher virulence of isolate 53 in plants possessing the major gene and/ or resistance QTL, compared with the PVY clone with the double mutation in the VPg, clearly indicates that additional mutation(s) in other genome regions of this isolate confer a higher virulence towards the major gene, the resistance QTL from the genetic background and their combination. The direct observation of adaptation of virus populations to the resistant host revealed the progressive changes that lead to the gain of virulence, as was observed a posteriori by Le Guen et al (2007) [Correction added on 14 May 2009, after first online publication: the citation year for 'Le Guen et al' was changed from '2006Guen et al' was changed from ' ' to '2007 who isolated Microcyclus ulei strains that bypassed enlarged sets of QTL after large deployment of resistant rubber trees. Together, these results show that the gain of virulence towards the polygenic resistance in field conditions requires multiple mutations, and argues in favour of our first hypothesis that at least one additional mutation within the VPg but also additional mutation(s) in other genome parts were required for virulence towards polygenic resistance in fields.…”

“…Highly durable polygenic resistance was observed in several pathosystems where monogenic resistance failed (Turkensteen, 1993;Chen et al, 2003;Schurnbusch et al, 2004). However, a few analyses showed that pathogen populations may adapt to polygenic resistances, bypassing all or part of the resistance quantitative trait loci (QTL) (Le Guen et al, 2007) [Correction added on 14 May 2009, after first online publication: the citation year for 'Le Guen et al' was changed from '2006Guen et al' was changed from ' ' to '2007. In this case, resistance bypassing was observed a posteriori (i.e.…”