Claverie M, Bosselut N, Lecouls A C, Voisin R, Lafargue B, Poizat C, Kleinhentz M, Laigret F, Dirlewanger E, Esmenjaud D
Unité "Interactions Plantes-Microorganismes et Santé Végétale", Equipe de Nématologie, Institut National de la Recherche Agronomique, B.P. 2078, 06606 Antibes Cedex, France.
Theor Appl Genet. 2004 Feb;108(4):765-73. doi: 10.1007/s00122-003-1463-1. Epub 2003 Oct 16.
Prunus species express different ranges and levels of resistance to the root-knot nematodes (RKN) Meloidogyne spp. In Myrobalan plum ( Prunus cerasifera), the dominant Ma gene confers a high-level and wide-spectrum resistance to the predominant RKN, Meloidogyne arenaria, Meloidogyne incognita, Meloidogyne javanica and the isolate Meloidogyne sp. Florida which overcomes the resistance of the Amygdalus sources. In Japanese plum ( Prunus salicina), a similar wide-spectrum dominant resistance gene, termed R(jap), has been hypothesized from an intraspecific segregating cross. In peach, two crosses segregating for resistance to both M. incognita and M. arenaria were used to identify single genes that each control both RKN species in the Shalil ( R(Mia557)) and Nemared ( R(MiaNem)) sources. Localisation of these genes was made possible using the RFLP and SSR- saturated reference Prunus map TxE, combined with a BSA approach applied to some of the genes. The Ma1 allele carried by the Myrobalan plum accession P.2175 was localised on the linkage group 7 at an approximate distance of 2 cM from the SSR marker pchgms6. In the Japanese plum accession J.222, the gene R(jap) was mapped at the same position in co-segregation with the SSR markers pchgms6 and CPPCT022. The peach genes R(Mia557) and R(MiaNem), carried by two a priori unrelated resistance sources, were co-localized in a subtelomeric position on linkage group 2. This location was different from the more centromeric position previously proposed by Lu et al. (1999) for the resistance gene Mij to M. incognita and M. javanica in Nemared, near the SSR pchgms1 and the STS EAA/MCAT10. By contrast, R(Mia557) and R(MiaNem) were flanked by STS markers obtained by Yamamoto and Hayashi (2002) for the resistance gene Mia to M. incognita in the Japanese peach source Juseitou. Concordant results for the three independent sources, Shalil, Nemared and Juseitou, suggest that these peach RKN sources share at least one major gene resistance to M. incognita located in this subtelomeric position. We showed that plum and peach genes are independent and, thus, can be pyramided into interspecific hybrid rootstocks based on the plum and peach species.
李属物种对根结线虫（RKN）南方根结线虫属（Meloidogyne spp.）表现出不同程度和水平的抗性。在樱桃李（Prunus cerasifera）中，显性Ma基因对主要的根结线虫南方根结线虫（Meloidogyne arenaria）、爪哇根结线虫（Meloidogyne javanica）和弗罗里达根结线虫分离物（Meloidogyne sp. Florida）具有高水平和广谱抗性，后者克服了扁桃属资源的抗性。在日本李（Prunus salicina）中，从种内分离杂交中推测出一个类似的广谱显性抗性基因，称为R(jap)。在桃中，利用两个对南方根结线虫和花生根结线虫均表现抗性分离的杂交组合，鉴定出分别在沙利尔（R(Mia557)）和内马雷德（R(MiaNem)）资源中控制这两种根结线虫的单个基因。利用RFLP和SSR饱和的李属参考图谱TxE，并结合对部分基因应用的BSA方法，实现了这些基因的定位。樱桃李种质P.2175携带的Ma1等位基因定位在第7连锁群上，距离SSR标记pchgms6约2 cM。在日本李种质J.222中，基因R(jap)与SSR标记pchgms6和CPPCT022共分离，定位在相同位置。桃基因R(Mia557)和R(MiaNem)分别来自两个先验无关的抗性资源，共定位在第2连锁群的亚端粒位置。该位置与Lu等人（1999年）先前提出的内马雷德中对南方根结线虫和爪哇根结线虫的抗性基因Mij的着丝粒位置不同，后者靠近SSR pchgms1和STS EAA/MCAT10。相比之下，R(Mia557)和R(MiaNem)两侧是Yamamoto和Hayashi（2002年）为日本桃种质十胜头中对南方根结线虫的抗性基因Mia获得的STS标记。沙利尔、内马雷德和十胜头这三个独立资源的一致结果表明，这些桃根结线虫资源在该亚端粒位置共享至少一个对南方根结线虫的主要抗性基因。我们表明，李属和桃属的基因是独立的，因此，可以基于李属和桃属物种将它们聚合到种间杂交砧木中。
