Many root‐knot nematode (RKN) species (Meloidogyne spp.) are polyphagous and cultivated tomato (Solanum lycopersicum) is one of their preferential hosts, leading to significant losses. It is known that the dominant Mi‐1.2 gene in tomato confers resistance to the three most important RKN species—M. incognita, M. javanica, and M. arenaria, and minor species—M. ethiopica, M. hispanica, and M. luci. However, little information is available about resistance of tomatoes carrying this gene to other tomato‐infecting RKN species. In this study, resistance conferred by the Mi‐1.2 gene/locus was evaluated against populations of 15 Meloidogyne species, employing tomato cultivars Santa Clara (homozygous recessive mi‐1.2/mi‐1.2, susceptible) and Debora Plus (heterozygous Mi‐1.2/mi‐1.2, resistant). Debora Plus was susceptible only to M. enterolobii and M. hapla, and was resistant to the other Brazilian populations of M. arenaria, M. ethiopica, M. exigua, M. hispanica, M. incognita, M. inornata, M. izalcoensis M. javanica, M. konaensis, M. luci, M. morocciensis, M. paranaensis, and M. petuniae. Mi‐1.2 is located on tomato chromosome 6 within a cluster of seven homologous genes of the nucleotide‐binding site leucine‐rich repeat (NBS‐LRR) family; further research is required to confirm if this multiple Meloidogyne spp. resistance phenotype is controlled exclusively by Mi‐1.2 or by combined action of other closely linked genes. This evaluation of resistance of the Debora Plus cultivar to several Meloidogyne species suggests that the Mi‐1.2 gene/locus may reduce losses induced by a wide range of Meloidogyne spp. Further studies using additional resistant cultivars and other populations of Meloidogyne spp. are needed to confirm these results.

中文翻译：

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带有 Mi -1.2 基因/位点的“Debora Plus”番茄对十五种根结线虫的抗性

许多根结线虫 (RKN) 物种 (Meloidogyne spp.) 是杂食性的，栽培番茄 (Solanum lycopersicum) 是它们的优先宿主之一，导致重大损失。众所周知，番茄中的显性 Mi-1.2 基因赋予了对三种最重要的 RKN 物种——M. incognita、M. javanica 和 M. arenaria，以及次要物种——M. ethiopica、M. hispanica 和 M. luci。然而，关于携带该基因的番茄对其他番茄感染 RKN 物种的抗性的信息很少。在这项研究中，对 Mi-1.2 基因/位点赋予的抗性针对 15 个根结线虫种群进行了评估，使用番茄栽培品种 Santa Clara（纯合隐性 mi-1.2/mi-1.2，易感）和 Debora Plus（杂合 Mi-1.2/ mi-1.2，抗性）。Debora Plus 仅对 M. enterolobii 和 M. hapla 敏感，并且对 M. arenaria、M. ethiopica、M. exigua、M. hispanica、M. incognita、M. inornata、M. izalcoensis M. javanica、M.konaensis、M. luci、M. morocciensis、M. paranaensis 和 M. petuniae。Mi-1.2 位于番茄 6 号染色体上核苷酸结合位点富含亮氨酸重复序列 (NBS-LRR) 家族的七个同源基因簇内；需要进一步的研究来确认这种多重根结线虫是否。抗性表型仅受 Mi-1.2 或其他紧密连锁基因的联合作用控制。Debora Plus 品种对几种根结线虫的抗性评估表明 Mi-1.2 基因/基因座可以减少由多种根结线虫引起的损失。使用其他抗性品种和其他根结线虫种群进行进一步研究。