Analysis of Asian rice ( Oryza sativa L.) genotypes reveals a new source of resistance to the root-knot nematode Meloidogyne javanica and the root-lesion nematode Pratylenchus zeae

The sedentary root-knot nematodes, , and the migratory root-lesion nematodes, , cause significant yield losses, particularly in aerobic and upland rice production systems. Recently, the Asian rice accessions LD 24 and Khao Pahk Maw (KPM) were shown to be highly resistant to the root-knot nematode . In this study, we have analyzed the responses and broadness of resistance of these two rice genotypes to another root-knot nematode and a root-lesion nematode to investigate the broadness of resistance. The penetration, as well as post-penetration development and reproduction of nematodes, were compared including known susceptible and resistant genotypes. Our results indicate that the genotype KPM confers strong resistance to and while LD 24 was resistant to and susceptible to . Detailed observations revealed that similar numbers of or nematodes penetrated the resistant and susceptible hosts during early infection stages. However, the development and reproduction of both nematodes were arrested or reduced in resistant genotypes implying that resistance occurs at the post-penetration stage.