Evaluation of field pea accessions for root-knot nematode resistance and possible role of NADP dependent malic enzyme gene in host resistance

The present study was undertaken to evaluate resistance of different field pea accessions to RKN, Meloidogyne javanica under microplots and pot culture conditions. Three hundred accessions of field pea were screened initially using sick soil and evaluated after 2 months of sowing using root gall index of 1–5 scale. Based on galling index eleven accessions showing resistant reaction were further screened under controlled condition. All eleven acessions were consistent in their response to RKN infection under pot culture experiment. The partial sequence of NADPdependent malic enzyme (ME) gene was PCR amplified, sequenced and used to screen field pea accessions showing resistant and susceptible reaction against RKN using PCR amplification. PCR screening using ME specific primers showed PCR amplification only in accessions showing resistant reaction. There was no amplification of ME gene from susceptible field pea accessions. The partial sequence of putative NADP dependent Malic enzyme gene from resistant accessions of field pea has been cloned and characterized. The results indicate possible link between ME and resistance against RKN in field pea. Role of malate metabolism in generating resistance reaction against RKN is discussed.