Jasmonic acid signaling pathway of Arabidopsis thaliana is important for root-knot nematode invasion

Abstract

We investigated the interaction between infection of the root-knot nematode (RKN), Meloidogyne incognita, and activation of the jasmonic acid (JA) signaling pathway in Arabidopsis thaliana. We monitored the RKN infection response of various Arabidopsis mutants. In addition, we analyzed effects of methyl jasmonate (MeJA) treatment on RKN infection. The number of invading juveniles in the wild type (WT) was significantly reduced by the application of MeJA. RKN infection in the defective salicylic acid mutant (pr1-1) was similar to that of WT. JA over expresser mutants (sa2-1 and sa2-7) had a lower number of juveniles in roots than WT without MeJA treatment, and the repressing effect was not enhanced by MeJA treatment. A negative correlation was found between the activation of the JA related pathway and RKN infection. However, the repressing effect on RKN infection was not changed though JA related genes expressed more than a certain level. RKN infection was also repressed in the JA insensitive mutant (coi1-1). This result might suggest that the COI-1 signaling pathway related to plant reactions such as production of metabolites and gene expression is important for RKN infection into roots. These results also indicated that RKN may require the JA pathway for infection and RKN infection may be suppressed when the JA pathway is activated.