Members of the WRKY gene family are upregulated in Canary palms attacked by Red Palm Weevil

The Red Palm Weevil (RPW), Rhynchophorus ferrugineus, is one of the major pests affecting several palm species all around the world. The aim of this work was to identify palm genes that are responsive to RPW infestations as a valuable diagnostic tool to detect the insect attack. We have analysed a total of 15 genes that were divided in two subsets: (1) 7 genes previously linked with RPW attacks, but not involved in biotic stress responses, and (2) 8 genes encoding members of the WRKY family, a class of transcription factors well-known to be linked with both abiotic and biotic stress responses. The analysis was conducted on 4-year-old Canary palms comparing uninfested plants and infested plants at 30 and 45 days after RPW oviposition. Principal component analysis of gene expression data showed that the overall analysis of WRKYs partially distinguished the three groups of plants. No separation of the three groups was observed when PCA was conducted using genes that were not linked with biotic stress responses. Among the 8 analysed WRKYs, 4 genes (WRKY2, WRKY28, WRKY14, WRKY51) were significantly induced by RPW attacks at 45 days after the beginning of the infestation. These four WRKYs could be further investigated to confirm if they may be used to help diagnosis of RPW infestations in palm.