Transcriptome Analysis in Musa acuminata during Compatible Interaction with the Root-Knot Nematode Meloidogyne incognita

Endoparasitic root-knot nematodes (RKN) (Meloidogyne spp) cause considerable losses in Banana (Musa sp.), with Meloidogyne incognita a predominant species in edible Cavendish subgroup bananas. This study describes the characterization of the root transcriptome in Musa acuminata genotypes 4297-06 (AA) and Cavendish Grande Naine (CAV) (AAA) during early compatible interactions with M. incognita. Root RNA samples were extracted 3, 7 and 10 days after inoculation with nematode J2 juveniles and paired-end sequenced using lllumina HiSeq 2500 technology. High quality sequences were mapped to the M. acuminata ssp. malaccensis var. Pahang genome sequence using Novoalign/Useq. Differentially expressed genes (DEGs) in infected libraries were identified with the Benjamini-Hochberg algorithm. Representation of DEGs was analyzed using Blast2GO and FUNC. Microscopic analysis of acid fuchsin-stained roots revealed a life cycle of M. incognita completing within 28 days in both genotypes. DEGs were identified in relation to non-inoculated controls, with comparable numbers of genes up- and downregulated in each genotype. GO enrichment analysis revealed terms related to host defense and giant cell development in both genotypes. Notable modulated transcripts related to stress responses included LRR receptor-like serine/threonine-protein kinases, peroxidases, thaumatin-like PR proteins, DREB, ERF, MYB, NAC and WRKY transcription factors. Transcripts related to giant cell development included expansins, endoglucanases, polygalacturonases, pectinmethylesterases, pectate lyases and xyloglucan endotransglucosylase proteins. This analysis of gene expression in M. acuminata during the compatible interaction with RKN provides insights into nematode-induced host expression profiles during infection and giant cell formation that will facilitate downstream development of novel genetic improvement-based control measures for RKN.