Putative genes and pathways for Vascular Streak Dieback resistance in cocoa (Theobroma cacao L.) identified through the characterization of linked markers

Abstract

Vascular Streak Dieback (VSD) caused by the fungus Ceratobasidium theobromae inflicts heavy yield losses in cocoa. Our previous study has identified and validated five ISSR and one SSR markers co-segregating with resistance and shown that they are efficient to select the resistant lines. In this work, to identify the genes and pathways involved in the resistance mechanisms, the ISSR markers for resistance, generated with UBC811, UBC826 and UBC857, were cloned and sequence characterized. The sequences had shown that the resistance loci lie in the chromosomes III and V. Eight disease resistance related proteins, TCM024428 Ankyrin repeat family protein/BTB/POZ domain-containing protein, TCM024455 Calcium-binding EF-hand family protein, TCM011959 Disease resistance protein, TCM012042 Kinase super family protein isoform 2, TCM012044 Basic helix-loop-helix DNA-binding superfamily protein, TCM014828 NBS-LRR resistance protein, TCM014842 Disease resistance family protein/LRR family, and TCM012034 NB-ARC domain-containing disease resistance protein, have been identified along with their partner defence proteins, domains and biological functions. KEGG analysis revealed tcc04075 plant hormone signal transduction pathway and tcc04626 plant-pathogen interaction pathway, having roles in the VSD resistance mechanism. • Molecular markers linked with VSD resistance in cocoa were cloned and sequenced. • Flanking regions of markers had 175 proteins including 8 resistance proteins. • Hormone signal transduction and pathogen interaction pathways were identified. • Protein partners and interaction patterns of resistance proteins were illustrated. • Domains of resistance protein and their roles in defence were predicted.