Common bean response to the root knot nematode Meloidogyne incognita: QLT mapping, transcriptional profile and functional studies of candidate resistance genes

Abstract

Nematode attacks are considered among the major phytosanitary issues in common bean (Phaseolus vulgaris) crops. The root-knot nematodes of the genus Meloidogyne are possibly the most widely distributed pest, particularly M. incognita, one of the most damaging crop pathogens. The practices for nematode control usually involve infeasible field management. The chemical control is inefficient, expensive and raises environmental problems, demanding resistant cultivar development. Although the availability of new genetic and molecular approaches (SNPs for instance), a few has been done to understanding the mechanisms underlying the common bean response to root-knot nematodes. In this scenario, this project aims to move on with joint efforts of our part (IAC Common Bean Breeding Program and the ESALQ' Genetics Department), specially related to the identification of candidate genes and genomic regions involved in the common bean response to root-knot nematodes. This proposal comprises five subprojects, including: QTL mapping associated with resistance in the host; comparative transcriptional profiling of two contrasting genotypes; functional studies of candidate genes, via Agrobacterium transformation and gene editing; analysis of the interaction between the common bean - Fusarium oxysporum - M. incognita; and finally, the evaluation of pre-commercial breeding lines. Thus, the expected results may contribute to: understand the genetic architecture of the host resistance to the root-knot nematode, identify SNPs which allow the screening of resistant genotypes and marker assisted selection, reducing the necessity of the challenging phenotypic evaluation; move forward for unveiling the molecular mechanisms underlying the complex M. incognita - P. vulgaris interaction; identify genes related to the common bean response to root-knot nematodes, and develop and characterize cultivars in relation to the resistance. (AU)