Understanding the genetic background of drought tolerance in common bean (Phaseolus vulgaris L.) can aid its resilience improvement. However, drought response studies in large seeded genotypes of Andean origin are insufficient. Here, a novel Andean intra-gene pool genetic linkage map was created for quantitative trait locus (QTL) mapping of drought-responsive traits in a recombinant inbred line population from a cross of two cultivars differing in their response to drought. Single environment and QTL × environment analysis revealed 49 QTLs for physiology, phenology, and yield-associated traits under control and/or drought conditions. Notable QTLs for days to flowering (Df1.1 and Df 1.2) were co-localized with a putative QTL for days to pods (Dp1.1) on linkage group 1, suggesting pleiotropy for genes controlling them. QTLs with stable effects for number of seeds per pod (Sp2.1) in both seasons and putative water potential QTLs (Wp1.1, Wp5.1) were detected. Detected QTLs were validated by projection on common bean consensus linkage map. Drought response-associated QTLs identified in the novel Andean recombinant inbred line (RIL) population confirmed the potential of Andean germplasm in improving drought tolerance in common bean. Yield-associated QTLs Syp1.1, Syp1.2, and Sp2.1 in particular could be useful for marker-assisted selection for higher yield of Andean common beans.

Drought is one of the major threats to common bean (Phaseolus vulgaris L.), affecting its growth and productivity and, thus, contributing to considerable losses in yield in many regions worldwide. The development of varieties tolerant of drought stress has, therefore, become one of the primary goals in many common bean breeding programs. Plants have developed various mechanisms of their adaptation, to a greater or lesser extent, to drought. These are expressed, on the molecular level, by changes of gene expression and of protein content, together with responses at physiological and morphological levels. The response of common bean to drought is still not sufficiently well characterized due to its genetic complexity and its diverse, often ambiguous, phenotypic effects. Understanding these mechanisms is thus of fundamental importance for developing varieties that are better adapted to such stress conditions. In this chapter, we present research that provides an insight into the morpho-physiological adaptation and its underlying molecular changes in common bean plants exposed to drought. We include our contribution to establishing the basis for breeding of common bean with greater tolerance to this abiotic stress that uses molecular markers and identification of quantitative trait loci (QTLs).

Virus‐induced systemic necrosis accounts for great yield losses in potato ( Solanum tuberosum ) cultivars susceptible to the necrotic strain of potato virus Y ( PVY ^NTN ). To extend understanding of systemic necrosis, the tissue of healthy and PVY ^NTN ‐infected potato tubers (necrotic and non‐necrotic) during storage was profiled for host gene expression using microarrays while virus concentration was determined using RT ‐ qPCR . Comparison of non‐necrotic tissue types revealed minor transcriptional differences, while tuber necrosis was characterized by high virus concentration and pronounced expression of defence response‐associated genes. Creation of programmed cell death‐associated gene ontology enabled assessment of expression and regulation of relevant differentially expressed genes implicated in the execution of plant programmed cell death. Vacuolar cell death and unfolded protein response to viral infection were implicated in the necrotic tuber tissue by transcriptional induction of genes possessing caspase‐like activity and genes coding for endoplasmic reticulum chaperones and folding proteins. A meta‐analysis, including all relevant publicly available gene expression datasets differing in genotype, pathogen interaction type and potato organ, revealed common defence responses associated with cell wall fortification, oxidative and biotic stress. The response in necrotic tissues of susceptible tubers resembled the hypersensitive response of resistant primary infected plants, but with hormonal signalling as an important differentiating factor. This study will be useful for in‐depth analysis of programmed cell death regulation in plants by providing gene ontology. It specifically addresses the issue of systemic necrosis formation in PVY ^NTN ‐infected potato tubers during storage.