New genetic sources of resistance in the genus Phaseolus to individual and combined aluminium toxicity and progressive soil drying stresses

Abstract

Bean species and genotypes show wide phenotypic variability in relation to aluminium (Al) resistance and progressive soil drying. The objective of this study was to identify and characterize sources of resistance to Al toxicity and progressive soil drying among six genotypes of common bean (Phaseolus vulgaris), four of runner bean (P. coccineus), and one of tepary bean (P. acutifolius), using hydroponic and soil cylinder screening methods. One experiment on hydroponic screening of Al resistance was carried out using a basal nutrient solution with and without 20 lM Al. Two experiments were carried out using two oxisols in 80 cm long soil cylinders with high Al (HAl) and low Al (LAl) saturation treatments. The three experiments showed an average of 36.9-53.5% inhibition of root growth with HAl compared with LAl treatments. Differences in root development and distribution were observed among genotypes and species. Two accessions of P. coccineus (G35346-2Q, G35464-5Q) and one Andean common bean genotype (ICA Quimbaya) were outstanding in root and shoot growth in the HAl treatments. P. coccineus accession (G35346-3Q) was outstanding under combined stress of Al-toxic acid soil and progressive soil drying. Accessions of P. coccineus may represent unique sources of Al resistance for the improvement of common bean through interspecific crosses.

Root traits and their potential links to plant ideotypes to improve drought resistance in common bean

“…2.2 Root phenotyping using soil cylinder system A greenhouse study was conducted at the main experiment station of the International Center for Tropical Agriculture (CIAT) in Palmira, Colombia, using transparent plastic cylinders (120 cm long, 7.5 cm diameter) filled with a Mollisol from Palmira, Colombia (Polania et al 2009;Butare et al 2011). Soil cylinders were carefully packed with soil: sand mixture (2:1), with a final bulk density of 1.4 g cm -3 .…”

“…However the phenotypic evaluation of root traits under field conditions is labor intensive and expensive. Keeping this in mind, some rapid and cost effective methodology has been used to carry out root phenotypic evaluations, such as small soil cylinders under greenhouse conditions, which allow to evaluate several root traits under different types of abiotic stress (Polania et al 2009;Butare et al 2011Butare et al ,2012. Phenotypic evaluations of root traits in common bean under drought stress have shown the importance of different rooting patterns, including deep rooting which allows access to water from deeper soil layers (Sponchiado et al 1989;White and Castillo 1992;Lynch and Ho 2005;Polania et al 2009Polania et al , 2012Beebe et al 2013Beebe et al , 2014Rao 2014;Burridge et al 2016).…”

“…However, it is noteworthy that some of the key root traits contributing to improved adaptation to soils with low fertility are increased fine root formation and root hairs (Eissenstat 1992;Lynch 2011Lynch , 2013Rao et al 2016). Fine roots and root hairs can explore a large volume of soil and have a low carbon and energy requirement for their function (Eissenstat 1992;Huang and Fry 1998;Polania et al 2009;Butare et al 2011;Lynch 2011Lynch , 2013Rao et al 2016).…”

Functional Genomics of Biotic and Abiotic Stresses in Phaseolus vulgaris

“…They naturally span from the desert highlands of northwest Mexico to the southwest of the USA and thus they are good sources of drought, heat, and cold tolerance [114]. An interesting feature of tepary beans is their root system, which reveals extremely fine roots with rapid penetration in the soil with profuse branching, which enables quick access to limited soil water [115]. expression profiling in mature leaves and root apices across two genotypes.…”

Expression profiling and sequence diversity of novel DREB genes from common bean (Phaseolus vulgaris L.) and their association with drought-related traits

“…An interesting feature of tepary beans is on their root system. It reveals extremely fine roots with rapid penetration in the soil with profuse branching, which enables quick access to limited soil water (BUTARE et al, 2011). Other maps have been developed for specific traits or for evaluating how domestication has shaped genes.…”