GWAS of pod morphological and color characters in common bean

Carmen García-Fernández,Ana Campa,Juan Jose Ferreira,Alvaro Soler Garzón,Phil Miklas

doi:10.1186/s12870-021-02967-x

Abstract

BackgroundCommon bean (Phaseolus vulgaris L.) is an important legume species which can be consumed as immature pods and dry seeds after re-hydration and cooking. Many genes and QTL, and epistatic interactions among them, condition pod morphological traits. However, not all them have been mapped or validated nor candidate genes proposed. We sought to investigate the genomic regions conditioning pod morphological and color characters through GWAS.ResultsSingle and multi-locus genome wide association analysis was used to investigate pod traits for a set of 301 bean lines of the Spanish Diversity Panel (SDP). The SDP was genotyped with 32,812 SNPs obtained from Genotyping by Sequencing. The panel was grown in two seasons and phenotypic data were recorded for 17 fresh pods traits grouped in four pod characters: pod length, pod cross-section, pod color, and number of seeds per pod. In all, 23 QTL for pod length, 6 for cross-section, 18 for pod color, 6 for number of seeds per pod and 9 associated to two or more pod characters were detected. Most QTL were located in the telomeric region of chromosomes Pv01, Pv02, Pv04, Pv08, Pv09 and Pv10. Eighteen detected QTL co-localized with 28 previously reported QTL. Twenty-one potential candidate genes involving developmental processes were detected underlying 11 QTL for pod morphological characters, four of them homologous to A. thaliana genes FIS2, SPL10, TTG2 and AML4 affecting silique size. Eight potential candidate genes involved in pigment synthesis, were found underlying five QTL for pod color.ConclusionsGWAS for pod morphological and color characters in the bean Spanish Diversity Panel revealed 62 QTL, 18 co-localized with previously reported QTL, and 16 QTL were underlain by 25 candidate genes. Overall 44 new QTL identified and 18 existing QTL contribute to a better understanding of the complex inheritance of pod size and color traits in common bean and open the opportunity for future validation works.

Highlights

Common bean (Phaseolus vulgaris L.) is an important legume species which can be consumed as immature pods and dry seeds after re-hydration and cooking
Common bean (Phaseolus vulgaris L.) is an important legume species domesticated in two different areas of Latin America representing distinct Mesoamerican and Andean gene pools [1]
The snap bean group includes different market classes such as ‘string snap bean’ referring to types where the pod suture strings must be removed before consumption; ‘yellow wax’ and ‘green bean’, referring to yellow and green pod, respectively; ‘Romano type’ with a very large and flat pod; and ‘blue lake type’ with dark green pods that remain stringless and fibreless [2]

Summary

Introduction

Common bean (Phaseolus vulgaris L.) is an important legume species which can be consumed as immature pods and dry seeds after re-hydration and cooking. Common bean (Phaseolus vulgaris L.) is an important legume species domesticated in two different areas of Latin America representing distinct Mesoamerican and Andean gene pools [1]. Immature pod phenotypic diversity involves variation in length and curvature (straight vs curved), cross section (diameter, flat, round, sieve size), and color (yellow, green, purple) before the seeds start to develop. Immature pods of some bean genotypes are consumed as fresh green beans Green, pole, snap, haricot or French beans) when the pods have reached maximum length while the seed is still forming, in contrast with dry beans that are consumed as mature seeds after rehydration and cooking. Snap bean can be classified according to processing adaptation: frozen, canned, or fresh market

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