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Article|01 Jan 2021|OPEN
Common bean SNP alleles and candidate genes affecting photosynthesis under contrasting water regimes
Susana Trindade Leitão1, Maria Catarina Bicho1,2, Priscila Pereira1, Maria João Paulo3, Marcos Malosetti3,4, Susana de Sousa Araújo1,5, Fred van Eeuwijk3 & Maria Carlota Vaz Patto1
1Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
2Present address: Instituto Superior de Agronomia, Universidade de Lisboa, Lisboa, Portugal
3Wageningen University& Research, Wageningen, The Netherlands
4Present address: Nunhems Vegetable Seeds, Nunhem, The Netherlands
5Present address: Association BLC3—Technology and Innovation Campus, Centre Bio R&D Unit, Oliveira do Hospital, Lisboa, Portugal

Horticulture Research 8,
Article number: 4 (2021)
doi: 10.1038/hortres.2021.4
Views: 476

Received: 05 Aug 2020
Revised: 22 Oct 2020
Accepted: 31 Oct 2020
Published online: 01 Jan 2021


Water deficit is a major worldwide constraint to common bean (Phaseolus vulgaris L.) production, being photosynthesis one of the most affected physiological processes. To gain insights into the genetic basis of the photosynthetic response of common bean under water-limited conditions, a collection of 158 Portuguese accessions was grown under both well-watered and water-deficit regimes. Leaf gas-exchange parameters were measured and photosynthetic pigments quantified. The same collection was genotyped using SNP arrays, and SNP-trait associations tested considering a linear mixed model accounting for the genetic relatedness among accessions. A total of 133 SNP-trait associations were identified for net CO2 assimilation rate, transpiration rate, stomatal conductance, and chlorophylls a and b, carotenes, and xanthophyll contents. Ninety of these associations were detected under water-deficit and 43 under well-watered conditions, with only two associations common to both treatments. Identified candidate genes revealed that stomatal regulation, protein translocation across membranes, redox mechanisms, hormone, and osmotic stress signaling were the most relevant processes involved in common bean response to water-limited conditions. These candidates are now preferential targets for common bean water-deficit-tolerance breeding. Additionally, new sources of water-deficit tolerance of Andean, Mesoamerican, and admixed origin were detected as accessions valuable for breeding, and not yet explored.