Postharvest seed coat darkening in pinto bean (Phaseolus vulgaris) is regulated by Psd, an allele of the basic helix‐loop‐helix transcription factor P
Societal Impact Statement Pinto bean (Phaseolus vulgaris) is one of the leading market classes of dry beans that is most affected by postharvest seed coat darkening. The process of seed darkening poses a challenge for bean producers and vendors as they encounter significant losses in crop value due...
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doaj-b56534c8e3c14cc6844abdeb4dcb87f82020-11-25T03:44:30ZengWileyPlants, People, Planet2572-26112020-11-012666367710.1002/ppp3.10132Postharvest seed coat darkening in pinto bean (Phaseolus vulgaris) is regulated by Psd, an allele of the basic helix‐loop‐helix transcription factor PNishat S. Islam0Kirstin E. Bett1K. Peter Pauls2Frédéric Marsolais3Sangeeta Dhaubhadel4London Research and Development CentreAgriculture and Agri‐Food Canada London ON CanadaDepartment of Plant Sciences University of Saskatchewan Saskatoon SK CanadaDepartment of Plant Agriculture University of Guelph Guelph ON CanadaLondon Research and Development CentreAgriculture and Agri‐Food Canada London ON CanadaLondon Research and Development CentreAgriculture and Agri‐Food Canada London ON CanadaSocietal Impact Statement Pinto bean (Phaseolus vulgaris) is one of the leading market classes of dry beans that is most affected by postharvest seed coat darkening. The process of seed darkening poses a challenge for bean producers and vendors as they encounter significant losses in crop value due to decreased consumer preference for darker beans. Here, we identified a novel allele of the P gene, Psd, responsible for the slow darkening seed coat in pintos, and identified trait‐specific sequence polymorphisms which are utilized for the development of new gene‐specific molecular markers for breeding. These tools can be deployed to help tackle this economically important issue for bean producers. Summary Postharvest seed coat darkening in pinto bean is an undesirable trait that reduces the market value of the stored crop. Regular darkening (RD) pintos darken faster after harvest and accumulate higher level of proanthocyanidins (PAs) compared to slow darkening (SD) cultivars. Although the markers cosegregating with the SD trait have been known for some time, the SLOW DARKENING (Sd) gene identity had not been proven. Here, we identified Psd as a candidate for controlling the trait. Genetic complementation, transcript abundance, metabolite analysis, and inheritance study confirmed that Psd is the Sd gene. Psd is another allele of the P (Pigment) gene, whose loss‐of‐function alleles result in a white seed coat. Psd encodes a bHLH transcription factor with two transcript variants but only one is involved in PA biosynthesis. An additional glutamate residue in the activation domain, and/or an arginine to histidine substitution in the bHLH domain of the Psd‐1 transcript in the SD cultivar is likely responsible for the reduced activity of this allele compared to the allele in a RD cultivar, leading to reduced PA accumulation. Overall, we demonstrate that a novel allele of P, Psd, is responsible for the SD phenotype, and describe the development of new, gene‐specific, markers that could be utilized in breeding to resolve an economically important issue for bean producers.https://doi.org/10.1002/ppp3.10132Basic helix‐loop‐helix transcription factorgene‐specific markergenetic complementationpinto beanpostharvest seed coat darkeningproanthocyanidins |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Nishat S. Islam Kirstin E. Bett K. Peter Pauls Frédéric Marsolais Sangeeta Dhaubhadel |
spellingShingle |
Nishat S. Islam Kirstin E. Bett K. Peter Pauls Frédéric Marsolais Sangeeta Dhaubhadel Postharvest seed coat darkening in pinto bean (Phaseolus vulgaris) is regulated by Psd, an allele of the basic helix‐loop‐helix transcription factor P Plants, People, Planet Basic helix‐loop‐helix transcription factor gene‐specific marker genetic complementation pinto bean postharvest seed coat darkening proanthocyanidins |
author_facet |
Nishat S. Islam Kirstin E. Bett K. Peter Pauls Frédéric Marsolais Sangeeta Dhaubhadel |
author_sort |
Nishat S. Islam |
title |
Postharvest seed coat darkening in pinto bean (Phaseolus vulgaris) is regulated by Psd, an allele of the basic helix‐loop‐helix transcription factor P |
title_short |
Postharvest seed coat darkening in pinto bean (Phaseolus vulgaris) is regulated by Psd, an allele of the basic helix‐loop‐helix transcription factor P |
title_full |
Postharvest seed coat darkening in pinto bean (Phaseolus vulgaris) is regulated by Psd, an allele of the basic helix‐loop‐helix transcription factor P |
title_fullStr |
Postharvest seed coat darkening in pinto bean (Phaseolus vulgaris) is regulated by Psd, an allele of the basic helix‐loop‐helix transcription factor P |
title_full_unstemmed |
Postharvest seed coat darkening in pinto bean (Phaseolus vulgaris) is regulated by Psd, an allele of the basic helix‐loop‐helix transcription factor P |
title_sort |
postharvest seed coat darkening in pinto bean (phaseolus vulgaris) is regulated by psd, an allele of the basic helix‐loop‐helix transcription factor p |
publisher |
Wiley |
series |
Plants, People, Planet |
issn |
2572-2611 |
publishDate |
2020-11-01 |
description |
Societal Impact Statement Pinto bean (Phaseolus vulgaris) is one of the leading market classes of dry beans that is most affected by postharvest seed coat darkening. The process of seed darkening poses a challenge for bean producers and vendors as they encounter significant losses in crop value due to decreased consumer preference for darker beans. Here, we identified a novel allele of the P gene, Psd, responsible for the slow darkening seed coat in pintos, and identified trait‐specific sequence polymorphisms which are utilized for the development of new gene‐specific molecular markers for breeding. These tools can be deployed to help tackle this economically important issue for bean producers. Summary Postharvest seed coat darkening in pinto bean is an undesirable trait that reduces the market value of the stored crop. Regular darkening (RD) pintos darken faster after harvest and accumulate higher level of proanthocyanidins (PAs) compared to slow darkening (SD) cultivars. Although the markers cosegregating with the SD trait have been known for some time, the SLOW DARKENING (Sd) gene identity had not been proven. Here, we identified Psd as a candidate for controlling the trait. Genetic complementation, transcript abundance, metabolite analysis, and inheritance study confirmed that Psd is the Sd gene. Psd is another allele of the P (Pigment) gene, whose loss‐of‐function alleles result in a white seed coat. Psd encodes a bHLH transcription factor with two transcript variants but only one is involved in PA biosynthesis. An additional glutamate residue in the activation domain, and/or an arginine to histidine substitution in the bHLH domain of the Psd‐1 transcript in the SD cultivar is likely responsible for the reduced activity of this allele compared to the allele in a RD cultivar, leading to reduced PA accumulation. Overall, we demonstrate that a novel allele of P, Psd, is responsible for the SD phenotype, and describe the development of new, gene‐specific, markers that could be utilized in breeding to resolve an economically important issue for bean producers. |
topic |
Basic helix‐loop‐helix transcription factor gene‐specific marker genetic complementation pinto bean postharvest seed coat darkening proanthocyanidins |
url |
https://doi.org/10.1002/ppp3.10132 |
work_keys_str_mv |
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