Revisions to phavu.Islam_Bett_2020.yml on 20 August 2024

Phaseolus/vulgaris/studies/phavu.Islam_Bett_2020.yml

@@ -11,9 +11,9 @@ curators:
   - Scott Kalberer
 comments:
   - Postharvest seed coat darkening results in decreased consumer preference and lower economic value for the market class of Pinto beans. Rapid and fuller darkening after harvest of dry beans is caused by heavier accumulation of proanthocyanidins (PAs) and PA monomers (epicatechin and catechin) in developing seed coat tissues.
-  - Psd is a recessive allele candidate of the Pigment (P) gene responsible for the slow darkening seed coat in Pinto beans (Phaseolus vulgaris). Evidence provided to show Psd is the sought-for SLOW DARKENING (Sd) gene included genetic complementation, transcript abundance, metabolite analysis, and an inheritance study.
-  - The P gene encodes a basic helix-loop-helix transcription factor with one of its two transcript variants involved in PA biosynthesis. Two mutations in the Psd allele- an additional glutamate residue in the activation domain, and/or an arginine to histidine substitution in the bHLH domain- are likely responsible for reduced protein activity and PA accumulation. Flavonoid biosynthesis leading to proanthocyanidins is regulated by an MBW complex, highly conserved across plant species, consisting of members of the myeloblastosis (MYB), bHLH transcription factor, and WD40 repeat protein (WDR) families.
-  - The P gene in Phaseolus vulgaris is an ortholog of the bHLH transcription factor AtTT8 in Arabidopsis thaliana. Ectopic expression of P from regular darkening bean cultivar CDC Pintium in Arabidopsis tt8 mutants completely restored both the activity of Dihydroflavonol 4-Reductase (DFR) and Anthocyanidin Reductase (ANR) and the wild-type testa phenotype.  However, expression of Psd from slow darkening cultivar 1533-15 only partially restored the mutant phenotype.
+  - Psd is a recessive allele of the Pigment (P) candidate gene responsible for the slow darkening seed coat in Pinto beans (Phaseolus vulgaris). Evidence provided to show that Pigment (allele Psd) is the sought-for SLOW DARKENING (Sd) gene included genetic complementation, transcript abundance, metabolite analysis, and an inheritance study.
+  - The P gene encodes a basic helix-loop-helix transcription factor with one of its two transcript variants (P-1) involved in PA biosynthesis, and the other truncated variant (P-2) having either no or unknown function. Two mutations in the Psd allele- supplemental glutamate residue within the activation domain, and/or arginine to histidine substitution in the bHLH domain- are likely responsible for reduced protein activity and PA accumulation in the slow-darkening (SD) cultivar. Flavonoid biosynthesis leading to proanthocyanidins is regulated by an MBW complex, highly conserved across plant species, consisting of members of the myeloblastosis (MYB), bHLH transcription factor, and WD40 repeat protein (WDR) families.
+  - The P gene in Phaseolus vulgaris is a functional ortholog of the bHLH transcription factor AtTT8 that regulates testa pigment biosynthesis in Arabidopsis thaliana. In genetic complementation tests, ectopic expression of the P-1 allele from regular darkening (RD) bean cultivar CDC Pintium in Arabidopsis tt8 mutants completely restored both the activity of Dihydroflavonol 4-Reductase (AtDFR) and Anthocyanidin Reductase (AtANR) and the wild-type testa phenotype with expected proanthocyanidin levels. Transgenic expression of the Psd-1 allele from slow darkening (SD) cultivar 1533-15 only partially redeemed the mutant phenotype, whereas transfromation with constructs containing P-2 (CDC Pintium) failed to recover the wild-type phenotype. Loss-of-function alleles of the P gene were shown to cause white seed coat color in common bean (McClean, Bett et al., 2018).
   - The gene model Phvul.007G171333 is the P gene and was previously annotated as a type of transcription factor known as TRANSPARENT TESTA 8 (TT8).
 phenotype_synopsis: Pinto bean cultivars carrying the Psd allele of the Pigment gene have seed coats that darken more slowly following harvest.
 traits: