CsMYB36 is involved in the formation of yellow green peel in cucumber (Cucumis sativus L.)

Zhou

et al. 2021

IJMS

Yellow peel will adversely affect the appearance quality of cucumber fruit, but the metabolites and the molecular mechanism of pigment accumulation in cucumber peel remain unclear. Flavonoid metabolome and transcriptome analyses were carried out on the young peel and old peel of the color mutant L19 and the near-isogenic line L14. The results showed that there were 165 differential flavonoid metabolites in the old peel between L14 and L19. The total content of representative flavonoid metabolites in the old peel of L14 was 95 times that of L19, and 35 times that of young peel of L14, respectively. This might explain the difference of pigment accumulation in yellow peel. Furthermore, transcriptome analysis showed that there were 3396 and 1115 differentially expressed genes in the yellow color difference group (Young L14 vs. Old L14 and Old L14 vs. Old L19), respectively. These differentially expressed genes were significantly enriched in the MAPK signaling pathway–plant, plant–pathogen interaction, flavonoid biosynthesis and cutin, suberine and wax biosynthesis pathways. By analyzing the correlation between differential metabolites and differentially expressed genes, six candidate genes related to the synthesis of glycitein, kaempferol and homoeriodictyol are potentially important. In addition, four key transcription factors that belong to R2R3-MYB, bHLH51 and WRKY23 might be the major drivers of transcriptional changes in the peel between L14 and L19. Then, the expression patterns of these important genes were confirmed by qRT-PCR. These results suggested that the biosynthesis pathway of homoeriodictyol was a novel way to affect the yellowing of cucumber peel. Together, the results of this study provide a research basis for the biosynthesis and regulation of flavonoids in cucumber peel and form a significant step towards identifying the molecular mechanism of cucumber peel yellowing.

Section: Introductionmentioning

confidence: 99%

“…The peel color is a quantitative character, and its gene expression is affected by the environment [ 8 ]. Hutchins first classified the peel color of mature cucumber fruit into four categories: red, orange, yellow and cream, and proposed it was controlled by two genes R and C [ 9 ].…”

Section: Introductionmentioning

confidence: 99%

Integrated Metabolome and Transcriptome Analysis Unveils Novel Pathway Involved in the Formation of Yellow Peel in Cucumber

Zhou

et al. 2021

IJMS

“…KASP is a flexible, cost-effective tool to distinguish alleles between parents and progeny in segregating populations. KASP has been used to verify causal genes in cloned regions of cucumber (Cucumis sativus L.) 31,36 . Our genotyping analysis showed that SNP 25,986,068 of BraA03g050600.3C cosegregated with the phenotype of the F 2 segregation population.…”

Section: Discussionmentioning

confidence: 99%

“…Sakuraba et al 30 proposed that SGRs recruit CCEs based on their ability to bind light-harvesting complex II (LHCII) and their interactions with CCEs. Shimoda et al (2016) showed that SGRs encode mg-dechelatases 31 . STAY-GREEN is a functional mg-dechelatase that extracts magnesium from free chlorophyll and chlorophyll complexes and therefore participates in chlorophyll and photosystem degradation.…”

Section: Introductionmentioning

confidence: 99%

Defect in Brnym1, a magnesium-dechelatase protein, causes a stay-green phenotype in an EMS-mutagenized Chinese cabbage (Brassica campestris L. ssp. pekinensis) line

et al. 2020

Leaf color is an important target trait in Chinese cabbage breeding programs. Leaf yellowing may reduce crop commercial and nutritional values. Some plants with the "stay-green" trait maintain leaf greenness during senescence and even after death. Stay-green Chinese cabbage may be a focal point of future breeding projects because it could improve crop quality and yield and prolong shelf life. A new stay-green mutant, non-yellowing mutant 1 (nym1), was identified in Chinese cabbage derived from an ethyl methane sulfonate (EMS)-mutagenized population. The mutant had stay-green characteristics and a higher chlorophyll content than the wild-type during leaf senescence. The staygreen trait in the mutant Chinese cabbage was controlled by the recessive gene Brnym1. MutMap and KASP analyses showed that Brnym1 (BraA03g050600.3C) encodes an mg-dechelatase (SGR protein), which might be the causal gene of the mutation in Chinese cabbage. A nonsynonymous single nucleotide base substitution (G to A) in the third exon of Brnym1 caused an amino acid substitution from L to F in the highly conserved domain of the magnesiumdechelatase. Ectopic overexpression showed that the BrNYM1 gene of wild-type Chinese cabbage complemented the SGR-defective stay-green mutant nye1-1 of Arabidopsis. The magnesium-dechelatase activity in the nym1 mutant was significantly downregulated compared to that in the wild type. Brnym1 was relatively upregulated in the mutant during late senescence, and BrNYM1 was localized to the chloroplasts. These results indicate that Brnym1 (BraA03g050600.3C) is the causal gene of the stay-green mutation and could be of particular significance in the genetic improvement of Chinese cabbage.

“…In cucumber, two genes responsible for fruit color were identified by map-based cloning. A single-nucleotide insertion in APRR2 was responsible for a white immature fruit color (Liu H. et al, 2016), while a mutation in MYB36 resulted in the formation of a yellow-green peel mutant (Hao et al, 2018). A 4-bp insertion in a putative R3 MYB repressor, SIMYBATV , led to anthocyanin accumulation in tomato fruit (Cao et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Combined QTL-Seq and Traditional Linkage Analysis to Identify Candidate Genes for Purple Skin of Radish Fleshy Taproots

Liu

Wang

et al. 2019

Front. Genet.

Taproot skin color is a crucial visual and nutritional quality trait of radish, and purple skin is most attractive to consumers. However, the genetic mechanism underlying this character is unknown. Herein, F2 segregating populations were constructed to investigate radish genomic regions with purple skin genes. Segregation analysis suggested that pigment presence was controlled by one dominant gene, Rsps. A bulk segregant approach coupled to whole-genome sequencing (QTL-seq) and classical linkage mapping narrowed the Rsps location to a 238.51-kb region containing 18 genes. A gene in this region, designated RsMYB1.1 (an Arabidopsis PAP1 homolog), was a likely candidate gene because semiquantitative RT-PCR and quantitative real-time PCR revealed RsMYB1.1 expression in only purple-skinned genotypes, sequence variation was found between white- and purple-skinned radishes, and an InDel marker in this gene correctly predicted taproot skin color. Furthermore, four RsMYB1.1 homologs (RsMYB1.1-1.4) were found in “XYB36-2” radish. RsMYB1.1 and the previously mapped and cloned RsMYB1.4 (contributing to red skin) were located on different chromosomes and in different subclades of a phylogenetic tree; thus, they are different genes. These findings provide insight into the complex anthocyanin biosynthesis regulation in radish and information for molecular breeding to improve the anthocyanin content and appearance of radish taproots.