Fig fruit firmness decreases rapidly during ripening and after harvest,resulting in poor storability and transportation loss,which severely restricts development of the fresh fig industry.APETALA2/ethylene-responsive ...Fig fruit firmness decreases rapidly during ripening and after harvest,resulting in poor storability and transportation loss,which severely restricts development of the fresh fig industry.APETALA2/ethylene-responsive factor(AP2/ERF)transcription factors are downstream components of the ethylene-signaling pathway that play crucial roles in quality formation during fruit ripening.In this study,Ficus carica(Fc)ERF12 was clustered in repressor subfamily VIII of ERFs through phylogenetic analysis,and further recruited by its two EAR motifs and expression pattern during fig ripening.DNA affinity purification sequencing analysis indicated that FcERF12 binds to the promoter or gene body regions of multiple ripening-related genes,including cell wall-modification genes FcPG,FcXTH and FcPME,and ethylene-biosynthesis genes FcACS and FcACO.Yeast two-hybrid assay demonstrated that FcERF12 interacts with TOPLESS(TPL)co-repressors FcTPL1,FcTPL4 and FcTPL5,and histone deacetylases FcHDA6 and FcHDA19;interaction with FcTPL4 and FcTPL5 relied on the C-terminal EAR motif.Overexpressing FcERF12 in tomato did not change fruit size or yield,but resulted in an 18.37%increment in fruit firmness and a 49.62%reduction in ethylene-release rate at fruit ripening,accompanied by a significant decrease in seed number per fruit.Transcriptomic analysis revealed downregulation of tomato cell wallmodification genes SlPL,SlEXP and SlPG,and ethylene-synthesis genes SlACO and SlACS.Metabolomic profiling identified 82 differentially accumulated flavonoid metabolites,61 of them showing significantly decreased contents.Taken together,our results exhibit the negative regulatory role of FcERF12 in fig ethylene-signal transduction,providing new information on precise control of fruit firmness and other quality traits at ripening.展开更多
Fig(Ficus carica L.)with purple-red peel cultivars are popular among consumers and exhibit better storability.While DNA methylation influences fruit ripening and color development,its specific role in fig fruit remain...Fig(Ficus carica L.)with purple-red peel cultivars are popular among consumers and exhibit better storability.While DNA methylation influences fruit ripening and color development,its specific role in fig fruit remains unclear.This study explores the impact of DNA methylation on the fig peel coloration.Enzymatic colorimetric detection revealed that the level of‘Purple Peel’fig DNA methylation decreases with fig fruit ripening and coloring.Treatment of young fruit with the DNA-methylation inhibitor azacytidine induced peel coloration,suggesting that a decrease in DNA-methylation level promotes fig peel coloration.Seven members of DNA methyltransferases and three members of DNA demethylases were identified from a high-level fig genome,highlighting FcMET1 and FcDRM2 as stable proteins,ensuring functional expression.Reference to the Arabidopsis protein interaction network map predicted that FcMET1 is in a central position,suggesting a crucial regulatory role in multiple biological processes.Correlation analysis revealed a positive correlation between FcMET1 expression during peel development and the level of total DNA methylation.Weighted gene co-expression network analysis identified co-expression of FcMET1 with the color-related transcription factors MYB,bHLH and WD40,as well as with eight structural genes in the flavonoid-biosynthesis pathway.The expression of FcUFGT3 was negatively correlated with that of FcMET1.McrBC-PCR and Bisulfite Sequencing detection showed that a low methylation level of the FcUFGT3 promoter corresponds with its high expression in colored fig.This investigation of the mechanism of DNA methylation provides a theoretical basis for understanding the role of DNA-methylation modifications in fig ripening and coloring.展开更多
Dry fig is a traditional healthy snack and has important economic value in a number of Mediterranean and Middle Eastern countries.Cultivars with no anthocyanin accumulation in the fruit peel are preferred for dry fig ...Dry fig is a traditional healthy snack and has important economic value in a number of Mediterranean and Middle Eastern countries.Cultivars with no anthocyanin accumulation in the fruit peel are preferred for dry fig production.R2R3-MYB transcription factors have promotive or repressive regulatory roles in plant anthocyanin biosynthesis.In this study,113 R2R3-MYB genes were identified in Ficus carica,3 of which were assigned to the S4 subfamily of flavonoid-biosynthesis repressors.FcMYB57 was further recruited as a candidate anthocyaninbiosynthesis repressor based on its sequence features and expression,which was significantly negatively correlated with that of anthocyanin-biosynthesis structural genes.Transient overexpression of FcMYB57 in strawberry totally inhibited fruit pigmentation and significantly increased fruit firmness.The metabolomic analysis confirmed a significant reduction in the contents of cyanidin-3-O-glucoside and pelargonidin-3-O-glucoside,as well as other flavonoids,and transmission electron microscopy revealed an increment in cell-wall thickness.Transcriptome analysis showed downregulation of anthocyanin-biosynthesis structural genes and upregulation of genes related to xylan synthesis.Yeast one-hybrid and dual luciferase assays demonstrated a negative regulatory effect of FcMYB57 on the promoter of FcUFGT3(UDP glucose-flavonoid 3-O-glcosyl-transferase).Yeast two-hybrid assay showed that FcMYB57 does not interact with FcbHLH42,3,14,MYC2,or FcTTG1,all of which have a previously identified or predicted role in flavonoid biosynthesis,however,interaction was detected with FcTPL(Topless),suggesting that FcMYB57 serves as an active repressor of anthocyanin biosynthesis.This is the first identification of an anthocyaninbiosynthesis repressor in fig,with a possible role in fig fruit quality.展开更多
基金supported by the key research project for fig development of Weiyuan County(Grant No.1002-69199007),China.
文摘Fig fruit firmness decreases rapidly during ripening and after harvest,resulting in poor storability and transportation loss,which severely restricts development of the fresh fig industry.APETALA2/ethylene-responsive factor(AP2/ERF)transcription factors are downstream components of the ethylene-signaling pathway that play crucial roles in quality formation during fruit ripening.In this study,Ficus carica(Fc)ERF12 was clustered in repressor subfamily VIII of ERFs through phylogenetic analysis,and further recruited by its two EAR motifs and expression pattern during fig ripening.DNA affinity purification sequencing analysis indicated that FcERF12 binds to the promoter or gene body regions of multiple ripening-related genes,including cell wall-modification genes FcPG,FcXTH and FcPME,and ethylene-biosynthesis genes FcACS and FcACO.Yeast two-hybrid assay demonstrated that FcERF12 interacts with TOPLESS(TPL)co-repressors FcTPL1,FcTPL4 and FcTPL5,and histone deacetylases FcHDA6 and FcHDA19;interaction with FcTPL4 and FcTPL5 relied on the C-terminal EAR motif.Overexpressing FcERF12 in tomato did not change fruit size or yield,but resulted in an 18.37%increment in fruit firmness and a 49.62%reduction in ethylene-release rate at fruit ripening,accompanied by a significant decrease in seed number per fruit.Transcriptomic analysis revealed downregulation of tomato cell wallmodification genes SlPL,SlEXP and SlPG,and ethylene-synthesis genes SlACO and SlACS.Metabolomic profiling identified 82 differentially accumulated flavonoid metabolites,61 of them showing significantly decreased contents.Taken together,our results exhibit the negative regulatory role of FcERF12 in fig ethylene-signal transduction,providing new information on precise control of fruit firmness and other quality traits at ripening.
基金supported by 111 Project(Grant No.B17043)China Postdoctoral Science Foundation(Grant No.2022M723425).
文摘Fig(Ficus carica L.)with purple-red peel cultivars are popular among consumers and exhibit better storability.While DNA methylation influences fruit ripening and color development,its specific role in fig fruit remains unclear.This study explores the impact of DNA methylation on the fig peel coloration.Enzymatic colorimetric detection revealed that the level of‘Purple Peel’fig DNA methylation decreases with fig fruit ripening and coloring.Treatment of young fruit with the DNA-methylation inhibitor azacytidine induced peel coloration,suggesting that a decrease in DNA-methylation level promotes fig peel coloration.Seven members of DNA methyltransferases and three members of DNA demethylases were identified from a high-level fig genome,highlighting FcMET1 and FcDRM2 as stable proteins,ensuring functional expression.Reference to the Arabidopsis protein interaction network map predicted that FcMET1 is in a central position,suggesting a crucial regulatory role in multiple biological processes.Correlation analysis revealed a positive correlation between FcMET1 expression during peel development and the level of total DNA methylation.Weighted gene co-expression network analysis identified co-expression of FcMET1 with the color-related transcription factors MYB,bHLH and WD40,as well as with eight structural genes in the flavonoid-biosynthesis pathway.The expression of FcUFGT3 was negatively correlated with that of FcMET1.McrBC-PCR and Bisulfite Sequencing detection showed that a low methylation level of the FcUFGT3 promoter corresponds with its high expression in colored fig.This investigation of the mechanism of DNA methylation provides a theoretical basis for understanding the role of DNA-methylation modifications in fig ripening and coloring.
基金supported by the key research project for fig development of Weiyuan County(Grant No.1002-69199007),China.
文摘Dry fig is a traditional healthy snack and has important economic value in a number of Mediterranean and Middle Eastern countries.Cultivars with no anthocyanin accumulation in the fruit peel are preferred for dry fig production.R2R3-MYB transcription factors have promotive or repressive regulatory roles in plant anthocyanin biosynthesis.In this study,113 R2R3-MYB genes were identified in Ficus carica,3 of which were assigned to the S4 subfamily of flavonoid-biosynthesis repressors.FcMYB57 was further recruited as a candidate anthocyaninbiosynthesis repressor based on its sequence features and expression,which was significantly negatively correlated with that of anthocyanin-biosynthesis structural genes.Transient overexpression of FcMYB57 in strawberry totally inhibited fruit pigmentation and significantly increased fruit firmness.The metabolomic analysis confirmed a significant reduction in the contents of cyanidin-3-O-glucoside and pelargonidin-3-O-glucoside,as well as other flavonoids,and transmission electron microscopy revealed an increment in cell-wall thickness.Transcriptome analysis showed downregulation of anthocyanin-biosynthesis structural genes and upregulation of genes related to xylan synthesis.Yeast one-hybrid and dual luciferase assays demonstrated a negative regulatory effect of FcMYB57 on the promoter of FcUFGT3(UDP glucose-flavonoid 3-O-glcosyl-transferase).Yeast two-hybrid assay showed that FcMYB57 does not interact with FcbHLH42,3,14,MYC2,or FcTTG1,all of which have a previously identified or predicted role in flavonoid biosynthesis,however,interaction was detected with FcTPL(Topless),suggesting that FcMYB57 serves as an active repressor of anthocyanin biosynthesis.This is the first identification of an anthocyaninbiosynthesis repressor in fig,with a possible role in fig fruit quality.
