The formation of wood is affected by the growing season and the environment.Ring-porous tree species have distinct earlywood-latewood differences.However,it is not clear how early wood and latewood respond to drought ...The formation of wood is affected by the growing season and the environment.Ring-porous tree species have distinct earlywood-latewood differences.However,it is not clear how early wood and latewood respond to drought and the differences in adaptation.Therefore,based on the analyses of phenology,growth,and xylem development over a year,xylem development in Fraxinus mandshurica was divided into earlyw ood,transition,and latewood stages.Variation patterns of 38 wood indices from 31 genotypes indicated that the formation of wood tissues was inhibited,and the proportion of xylem cells was affected by drought at each stage.However,soluble sugar affected osmotic regulation only during drought across early wood and transition stages.To maintain water and nutrient transport during drought and to resist embolism risk,drought in the early wood stage leads to varying degrees of early wood vessel diameter reduction,with pits enlarging to compensate.In contrast,during the late wood stage,drought causes latewood vessel diameter to increase and pits to shrink accordingly.In addition,the results indicate that several wood indices correlate with drought resistance at each stage,but early wood vessel diameter,soluble sugar,and latewood ves sel diameters exhibited the strongest correlations in the early wood,transition,and latewood stages.These findings provide clues to understanding plant survival strategies under drought stress and are of significance for plant ecology research on the growth and adaptation of tree species under climate change.展开更多
Glycosyltransferases(GTs)constitute a diverse family of synthetic polysaccharides with important roles in plant growth and development.This study characterized the GT14 family gene BpGT14;6 of birch(Betula platyphylla...Glycosyltransferases(GTs)constitute a diverse family of synthetic polysaccharides with important roles in plant growth and development.This study characterized the GT14 family gene BpGT14;6 of birch(Betula platyphylla Suk.).BpGT14;6 was highly expressed in the xylem and stem of birch plants.Subcellular localization analysis suggested that BpGT14;6 was located in the Golgi apparatus.RNA interference(RNAi)silencing of BpGT14;6 revealed lower lignin,hemicellulose,and pectin contents compared to wild type(WT)plants.Following treatment with abscisic acid(ABA),compared to WT plants,RNAi-BpGT14;6 plants were more sensitive to ABA,suffered more membrane lipid damage,and accumulated more reactive oxygen species.The inhibition of BpGT14;6 expression narrowed the birch xylem and thinned the cell wall,and increased the expression of multiple ABA pathway-related genes in birch under ABA treatment.Compared to WT plants,RNAi-BpGT14;6 plants showed increased tolerance to drought stress.Promoter analysis revealed that BpGT14;6 is involved in hormone regulation and adaptation to adversity.Using the 1156 bp BpGT14;6 promoter as bait,two potential transcription factors,BpWRKY1 and BpARF2,were identified through Y1H screening that may regulate its expression.EMSA confirmed that BpWRKY1 and BpARF2 can directly bind to the W-BOX and AuxRE cis-acting elements on the BpGT14;6 promoter,respectively.The collective results suggest that BpGT14;6 affects birch xylem and cell wall development by affecting lignin,hemicellulose,and pectin synthesis,and participates in birch adversity adaptation.展开更多
DNA methylation is widespread in plants and associated with plant development and defense mechanisms.However,the relationship between DNA methylation and plant secondary metabolism has rarely been reported.Here,when b...DNA methylation is widespread in plants and associated with plant development and defense mechanisms.However,the relationship between DNA methylation and plant secondary metabolism has rarely been reported.Here,when birch suspension cells were treated with 5-azacytidine(5-azaC),which blocks DNA methylation,triterpenoid accumulation was significantly promoted and antioxidant and defense enzymatic activity changed.For studying triterpenoid accumulation,0.1 mM azaC was optimal.A qRT-PCR assay revealed increased expression of genes encoding key triterpenoid biosynthetic enzymes.Evaluation of methylation polymorphisms at CCGG sites showed that the methylation level was lower in cells treated with 5-azaC.These results demonstrated that 5-azaC treatment led to an increase in the production of triterpenoids in cell cultures through a mechanism that involved in DNA methylation,which resulted in the induction of genes encoding the key enzymes.The study provides evidence of a relationship between DNA methylation and regulation of secondary metabolism.展开更多
基金supported by the National Key R&D Program of China(2021YFD2200303)the National Natural Science Foundation of China(32271903,U24A20428)。
文摘The formation of wood is affected by the growing season and the environment.Ring-porous tree species have distinct earlywood-latewood differences.However,it is not clear how early wood and latewood respond to drought and the differences in adaptation.Therefore,based on the analyses of phenology,growth,and xylem development over a year,xylem development in Fraxinus mandshurica was divided into earlyw ood,transition,and latewood stages.Variation patterns of 38 wood indices from 31 genotypes indicated that the formation of wood tissues was inhibited,and the proportion of xylem cells was affected by drought at each stage.However,soluble sugar affected osmotic regulation only during drought across early wood and transition stages.To maintain water and nutrient transport during drought and to resist embolism risk,drought in the early wood stage leads to varying degrees of early wood vessel diameter reduction,with pits enlarging to compensate.In contrast,during the late wood stage,drought causes latewood vessel diameter to increase and pits to shrink accordingly.In addition,the results indicate that several wood indices correlate with drought resistance at each stage,but early wood vessel diameter,soluble sugar,and latewood ves sel diameters exhibited the strongest correlations in the early wood,transition,and latewood stages.These findings provide clues to understanding plant survival strategies under drought stress and are of significance for plant ecology research on the growth and adaptation of tree species under climate change.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.31870588 and 31200463)The Innovation Project of State Key Laboratory of Tree Genetics and Breeding(Northeast Forestry University)(Grant No.2022A03)Heilongjiang Touyan Innovation Team Program.
文摘Glycosyltransferases(GTs)constitute a diverse family of synthetic polysaccharides with important roles in plant growth and development.This study characterized the GT14 family gene BpGT14;6 of birch(Betula platyphylla Suk.).BpGT14;6 was highly expressed in the xylem and stem of birch plants.Subcellular localization analysis suggested that BpGT14;6 was located in the Golgi apparatus.RNA interference(RNAi)silencing of BpGT14;6 revealed lower lignin,hemicellulose,and pectin contents compared to wild type(WT)plants.Following treatment with abscisic acid(ABA),compared to WT plants,RNAi-BpGT14;6 plants were more sensitive to ABA,suffered more membrane lipid damage,and accumulated more reactive oxygen species.The inhibition of BpGT14;6 expression narrowed the birch xylem and thinned the cell wall,and increased the expression of multiple ABA pathway-related genes in birch under ABA treatment.Compared to WT plants,RNAi-BpGT14;6 plants showed increased tolerance to drought stress.Promoter analysis revealed that BpGT14;6 is involved in hormone regulation and adaptation to adversity.Using the 1156 bp BpGT14;6 promoter as bait,two potential transcription factors,BpWRKY1 and BpARF2,were identified through Y1H screening that may regulate its expression.EMSA confirmed that BpWRKY1 and BpARF2 can directly bind to the W-BOX and AuxRE cis-acting elements on the BpGT14;6 promoter,respectively.The collective results suggest that BpGT14;6 affects birch xylem and cell wall development by affecting lignin,hemicellulose,and pectin synthesis,and participates in birch adversity adaptation.
基金The work was supported by The Fundamental Research Funds for the Central Universities(2572017EA05)the National Natural Science Foundation of China(31870588).
文摘DNA methylation is widespread in plants and associated with plant development and defense mechanisms.However,the relationship between DNA methylation and plant secondary metabolism has rarely been reported.Here,when birch suspension cells were treated with 5-azacytidine(5-azaC),which blocks DNA methylation,triterpenoid accumulation was significantly promoted and antioxidant and defense enzymatic activity changed.For studying triterpenoid accumulation,0.1 mM azaC was optimal.A qRT-PCR assay revealed increased expression of genes encoding key triterpenoid biosynthetic enzymes.Evaluation of methylation polymorphisms at CCGG sites showed that the methylation level was lower in cells treated with 5-azaC.These results demonstrated that 5-azaC treatment led to an increase in the production of triterpenoids in cell cultures through a mechanism that involved in DNA methylation,which resulted in the induction of genes encoding the key enzymes.The study provides evidence of a relationship between DNA methylation and regulation of secondary metabolism.
