Lily(Lilium spp.) is an important ornamental flower, which is mainly propagated by bulbs. Cell wall invertases(CWINs), which catalyze the irreversibly conversion of sucrose into glucose and fructose in the extracellul...Lily(Lilium spp.) is an important ornamental flower, which is mainly propagated by bulbs. Cell wall invertases(CWINs), which catalyze the irreversibly conversion of sucrose into glucose and fructose in the extracellular space, are key enzymes participating in sucrose allocation in higher plants. Previous studies have shown that CWINs play an essential role in bulblet initiation process in bulbous crops, but the underlying molecular mechanism remains unclear. Here, a CWIN gene of Lilium brownii var. giganteum(Lbg) was identified and amplified from genomic DNA. Quantitative RT-PCR assays revealed that the expression level of LbgCWIN1 was highly upregulated exactly when the endogenous starch degraded in non-sucrose medium during in vitro bulblet initiation in Lbg. Phylogenetic relationship, motif, and domain analysis of LbgCWIN1 protein and CWINs in other plant species showed that all sequences of these CWIN proteins were highly conserved. The promoter sequence of LbgCWIN1 possessed a number of alpha-amylase-, phytohormone-, light-and stress-responsive cis-elements. Meanwhile, β-glucuronidase(GUS) assay showed that the 459 bp upstream fragment from the translational start site displayed maximal promoter activity. These results revealed that LbgCWIN1 might function in the process of in vitro bulblet initiation and be in the response to degradation of endogenous starch.展开更多
The layered structural parameters have been reported to be critical for tuning the tensile properties of laminated metals.Here,we investigated the effects of the thickness ratio(rc/f)of coarse-grained layers(CLs)to fi...The layered structural parameters have been reported to be critical for tuning the tensile properties of laminated metals.Here,we investigated the effects of the thickness ratio(rc/f)of coarse-grained layers(CLs)to fine-grained layers(FLs)on the enhanced ductility of the laminated Al.The local strain evolution demonstrates that the strain delocalization ability of laminated Al is improved with the decrease of rc/f.The interfacial strain gradients,which can produce extra work hardening,gradually approach and cover the CLs with the rc/fdecreasing,explaining the trend of uniform elongation in laminated Al with various rc/f.The integrated fracture morphology characterization reveals that the increase of the rc/fleads to an improvement in the tolerance of the interfacial microcracks,which is corresponding to the variation of fracture elongation in the laminated Al.Moreover,there is an evident transition of transverse propagation path of interfacial microcracks from the CLs to FLs with increasing the rc/f.Based on a geometrical criterion of microcracks connectivity,the preferential transverse propagation path of interfacial microcracks in these laminated Al was rationalized.The calculation based on this criterion also predicted the critical rc/fcorresponding to the optimal combination of strength and fracture elongation.This work deepens the understanding of the role of structural parameters of laminated metals in achieving the strength and ductility synergy.展开更多
Starch is the predominant compound in bulb scales,and previous studies have shown that bulblet development is closely associated with starch enrichment.However,how starch synthesis affects bulbification at the molecul...Starch is the predominant compound in bulb scales,and previous studies have shown that bulblet development is closely associated with starch enrichment.However,how starch synthesis affects bulbification at the molecular level is unclear.In this study,we demonstrate that Lilium brownii var.giganteum,a wild lily with a giant bulb in nature,and L.brownii,the native species,have different starch levels and characteristics according to cytological and ultra-structural observations.We cloned the complete sequence of three key gene-encoding enzymes(LbgAGPS,LbgGBSS,and LbgSSⅢ)during starch synthesis by rapid amplification of 5’and 3’complementary DNA(cDNA)ends(RACE)technology.Bioinformatics analysis revealed that the proteins deduced by these genes contain the canonical conserved domains.Constructed phylogenetic trees confirmed the evolutionary relationships with proteins from other species,including monocotyledons and dicotyledons.The transcript levels of various tissues and time course samples obtained during bulblet development uncovered relatively high expression levels in bulblets and gradual increase expression accompanying bulblet growth.Moreover,a set of single nucleotide polymorphisms(SNPs)was discovered in the AGPS genes of four lily genotypes,and a purifying selection fashion was predicted according to the non-synonymous/synonymous(Ka/Ks)values.Taken together,our results suggested that key starch-synthesizing genes might play important roles in bulblet development and lead to distinctive phenotypes in bulblet size.展开更多
As one of the heterostructures,the layered structure has attracted extensive research interests as it could regulate the deformation mechanisms[1-3].A remarkable combination of strength and ductility has been achieved...As one of the heterostructures,the layered structure has attracted extensive research interests as it could regulate the deformation mechanisms[1-3].A remarkable combination of strength and ductility has been achieved in layered metals,including CuCu[4-6],Cu-Ni[7],Cu-Al[8,9],Cu-Ti[10],Ti-Ti[11,12],and Ti-Al[13-15].During deformation,mechanical mismatch(discrepancies of yield strength,work hardening,etc.)between component layers leads to mutual constraints,which generates local stress and local strain that deviate from the applied counterparts[16-18].As a result,the activation of additional deformation mechanisms is promoted in layered metals,such as slip systems with low Schmid factor or high critical resolved shear stress[19,20].展开更多
基金financially supported by the National Natural Science Foundation of China (Grant Nos.32101571,32002071)the Zhejiang Science and Technology Major Program on Agricultural New Variety Breeding (Grant No.2021C02071-6)。
文摘Lily(Lilium spp.) is an important ornamental flower, which is mainly propagated by bulbs. Cell wall invertases(CWINs), which catalyze the irreversibly conversion of sucrose into glucose and fructose in the extracellular space, are key enzymes participating in sucrose allocation in higher plants. Previous studies have shown that CWINs play an essential role in bulblet initiation process in bulbous crops, but the underlying molecular mechanism remains unclear. Here, a CWIN gene of Lilium brownii var. giganteum(Lbg) was identified and amplified from genomic DNA. Quantitative RT-PCR assays revealed that the expression level of LbgCWIN1 was highly upregulated exactly when the endogenous starch degraded in non-sucrose medium during in vitro bulblet initiation in Lbg. Phylogenetic relationship, motif, and domain analysis of LbgCWIN1 protein and CWINs in other plant species showed that all sequences of these CWIN proteins were highly conserved. The promoter sequence of LbgCWIN1 possessed a number of alpha-amylase-, phytohormone-, light-and stress-responsive cis-elements. Meanwhile, β-glucuronidase(GUS) assay showed that the 459 bp upstream fragment from the translational start site displayed maximal promoter activity. These results revealed that LbgCWIN1 might function in the process of in vitro bulblet initiation and be in the response to degradation of endogenous starch.
基金financially supported by the National Key Research&Development Program of China(Nos.2020YFA0405900 and 2017YFA0403803)the National Natural Science Foundation of China(Nos.51927801 and 51971075)the Natural Science Foundation of Jiangsu Province(No.BK20202010)。
文摘The layered structural parameters have been reported to be critical for tuning the tensile properties of laminated metals.Here,we investigated the effects of the thickness ratio(rc/f)of coarse-grained layers(CLs)to fine-grained layers(FLs)on the enhanced ductility of the laminated Al.The local strain evolution demonstrates that the strain delocalization ability of laminated Al is improved with the decrease of rc/f.The interfacial strain gradients,which can produce extra work hardening,gradually approach and cover the CLs with the rc/fdecreasing,explaining the trend of uniform elongation in laminated Al with various rc/f.The integrated fracture morphology characterization reveals that the increase of the rc/fleads to an improvement in the tolerance of the interfacial microcracks,which is corresponding to the variation of fracture elongation in the laminated Al.Moreover,there is an evident transition of transverse propagation path of interfacial microcracks from the CLs to FLs with increasing the rc/f.Based on a geometrical criterion of microcracks connectivity,the preferential transverse propagation path of interfacial microcracks in these laminated Al was rationalized.The calculation based on this criterion also predicted the critical rc/fcorresponding to the optimal combination of strength and fracture elongation.This work deepens the understanding of the role of structural parameters of laminated metals in achieving the strength and ductility synergy.
基金the National Natural Science Foundation of China(No.31772337)the Lishui Research Fund(No.2020zdhz03)+1 种基金the China Postdoctoral Science Foundation(No.2017M612005)the National Key Research and Development Program of China(No.2018YFD1000401)。
文摘Starch is the predominant compound in bulb scales,and previous studies have shown that bulblet development is closely associated with starch enrichment.However,how starch synthesis affects bulbification at the molecular level is unclear.In this study,we demonstrate that Lilium brownii var.giganteum,a wild lily with a giant bulb in nature,and L.brownii,the native species,have different starch levels and characteristics according to cytological and ultra-structural observations.We cloned the complete sequence of three key gene-encoding enzymes(LbgAGPS,LbgGBSS,and LbgSSⅢ)during starch synthesis by rapid amplification of 5’and 3’complementary DNA(cDNA)ends(RACE)technology.Bioinformatics analysis revealed that the proteins deduced by these genes contain the canonical conserved domains.Constructed phylogenetic trees confirmed the evolutionary relationships with proteins from other species,including monocotyledons and dicotyledons.The transcript levels of various tissues and time course samples obtained during bulblet development uncovered relatively high expression levels in bulblets and gradual increase expression accompanying bulblet growth.Moreover,a set of single nucleotide polymorphisms(SNPs)was discovered in the AGPS genes of four lily genotypes,and a purifying selection fashion was predicted according to the non-synonymous/synonymous(Ka/Ks)values.Taken together,our results suggested that key starch-synthesizing genes might play important roles in bulblet development and lead to distinctive phenotypes in bulblet size.
基金financially supported by the National Key Research&Development Plan(Nos.2020YFA0405900,2017YFA0403803,2017YFB0703103)the National Natural Science Foundation of China(Nos.51927801 and 52171117)the Natural Science Foundation of Jiangsu Province(No.BK20202010)。
文摘As one of the heterostructures,the layered structure has attracted extensive research interests as it could regulate the deformation mechanisms[1-3].A remarkable combination of strength and ductility has been achieved in layered metals,including CuCu[4-6],Cu-Ni[7],Cu-Al[8,9],Cu-Ti[10],Ti-Ti[11,12],and Ti-Al[13-15].During deformation,mechanical mismatch(discrepancies of yield strength,work hardening,etc.)between component layers leads to mutual constraints,which generates local stress and local strain that deviate from the applied counterparts[16-18].As a result,the activation of additional deformation mechanisms is promoted in layered metals,such as slip systems with low Schmid factor or high critical resolved shear stress[19,20].