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
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
In situ scanning electron microscope(SEM)characterization have enabled the stretching,compression,and bending of micro/nanomaterials and have greatly expanded our understanding of small-scale phenomena.However,as one ...In situ scanning electron microscope(SEM)characterization have enabled the stretching,compression,and bending of micro/nanomaterials and have greatly expanded our understanding of small-scale phenomena.However,as one of the fundamental approaches for material analytics,torsion tests at a small scale remain a major challenge due to the lack of an ultrahigh precise torque sensor and the delicate sample assembly strategy.Herein,we present a microelectromechanical resonant torque sensor with an ultrahigh resolution of up to 4.78 fN∙m within an ultrawide dynamic range of 123 dB.Moreover,we propose a nanorobotic system to realize the precise assembly of microscale specimens with nanoscale positioning accuracy and to conduct repeatable in situ pure torsion tests for the first time.As a demonstration,we characterized the mechanical properties of Si microbeams through torsion tests and found that these microbeams were five-fold stronger than their bulk counterparts.The proposed torsion characterization system pushes the limit of mechanical torsion tests,overcomes the deficiencies in current in situ characterization techniques,and expands our knowledge regarding the behavior of micro/nanomaterials at various loads,which is expected to have significant implications for the eventual development and implementation of materials science.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supported by the National Key R&D Program of China(No.2018YFB2002303)the National Natural Science Foundation of China(Nos.52075432,61922093,U1813211,6207330)+1 种基金Hong Kong RGC General Research Fund CityU(11211720)ShenZhen(China)Key Basic Research Project(No.JCYJ20200109114827177).
文摘In situ scanning electron microscope(SEM)characterization have enabled the stretching,compression,and bending of micro/nanomaterials and have greatly expanded our understanding of small-scale phenomena.However,as one of the fundamental approaches for material analytics,torsion tests at a small scale remain a major challenge due to the lack of an ultrahigh precise torque sensor and the delicate sample assembly strategy.Herein,we present a microelectromechanical resonant torque sensor with an ultrahigh resolution of up to 4.78 fN∙m within an ultrawide dynamic range of 123 dB.Moreover,we propose a nanorobotic system to realize the precise assembly of microscale specimens with nanoscale positioning accuracy and to conduct repeatable in situ pure torsion tests for the first time.As a demonstration,we characterized the mechanical properties of Si microbeams through torsion tests and found that these microbeams were five-fold stronger than their bulk counterparts.The proposed torsion characterization system pushes the limit of mechanical torsion tests,overcomes the deficiencies in current in situ characterization techniques,and expands our knowledge regarding the behavior of micro/nanomaterials at various loads,which is expected to have significant implications for the eventual development and implementation of materials science.
