This review is concerned with the mechanisms controlling fruit softening.Master genetic regulators switch on the ripening programme and the regulatory pathway branches downstream,with separate controls for distinct qu...This review is concerned with the mechanisms controlling fruit softening.Master genetic regulators switch on the ripening programme and the regulatory pathway branches downstream,with separate controls for distinct quality attributes such as colour,flavour,texture,and aroma.Ethylene plays a critical role as a ripening hormone and is implicated in controlling different facets of ripening,including texture change,acting through a range of transcriptional regulators,and this signalling can be blocked using 1-methylcyclopropene.A battery of at least seven cell-wall-modifying enzymes,most of which are synthesized de novo during ripening,cause major alterations in the structure and composition of the cell wall components and contribute to the softening process.Significant differences between fruits may be related to the precise structure and composition of their cell walls and the enzymes recruited to the ripening programme during evolution.Attempts to slow texture change and reduce fruit spoilage by delaying the entire ripening process can often affect negatively other aspects of quality,and low temperatures,in particular,can have deleterious effects on texture change.Gene silencing has been used to probe the function of individual genes involved in different aspects of ripening,including colour,flavour,ethylene synthesis,and particularly texture change.The picture that emerges is that softening is a multi-genic trait,with some genes making a more important contribution than others.In future,it may be possible to control texture genetically to produce fruits more suitable for our needs.展开更多
在含有儿茶素的培养液中棉枯萎病菌(Fusarium oxysporum f. sp. vasinfectum)的多聚半乳糖醛酸酶(PG)和果胶裂解酶(PL)活性明显降低。儿茶素可明显抑制初步纯化的PG和PL活性以及它们对棉苗组织的浸软作用。对棉苗组织中儿茶素含量的测...在含有儿茶素的培养液中棉枯萎病菌(Fusarium oxysporum f. sp. vasinfectum)的多聚半乳糖醛酸酶(PG)和果胶裂解酶(PL)活性明显降低。儿茶素可明显抑制初步纯化的PG和PL活性以及它们对棉苗组织的浸软作用。对棉苗组织中儿茶素含量的测定结果表明:抗病品种棉苗组织中儿茶素含量较高;氟乐灵处理可诱发棉苗产生对枯萎病的诱导抗性,同时也提高棉苗组织中的儿茶素的含量;枯萎病菌侵染后棉苗组织中儿茶素含量明显升高,以抗病品种棉苗和氟乐灵诱发处理棉苗组织中儿茶素含量的增加更为明显。棉苗组织提取液中的酚类物质可抑制PG和PL的活性,且证明这种抑制作用主要是由儿茶素引起。提取液对PG和PL活性的抑制作用与棉苗组织中儿茶素的含量呈直接的正相关关系。因此,作者认为棉苗组织中的儿茶素可能通过对病菌PG和PL等胞壁降解酶的抑制而与棉花对枯萎病的抗病性及氟乐灵诱发的诱导抗性有关。展开更多
Pectin is a major constituent of the plant cell wall.Pectate lyase(PEL,EC 4.2.2.2)uses anti-β-elimination chemistry to cleave theα-1,4 glycosidic linkage in the homogalacturonan region of pectin.However,limited info...Pectin is a major constituent of the plant cell wall.Pectate lyase(PEL,EC 4.2.2.2)uses anti-β-elimination chemistry to cleave theα-1,4 glycosidic linkage in the homogalacturonan region of pectin.However,limited information is available on the comprehensive and evolutionary analysis of PELs in the Malvaceae.In this study,we identified 597PEL genes from 10 Malvaceae species.Phylogenetic and motif analyses revealed that these PELs are classified into six subfamilies:Clades I,II,III,IV,Va,and Vb.The two largest subfamilies,Clades I and II,contained 237 and222 PEL members,respectively.The members of Clades Va and Vb only contained four or five motifs,far fewer than the other subfamilies.Gene duplication analysis showed that segmental duplication played a crucial role in the expansion of the PEL gene family in Gossypium species.The PELs from Clades I,IV,Va,and Vb were expressed during the fiber elongation stage,but nearly all PEL genes from Clades II and III showed no expression in any of the investigated fiber developmental stages.We further performed single-gene haplotype association analysis in 2,001G.hirsutum accessions and 229 G.barbadense accessions.Interestingly,14 PELs were significantly associated with fiber length and strength traits in G.barbadense with superior fiber quality,while only eight GhPEL genes were found to be significantly associated with fiber quality traits in G.hirsutum.Our findings provide important information for further evolutionary and functional research on the PEL gene family members and their potential use for fiber quality improvement in cotton.展开更多
The soybean cyst nematode, Heterodeara glycines, is a serious pathogen of soybean, and reported to be the host of a wide range of Fabaceae. In the present study, the host specificity and reproductivity of two populati...The soybean cyst nematode, Heterodeara glycines, is a serious pathogen of soybean, and reported to be the host of a wide range of Fabaceae. In the present study, the host specificity and reproductivity of two populations of H. glycines collected from soybean and tobacco were identified and characterized. The comparative identity between β-1,4-endoglucanase, pectate lyase and chorismate mutase of H. glycines parasitizing on soybean and tobacco were 99, 97 and 98%, respectively. The qR T-PCR analysis indicated that the expression of pectate lyase 2 gene was significantly higher in second-stage juveniles of H. glycines Henan population parasitizing on tobacco than that of H. glycines Shanxi population parasitizing on soybean. In addition, the pectic acid content of cell wall was significantly higher(45%) in the roots of tobacco than the roots of soybean. Our results indicate that the changes in transcript parasitism genes may be a result of long-term evolution illustrating how a plant-parasitic nematode adapts to the host environment for optimal infestation and survival.展开更多
Rice panicle apical abortion(PAA)is a detrimental agronomic trait resulting in spikelet number reduction and yield loss.To understand its underlying molecular mechanism,we identified one recessive PAA mutant tutou2 fr...Rice panicle apical abortion(PAA)is a detrimental agronomic trait resulting in spikelet number reduction and yield loss.To understand its underlying molecular mechanism,we identified one recessive PAA mutant tutou2 from the offspring of tissue cultures.The mutation locus was finely mapped to a 75-kb interval on the long arm of chromosome 10.Sequence analysis revealed a single nucleotide substitution of A to T at the 941 position of LOC_Os10g31910 in tutou2,resulting in an amino acid change from isoleucine to phenylalanine.Complementation analysis showed that the degenerated panicle phenotype in tutou2 was rescued in the transgenic lines.A phenotype similar to tutou2 can also be obtained by LOC_Os10g31910 knockout in wild-type rice.These results suggested that LOC_Os10 g31910 is the causative locus TUTOU2 responsible for the tutou2 PAA phenotype and probably also the locus of DEL1,previously documented as a leaf senescence gene.The significant phenotypic differences between del1 and tutou2 suggest that the locus DEL1/TUTOU2 plays roles in both leaf and panicle development which were not considered fully in previous studies.展开更多
文摘This review is concerned with the mechanisms controlling fruit softening.Master genetic regulators switch on the ripening programme and the regulatory pathway branches downstream,with separate controls for distinct quality attributes such as colour,flavour,texture,and aroma.Ethylene plays a critical role as a ripening hormone and is implicated in controlling different facets of ripening,including texture change,acting through a range of transcriptional regulators,and this signalling can be blocked using 1-methylcyclopropene.A battery of at least seven cell-wall-modifying enzymes,most of which are synthesized de novo during ripening,cause major alterations in the structure and composition of the cell wall components and contribute to the softening process.Significant differences between fruits may be related to the precise structure and composition of their cell walls and the enzymes recruited to the ripening programme during evolution.Attempts to slow texture change and reduce fruit spoilage by delaying the entire ripening process can often affect negatively other aspects of quality,and low temperatures,in particular,can have deleterious effects on texture change.Gene silencing has been used to probe the function of individual genes involved in different aspects of ripening,including colour,flavour,ethylene synthesis,and particularly texture change.The picture that emerges is that softening is a multi-genic trait,with some genes making a more important contribution than others.In future,it may be possible to control texture genetically to produce fruits more suitable for our needs.
文摘在含有儿茶素的培养液中棉枯萎病菌(Fusarium oxysporum f. sp. vasinfectum)的多聚半乳糖醛酸酶(PG)和果胶裂解酶(PL)活性明显降低。儿茶素可明显抑制初步纯化的PG和PL活性以及它们对棉苗组织的浸软作用。对棉苗组织中儿茶素含量的测定结果表明:抗病品种棉苗组织中儿茶素含量较高;氟乐灵处理可诱发棉苗产生对枯萎病的诱导抗性,同时也提高棉苗组织中的儿茶素的含量;枯萎病菌侵染后棉苗组织中儿茶素含量明显升高,以抗病品种棉苗和氟乐灵诱发处理棉苗组织中儿茶素含量的增加更为明显。棉苗组织提取液中的酚类物质可抑制PG和PL的活性,且证明这种抑制作用主要是由儿茶素引起。提取液对PG和PL活性的抑制作用与棉苗组织中儿茶素的含量呈直接的正相关关系。因此,作者认为棉苗组织中的儿茶素可能通过对病菌PG和PL等胞壁降解酶的抑制而与棉花对枯萎病的抗病性及氟乐灵诱发的诱导抗性有关。
基金supported by the Ministry of Agriculture and Rural Affairs,China(2023ZD04039-01)the National Natural Science Foundation of China(32172008)the Leading Innovative and Entrepreneur Team Introduction Program of Zhejiang,China(2019R01002)。
文摘Pectin is a major constituent of the plant cell wall.Pectate lyase(PEL,EC 4.2.2.2)uses anti-β-elimination chemistry to cleave theα-1,4 glycosidic linkage in the homogalacturonan region of pectin.However,limited information is available on the comprehensive and evolutionary analysis of PELs in the Malvaceae.In this study,we identified 597PEL genes from 10 Malvaceae species.Phylogenetic and motif analyses revealed that these PELs are classified into six subfamilies:Clades I,II,III,IV,Va,and Vb.The two largest subfamilies,Clades I and II,contained 237 and222 PEL members,respectively.The members of Clades Va and Vb only contained four or five motifs,far fewer than the other subfamilies.Gene duplication analysis showed that segmental duplication played a crucial role in the expansion of the PEL gene family in Gossypium species.The PELs from Clades I,IV,Va,and Vb were expressed during the fiber elongation stage,but nearly all PEL genes from Clades II and III showed no expression in any of the investigated fiber developmental stages.We further performed single-gene haplotype association analysis in 2,001G.hirsutum accessions and 229 G.barbadense accessions.Interestingly,14 PELs were significantly associated with fiber length and strength traits in G.barbadense with superior fiber quality,while only eight GhPEL genes were found to be significantly associated with fiber quality traits in G.hirsutum.Our findings provide important information for further evolutionary and functional research on the PEL gene family members and their potential use for fiber quality improvement in cotton.
基金supported by the Special Fund for Agro-scientific Research in the Public Interest in China (201503114)
文摘The soybean cyst nematode, Heterodeara glycines, is a serious pathogen of soybean, and reported to be the host of a wide range of Fabaceae. In the present study, the host specificity and reproductivity of two populations of H. glycines collected from soybean and tobacco were identified and characterized. The comparative identity between β-1,4-endoglucanase, pectate lyase and chorismate mutase of H. glycines parasitizing on soybean and tobacco were 99, 97 and 98%, respectively. The qR T-PCR analysis indicated that the expression of pectate lyase 2 gene was significantly higher in second-stage juveniles of H. glycines Henan population parasitizing on tobacco than that of H. glycines Shanxi population parasitizing on soybean. In addition, the pectic acid content of cell wall was significantly higher(45%) in the roots of tobacco than the roots of soybean. Our results indicate that the changes in transcript parasitism genes may be a result of long-term evolution illustrating how a plant-parasitic nematode adapts to the host environment for optimal infestation and survival.
基金supported by grants from the National Transgenic Science and Technology Program,China(2016ZX08009003-003)the National Key Research and Development Program of China(2016YFD0101100)+1 种基金the Youth Innovation Team Program of Chongqing Academy of Agricultural Sciences,China(NKY-2018QC03)the National Natural Science Foundation of China(31960401)。
文摘Rice panicle apical abortion(PAA)is a detrimental agronomic trait resulting in spikelet number reduction and yield loss.To understand its underlying molecular mechanism,we identified one recessive PAA mutant tutou2 from the offspring of tissue cultures.The mutation locus was finely mapped to a 75-kb interval on the long arm of chromosome 10.Sequence analysis revealed a single nucleotide substitution of A to T at the 941 position of LOC_Os10g31910 in tutou2,resulting in an amino acid change from isoleucine to phenylalanine.Complementation analysis showed that the degenerated panicle phenotype in tutou2 was rescued in the transgenic lines.A phenotype similar to tutou2 can also be obtained by LOC_Os10g31910 knockout in wild-type rice.These results suggested that LOC_Os10 g31910 is the causative locus TUTOU2 responsible for the tutou2 PAA phenotype and probably also the locus of DEL1,previously documented as a leaf senescence gene.The significant phenotypic differences between del1 and tutou2 suggest that the locus DEL1/TUTOU2 plays roles in both leaf and panicle development which were not considered fully in previous studies.
