Sexual reproduction in plants is the main pathway for creating new genetic combinations in modern agriculture.In heterozygous plants,after the identification of a plant with desired traits,vegetative propagation(cloni...Sexual reproduction in plants is the main pathway for creating new genetic combinations in modern agriculture.In heterozygous plants,after the identification of a plant with desired traits,vegetative propagation(cloning)is the primary path to create genetically uniform plants.Another natural plant mechanism that creates genetically uniform plants(clones)is apomixis.In fruit crops like citrus and mango,sporophytic apomixis results in polyembryony,where seeds contain multiple embryos,one of which is sexually originated and the others are vegetative clones of the parent mother tree.Utilizing the mango genome and genetic analysis of a diverse germplasm collection,we identified MiRWP as the gene that causes polyembryony in mango.There is a strong correlation between a specific insertion in the gene’s promoter region and altered expression in flowers and developing fruitlets,inducing multiple embryos.The MiRWP gene is an ortholog of CitRWP that causes polyembryony in citrus.Based on the data,we speculate that promoter insertion events,which occurred independently in citrus and mango,induced nucellar embryogenesis.The results suggest convergent evolution of polyembryony in the two species.Further work is required to demonstrate the utility of these genes(mango and citrus)in other biological systems as a tool for the clonal production of other crops.展开更多
Hyoscyamine, anisodamine and scopolamine are tropane alkaloids present in some Solanaceae species and used in modern medicine. L-Hyoscyamine is hydroxylated to 6</span><i><span style="font-family:V...Hyoscyamine, anisodamine and scopolamine are tropane alkaloids present in some Solanaceae species and used in modern medicine. L-Hyoscyamine is hydroxylated to 6</span><i><span style="font-family:Verdana;">β</span></i><span style="font-family:Verdana;">-hydroxyhyoscyamine (anisodamine) and then epoxidated to scopolamine by the dual action of hyoscyamine 6</span><i><span style="font-family:Verdana;">β</span></i><span style="font-family:Verdana;">-hydroxylase (H6H), a 2-o</span><span><span style="font-family:Verdana;">xoglutarate dependent dioxygenase. A natural mutation in the Gly-220 residue to Cys was previously shown to be associated with the loss of function of H6H in </span><i><span style="font-family:Verdana;">Mandragora</span></i> <i><span style="font-family:Verdana;">officinarum</span></i><span style="font-family:Verdana;">, preventing the accumulation of anisodamin</span></span><span style="font-family:Verdana;">e and scopolamine in these plants. We show here that a deliberate Gly220Cys mutation in the </span><i><span style="font-family:Verdana;">Datura innoxia</span></i><span style="font-family:Verdana;"> DiH6H protein caused a loss of both its enzymatic abilities and rendered it unable to hydroxylate L-hyoscyamine into anisodamine and to epoxidate anisodamine into scopolamine. By using protein modeling based on an available crystal structure of H6H from </span><i><span style="font-family:Verdana;">Datura metel</span></i><span style="font-family:Verdana;">, we show how the Cys220 residue causes a steric interference in the active site cavity impairing the interaction of both substrates, hyoscyamine and anisodamine with the active site of the protein</span></span><span style="font-family:Verdana;">.</span><span style="font-family:Verdana;"> We also address the enantiomeric preference of DiH6H based on molecular modeling.展开更多
Carotenoids,such asβ-carotene,accumulate in chromoplasts of various fleshy fruits,awarding them with colors,aromas,and nutrients.The Orange(CmOr)gene controlsβ-carotene accumulation in melon fruit by posttranslation...Carotenoids,such asβ-carotene,accumulate in chromoplasts of various fleshy fruits,awarding them with colors,aromas,and nutrients.The Orange(CmOr)gene controlsβ-carotene accumulation in melon fruit by posttranslationally enhancing carotenogenesis and repressingβ-carotene turnover in chromoplasts.Carotenoid isomerase(CRTISO)isomerizes yellow prolycopene into red lycopene,a prerequisite for further metabolism intoβ-carotene.We comparatively analyzed the developing fruit transcriptomes of orange-colored melon and its two isogenic EMS-induced mutants,low-β(Cmor)and yofi(Cmcrtiso).The Cmor mutation in low-βcaused a major transcriptomic change in the mature fruit.In contrast,the Cmcrtiso mutation in yofi significantly changed the transcriptome only in early fruit developmental stages.These findings indicate that melon fruit transcriptome is primarily altered by changes in carotenoid metabolic flux and plastid conversion,but minimally by carotenoid composition in the ripe fruit.Clustering of the differentially expressed genes into functional groups revealed an association between fruit carotenoid metabolic flux with the maintenance of the photosynthetic apparatus in fruit chloroplasts.Moreover,large numbers of thylakoid localized photosynthetic genes were differentially expressed in low-β.CmOR family proteins were found to physically interact with light-harvesting chlorophyll a–b binding proteins,suggesting a new role of CmOR for chloroplast maintenance in melon fruit.This study brings more insights into the cellular and metabolic processes associated with fruit carotenoid accumulation in melon fruit and reveals a new maintenance mechanism of the photosynthetic apparatus for plastid development.展开更多
The cwp(cuticular water permeability)gene controls the development of cuticular microfissuring and subsequent fruit dehydration in tomato.The gene underwent silencing in the evolution of the fleshy cultivated tomato b...The cwp(cuticular water permeability)gene controls the development of cuticular microfissuring and subsequent fruit dehydration in tomato.The gene underwent silencing in the evolution of the fleshy cultivated tomato but is expressed in the primitive wild tomato relatives.The introgression of the expressed allele from the wild S.habrochaites(cwph)into the cultivated tomato(Solanum lycopersicum)leads to the phenotype of fruit water loss during and following ripening.In this report,we show that low temperature impacts on the severity of the cuticular microfissure phenotype via a combination of effects on both expression and alternative splicing of cwph.The cwp gene,comprising four exons and three introns,undergoes post-transcriptional alternative splicing processes,leading to seven alternative transcripts that differ in reading-frame lengths.Transgenic plants expressing each of the alternative transcripts identified the longest reading frame(VAR1)as the functional splice variant.Low temperature led to a strong upregulation of cwph expression,compounded by an increase in the relative proportion of the functional VAR1 transcript,leading to increased severity of microfissuring of the cuticle.In summary,we demonstrate the molecular mechanism behind the horticultural phenomenon of the low-temperature effect on cuticular microfissures in the dehydrating tomato.展开更多
基金The research was supported by Research Grant No.IS-5106-18R from BARD,The United States-Israel Binational Agricultural Research and Development Fund(granted to A.S.,D.N.K.,Y.C.,and R.O.)by grants No.203-0859(granted to A.S.and R.O.)No.203-0110(granted to Y.C.)from the Chief Scientist of the Israeli Ministry of Agriculture.D.N.K.was supported by a grant from the USDA National Institute of Food and Agriculture(USDA-NIFA 2018-51181-28375).
文摘Sexual reproduction in plants is the main pathway for creating new genetic combinations in modern agriculture.In heterozygous plants,after the identification of a plant with desired traits,vegetative propagation(cloning)is the primary path to create genetically uniform plants.Another natural plant mechanism that creates genetically uniform plants(clones)is apomixis.In fruit crops like citrus and mango,sporophytic apomixis results in polyembryony,where seeds contain multiple embryos,one of which is sexually originated and the others are vegetative clones of the parent mother tree.Utilizing the mango genome and genetic analysis of a diverse germplasm collection,we identified MiRWP as the gene that causes polyembryony in mango.There is a strong correlation between a specific insertion in the gene’s promoter region and altered expression in flowers and developing fruitlets,inducing multiple embryos.The MiRWP gene is an ortholog of CitRWP that causes polyembryony in citrus.Based on the data,we speculate that promoter insertion events,which occurred independently in citrus and mango,induced nucellar embryogenesis.The results suggest convergent evolution of polyembryony in the two species.Further work is required to demonstrate the utility of these genes(mango and citrus)in other biological systems as a tool for the clonal production of other crops.
文摘Hyoscyamine, anisodamine and scopolamine are tropane alkaloids present in some Solanaceae species and used in modern medicine. L-Hyoscyamine is hydroxylated to 6</span><i><span style="font-family:Verdana;">β</span></i><span style="font-family:Verdana;">-hydroxyhyoscyamine (anisodamine) and then epoxidated to scopolamine by the dual action of hyoscyamine 6</span><i><span style="font-family:Verdana;">β</span></i><span style="font-family:Verdana;">-hydroxylase (H6H), a 2-o</span><span><span style="font-family:Verdana;">xoglutarate dependent dioxygenase. A natural mutation in the Gly-220 residue to Cys was previously shown to be associated with the loss of function of H6H in </span><i><span style="font-family:Verdana;">Mandragora</span></i> <i><span style="font-family:Verdana;">officinarum</span></i><span style="font-family:Verdana;">, preventing the accumulation of anisodamin</span></span><span style="font-family:Verdana;">e and scopolamine in these plants. We show here that a deliberate Gly220Cys mutation in the </span><i><span style="font-family:Verdana;">Datura innoxia</span></i><span style="font-family:Verdana;"> DiH6H protein caused a loss of both its enzymatic abilities and rendered it unable to hydroxylate L-hyoscyamine into anisodamine and to epoxidate anisodamine into scopolamine. By using protein modeling based on an available crystal structure of H6H from </span><i><span style="font-family:Verdana;">Datura metel</span></i><span style="font-family:Verdana;">, we show how the Cys220 residue causes a steric interference in the active site cavity impairing the interaction of both substrates, hyoscyamine and anisodamine with the active site of the protein</span></span><span style="font-family:Verdana;">.</span><span style="font-family:Verdana;"> We also address the enantiomeric preference of DiH6H based on molecular modeling.
基金the United States-Israel Binational Agricultural Research and Development Fund(grant no.US-4918-16CR)the Agriculture and Food Research Initiative competitive award(grant no.2019-67013-29162)from the USDA National Institute of Food and Agriculture,and the USDA-ARS fund.
文摘Carotenoids,such asβ-carotene,accumulate in chromoplasts of various fleshy fruits,awarding them with colors,aromas,and nutrients.The Orange(CmOr)gene controlsβ-carotene accumulation in melon fruit by posttranslationally enhancing carotenogenesis and repressingβ-carotene turnover in chromoplasts.Carotenoid isomerase(CRTISO)isomerizes yellow prolycopene into red lycopene,a prerequisite for further metabolism intoβ-carotene.We comparatively analyzed the developing fruit transcriptomes of orange-colored melon and its two isogenic EMS-induced mutants,low-β(Cmor)and yofi(Cmcrtiso).The Cmor mutation in low-βcaused a major transcriptomic change in the mature fruit.In contrast,the Cmcrtiso mutation in yofi significantly changed the transcriptome only in early fruit developmental stages.These findings indicate that melon fruit transcriptome is primarily altered by changes in carotenoid metabolic flux and plastid conversion,but minimally by carotenoid composition in the ripe fruit.Clustering of the differentially expressed genes into functional groups revealed an association between fruit carotenoid metabolic flux with the maintenance of the photosynthetic apparatus in fruit chloroplasts.Moreover,large numbers of thylakoid localized photosynthetic genes were differentially expressed in low-β.CmOR family proteins were found to physically interact with light-harvesting chlorophyll a–b binding proteins,suggesting a new role of CmOR for chloroplast maintenance in melon fruit.This study brings more insights into the cellular and metabolic processes associated with fruit carotenoid accumulation in melon fruit and reveals a new maintenance mechanism of the photosynthetic apparatus for plastid development.
文摘The cwp(cuticular water permeability)gene controls the development of cuticular microfissuring and subsequent fruit dehydration in tomato.The gene underwent silencing in the evolution of the fleshy cultivated tomato but is expressed in the primitive wild tomato relatives.The introgression of the expressed allele from the wild S.habrochaites(cwph)into the cultivated tomato(Solanum lycopersicum)leads to the phenotype of fruit water loss during and following ripening.In this report,we show that low temperature impacts on the severity of the cuticular microfissure phenotype via a combination of effects on both expression and alternative splicing of cwph.The cwp gene,comprising four exons and three introns,undergoes post-transcriptional alternative splicing processes,leading to seven alternative transcripts that differ in reading-frame lengths.Transgenic plants expressing each of the alternative transcripts identified the longest reading frame(VAR1)as the functional splice variant.Low temperature led to a strong upregulation of cwph expression,compounded by an increase in the relative proportion of the functional VAR1 transcript,leading to increased severity of microfissuring of the cuticle.In summary,we demonstrate the molecular mechanism behind the horticultural phenomenon of the low-temperature effect on cuticular microfissures in the dehydrating tomato.