The chestnuts genus(Castanea spp.)is comprised of economically important trees native to the Northern hemisphere that are used as food and hardwood timber.Here,a very efficient method for micropropagation of European&...The chestnuts genus(Castanea spp.)is comprised of economically important trees native to the Northern hemisphere that are used as food and hardwood timber.Here,a very efficient method for micropropagation of European×Japanese chestnut hybrids(Castanea sativa×C.crenata)is described.Woody Plant Medium was used as the basal medium.In vitro shoots of four rootstock cultivars were micropropagated without shoot-tip necrosis on multiplication medium containing 5.7 or 11.4μmol·L^(−1)zeatin riboside,and were rooted on rooting medium containing 2.46μmol·L^(−1)indolebutyric acid.Monthly shootmultiplication rates for each cultivarwere 2–5 folds.In vitro rooting percentages for four cultivars were 87%for‘Maraval’,67%for‘Marigoule’,93%for‘Marsol’,and 97%for‘Précoce Migoule’.Within a 5 week period,80%–95%of rooted shoots were successfully acclimated under high humidity conditions after they were planted in either soil or rockwool.展开更多
The molecular mechanism underlying dormancy release and the induction of flowering remains poorly understood in woody plants.Mu-legacy is a valuable blueberry mutant,in which a transgene insertion caused increased exp...The molecular mechanism underlying dormancy release and the induction of flowering remains poorly understood in woody plants.Mu-legacy is a valuable blueberry mutant,in which a transgene insertion caused increased expression of a RESPONSE REGULATOR 2-like gene(VcRR2).Mu-legacy plants,compared with nontransgenic‘Legacy’plants,show dwarfing,promotion of flower bud formation,and can flower under nonchilling conditions.We conducted transcriptomic comparisons in leaves,chilled and nonchilled flowering buds,and late-pink buds,and analyzed a total of 41 metabolites of six groups of hormones in leaf tissues of both Mu-legacy and‘Legacy’plants.These analyses uncovered that increased VcRR2 expression promotes the expression of a homolog of Arabidopsis thaliana ENTCOPALYL DIPHOSPHATE SYNTHETASE 1(VcGA1),which induces new homeostasis of hormones,including increased gibberellin 4(GA4)levels in Mu-legacy leaves.Consequently,increased expression of VcRR2 and VcGA1,which function in cytokinin responses and gibberellin synthesis,respectively,initiated the reduction in plant height and the enhancement of flower bud formation of the Mu-legacy plants through interactions of multiple approaches.In nonchilled flower buds,29 differentially expressed transcripts of 17 genes of five groups of hormones were identified in transcriptome comparisons between Mu-legacy and‘Legacy’plants,of which 22 were chilling responsive.Thus,these analyses suggest that increased expression of VcRR2 was collectively responsible for promoting flower bud formation in highbush blueberry under nonchilling conditions.We report here for the first time the importance of VcRR2 to induce a suite of downstream hormones that promote flowering in woody plants.展开更多
基金the Michigan State University-Ernie and Mabel Rogers Endowment.
文摘The chestnuts genus(Castanea spp.)is comprised of economically important trees native to the Northern hemisphere that are used as food and hardwood timber.Here,a very efficient method for micropropagation of European×Japanese chestnut hybrids(Castanea sativa×C.crenata)is described.Woody Plant Medium was used as the basal medium.In vitro shoots of four rootstock cultivars were micropropagated without shoot-tip necrosis on multiplication medium containing 5.7 or 11.4μmol·L^(−1)zeatin riboside,and were rooted on rooting medium containing 2.46μmol·L^(−1)indolebutyric acid.Monthly shootmultiplication rates for each cultivarwere 2–5 folds.In vitro rooting percentages for four cultivars were 87%for‘Maraval’,67%for‘Marigoule’,93%for‘Marsol’,and 97%for‘Précoce Migoule’.Within a 5 week period,80%–95%of rooted shoots were successfully acclimated under high humidity conditions after they were planted in either soil or rockwool.
基金supported by AgBioResearch of Michigan State University(http://www.canr.msu.edu/research/agbioresearch/)and USDA-NIFA AFRI 1015241 to P.P.E.and G.S.
文摘The molecular mechanism underlying dormancy release and the induction of flowering remains poorly understood in woody plants.Mu-legacy is a valuable blueberry mutant,in which a transgene insertion caused increased expression of a RESPONSE REGULATOR 2-like gene(VcRR2).Mu-legacy plants,compared with nontransgenic‘Legacy’plants,show dwarfing,promotion of flower bud formation,and can flower under nonchilling conditions.We conducted transcriptomic comparisons in leaves,chilled and nonchilled flowering buds,and late-pink buds,and analyzed a total of 41 metabolites of six groups of hormones in leaf tissues of both Mu-legacy and‘Legacy’plants.These analyses uncovered that increased VcRR2 expression promotes the expression of a homolog of Arabidopsis thaliana ENTCOPALYL DIPHOSPHATE SYNTHETASE 1(VcGA1),which induces new homeostasis of hormones,including increased gibberellin 4(GA4)levels in Mu-legacy leaves.Consequently,increased expression of VcRR2 and VcGA1,which function in cytokinin responses and gibberellin synthesis,respectively,initiated the reduction in plant height and the enhancement of flower bud formation of the Mu-legacy plants through interactions of multiple approaches.In nonchilled flower buds,29 differentially expressed transcripts of 17 genes of five groups of hormones were identified in transcriptome comparisons between Mu-legacy and‘Legacy’plants,of which 22 were chilling responsive.Thus,these analyses suggest that increased expression of VcRR2 was collectively responsible for promoting flower bud formation in highbush blueberry under nonchilling conditions.We report here for the first time the importance of VcRR2 to induce a suite of downstream hormones that promote flowering in woody plants.
