Lilium is an ornamental bulb with a long juvenile stage,making its cultivation under natural conditions lengthy and costly.SQUAMOSA promoterbinding protein-like(SPL)transcription factors are related to plant growth an...Lilium is an ornamental bulb with a long juvenile stage,making its cultivation under natural conditions lengthy and costly.SQUAMOSA promoterbinding protein-like(SPL)transcription factors are related to plant growth and development,including phase transition.However,their role in phase transition in Lilium is not known.To explore the molecular mechanisms associated with the phase transition in Lilium,bulbs of Lilium Oriental Trumpet'Robina'were treated with lowered temperature to induce phase transition,and the small RNA and degradome were sequenced.A total of 161 miRNAs were identified as targets.Twenty-nine known miRNAs were differentially expressed,including 16 upregulated miRNAs and 13 down-regulated miRNAs.Lbr-miR156a was significantly down-regulated,and the target genes of Lbr-miR156a were identified as LbrSPL3 and LbrSPL16.Phylogenetic analysis showed that LbrSPL3 and LbrSPL16 had high homology with other plant SPLs.Subcellular localization and transcriptional activation experiments confirmed that LbrSPL3 and LbrSPL16 were mainly located in the nucleus and had transcriptional activity.The in situ hybridization results showed that the expression of LbrSPL3 and LbrSPL16 was increased following low-temperature treatment.Functional verification experiments of Arabidopsis transgenic plants showed that the overexpression of LbrSPL3 and LbrSPL16 could promote plant phase change,while the overexpression of Lbr-miR156a could inhibit this process.These results help elucidate the mechanism of phase transition regulation in Lilium and provide a reference for breeding research in other bulbous flowers.展开更多
The pollination methods and embryo rescue techniques of hybridization between I.ilium Oriental hybrids were studied in this paper. The results showed that ： （ 1 ） in the combination of ＇ Justina＇ x ＇ Shala＇, po...The pollination methods and embryo rescue techniques of hybridization between I.ilium Oriental hybrids were studied in this paper. The results showed that ： （ 1 ） in the combination of ＇ Justina＇ x ＇ Shala＇, pollen tubes were observed to grow downward in styles and target to ovules in ovaries when normal sti^na 13o1- lination method was used; pollen tubes were found to grow directionless to a different degree at stylar cuts and in ovaries when cut-style pollination method was used; the longer the styles were left, the more pollen tubes toward to ovules were observed and more plump seeds were produced; the maximum plump seeds were obtained via normal stigma pollination. （2） Hybridization experiments were performed for the 56 combinations of Lilium Oriental hybrids with normal stigma pollina- tion, and one combination generated no plump ovule and three combinations generated fewer than 10 plump ovules while the other 52 combinations generated plenty of plump ovules, which preliminarily indicated that normal stigma pollination method could be used as an universal pollination technique for hybridization between Lilium Oriental hybrids. The experiment results of different embryo rescue techniques showed that using cut-ovule inoculation about 70 d after pollination had a fas- ter germination speed and a higher germination rate of hybrid embryo than normal ovule inoculation, and embryo rescue efficiency of the former method was obviously higher than ＂embryo isolated inoculation＂ on 40 d after pollination. The research suggested that ＂cut-ovule inoculation＂ about 70 d after pollination could be regarded as an universal embryo rescue technique for hybridization between Lilium Oriental hybrids.展开更多
基金supported by the Beijing Natural Science Fund-Municipal Education Commission Jointly Funded Projects(grant No.KZ201810020029)Beijing Excellent Training Project to WG(grant No.68).
文摘Lilium is an ornamental bulb with a long juvenile stage,making its cultivation under natural conditions lengthy and costly.SQUAMOSA promoterbinding protein-like(SPL)transcription factors are related to plant growth and development,including phase transition.However,their role in phase transition in Lilium is not known.To explore the molecular mechanisms associated with the phase transition in Lilium,bulbs of Lilium Oriental Trumpet'Robina'were treated with lowered temperature to induce phase transition,and the small RNA and degradome were sequenced.A total of 161 miRNAs were identified as targets.Twenty-nine known miRNAs were differentially expressed,including 16 upregulated miRNAs and 13 down-regulated miRNAs.Lbr-miR156a was significantly down-regulated,and the target genes of Lbr-miR156a were identified as LbrSPL3 and LbrSPL16.Phylogenetic analysis showed that LbrSPL3 and LbrSPL16 had high homology with other plant SPLs.Subcellular localization and transcriptional activation experiments confirmed that LbrSPL3 and LbrSPL16 were mainly located in the nucleus and had transcriptional activity.The in situ hybridization results showed that the expression of LbrSPL3 and LbrSPL16 was increased following low-temperature treatment.Functional verification experiments of Arabidopsis transgenic plants showed that the overexpression of LbrSPL3 and LbrSPL16 could promote plant phase change,while the overexpression of Lbr-miR156a could inhibit this process.These results help elucidate the mechanism of phase transition regulation in Lilium and provide a reference for breeding research in other bulbous flowers.
基金Supported by Natural Science Foundation of Beijing(6122004)Project of Science and Technology Innovation of Beijing(PXM2013-014207-000051,PXM2014-014207-000018)+2 种基金Science and Technology Promotion Project of Beijing(PXM2013-014207-000079,PXM2014-014207-000081)Project of Beijing Laboratory of Urban and Rural Ecological Environment(PXM2015-014207-000014)Project of Construction of Innovative Teams and TeacherCareer Development for Universities and Colleges under Beijing Municipality(IDHT20150503)
文摘The pollination methods and embryo rescue techniques of hybridization between I.ilium Oriental hybrids were studied in this paper. The results showed that ： （ 1 ） in the combination of ＇ Justina＇ x ＇ Shala＇, pollen tubes were observed to grow downward in styles and target to ovules in ovaries when normal sti^na 13o1- lination method was used; pollen tubes were found to grow directionless to a different degree at stylar cuts and in ovaries when cut-style pollination method was used; the longer the styles were left, the more pollen tubes toward to ovules were observed and more plump seeds were produced; the maximum plump seeds were obtained via normal stigma pollination. （2） Hybridization experiments were performed for the 56 combinations of Lilium Oriental hybrids with normal stigma pollina- tion, and one combination generated no plump ovule and three combinations generated fewer than 10 plump ovules while the other 52 combinations generated plenty of plump ovules, which preliminarily indicated that normal stigma pollination method could be used as an universal pollination technique for hybridization between Lilium Oriental hybrids. The experiment results of different embryo rescue techniques showed that using cut-ovule inoculation about 70 d after pollination had a fas- ter germination speed and a higher germination rate of hybrid embryo than normal ovule inoculation, and embryo rescue efficiency of the former method was obviously higher than ＂embryo isolated inoculation＂ on 40 d after pollination. The research suggested that ＂cut-ovule inoculation＂ about 70 d after pollination could be regarded as an universal embryo rescue technique for hybridization between Lilium Oriental hybrids.
