In higher plants,the shoot apical meristem produces lateral organs in a regular spacing(phyllotaxy)and timing(plastochron).The molecular analysis of mutants associated with phyllotaxy and plastochron would increase ou...In higher plants,the shoot apical meristem produces lateral organs in a regular spacing(phyllotaxy)and timing(plastochron).The molecular analysis of mutants associated with phyllotaxy and plastochron would increase our understanding of the mechanism of shoot architecture formation.In this study,we identified mutant mnd8ynp5 that shows an increased rate of leaf emergence and a larger number of nodes in combination with a dwarfed growth habit from an EMS-treated population of the elite barley cultivar Yangnongpi 5.Using a map-based cloning strategy,the mnd8 gene was narrowed down to a 6.7-kb genomic interval on the long arm of chromosome 5H.Sequence analysis revealed that a C to T single-nucleotide mutation occurred at the first exon(position 953)of HORVU5Hr1G118820,leading to an alanine(Ala)to valine(Val)substitution at the 318th amino acid site.Next,HORVU5Hr1G118820 was defined as the candidate gene of MND8 encoding 514 amino acids and containing two multidrug and toxic compound extrusion(MATE)domains.It is highly homologous to maize Bige1and has a conserved function in the regulation of plant development by controlling the leaf initiation rate.Examination of modern barely varieties showed that Hap-1 was the dominant haplotype and was selected in barley breeding around the world.Collectively,our results indicated that mnd8ynp5 is a novel allele of the HORVU5Hr1G118820 gene that is possibly responsible for the shortened plastochron and many noded dwarf phenotype in barley.展开更多
In wheat plants at the vegetative growth stage, the shoot apical meristem (SAM) produces leaf primordia. When reproductive growth is initiated, the SAM forms an inflorescence meristem (IM) that differentiates a series...In wheat plants at the vegetative growth stage, the shoot apical meristem (SAM) produces leaf primordia. When reproductive growth is initiated, the SAM forms an inflorescence meristem (IM) that differentiates a series of spikelet meristem (SM) as the branch. The SM then produces a series of floret meristem (FM) as the branch. To identify the mechanisms that regulate formation of the reproductive meristems in wheat, we have investigated a leaf initiation mutant, fushi-darake (fdk) which was developed by ion beam mutagenesis. The morphological traits were compared in wild type (WT) and fdk mutant plants grown in the experimental field. WT plants initiated leaves from SAM at regular intervals in spiral phyllotaxy, while fdk plants had 1/2 alternate phyllotaxy with rapid leaf emergence. The fdk plants have increased numbers of nodes and leaves compared with WT plants. The time interval between successive leaf initiation events (plastochron) was measured in plants grown in a growth chamber. The fdk plants clearly show the rapid leaf emergence, indicating a shortened plastochron. Each tiller in fdk plants branches at the upper part of the culm. The fine structure of organ formation in meristems of fdk plants was examined by scanning electron microscopy (SEM). The SEM analysis indicated that fdk plants show transformation of spikelet meristems into vegetative shoot meristems. In conclusion, the fdk mutant has a heterochronic nature, i.e., both reproductive and vegetative programs were simultaneously in operation during the reproductive phase, resulting in a shortened plastochron and transformation of reproductive spikelets into vegetative shoots.展开更多
During vegetative development, higher plants continuously form new leaves in regular spatial and temporal patterns. Mutants with abnormal leaf developmental patterns not only provide a great insight into understanding...During vegetative development, higher plants continuously form new leaves in regular spatial and temporal patterns. Mutants with abnormal leaf developmental patterns not only provide a great insight into understanding the regulatory mechanism of plant architecture, but also enrich the ways to its modification by which crop yield could be improved. Here, we reported the characterization of the rice leafy-head2 （lhd2） mutant that exhibits shortened plastochron, dwarfism, reduced tiller number, and failure of phase transition from vegetative to reproductive growth. Anatomical and histological study revealed that the rapid emergence of leaves in lhd2 was resulted from the rapid initiation of leaf primordia whereas the reduced tiller number was a consequence of the suppression of the tiller bud outgrowth. The molecular and genetic analysis showed that LHD2 encodes a putative RNA binding protein with 67% similarity to maize TEl. Comparison of genome-scale expression profiles between wild-type and lhd2 plants suggested that LHD2 may regulate rice shoot development through KNOXand hormone-related genes. The similar phenotypes caused by LHD2 mutation and the conserved expression pattern of LHD2 indicated a conserved mechanism in controlling the temporal leaf initiation in grass.展开更多
基金funded by the Open Project Program of State Key Laboratory of Barley and Yak Germplasm Resources and Genetic Improvement,China(XZNKY2021-C-014-K01)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(19KJA560005)+1 种基金the China Agriculture Research System(CARS-05)a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions,China。
文摘In higher plants,the shoot apical meristem produces lateral organs in a regular spacing(phyllotaxy)and timing(plastochron).The molecular analysis of mutants associated with phyllotaxy and plastochron would increase our understanding of the mechanism of shoot architecture formation.In this study,we identified mutant mnd8ynp5 that shows an increased rate of leaf emergence and a larger number of nodes in combination with a dwarfed growth habit from an EMS-treated population of the elite barley cultivar Yangnongpi 5.Using a map-based cloning strategy,the mnd8 gene was narrowed down to a 6.7-kb genomic interval on the long arm of chromosome 5H.Sequence analysis revealed that a C to T single-nucleotide mutation occurred at the first exon(position 953)of HORVU5Hr1G118820,leading to an alanine(Ala)to valine(Val)substitution at the 318th amino acid site.Next,HORVU5Hr1G118820 was defined as the candidate gene of MND8 encoding 514 amino acids and containing two multidrug and toxic compound extrusion(MATE)domains.It is highly homologous to maize Bige1and has a conserved function in the regulation of plant development by controlling the leaf initiation rate.Examination of modern barely varieties showed that Hap-1 was the dominant haplotype and was selected in barley breeding around the world.Collectively,our results indicated that mnd8ynp5 is a novel allele of the HORVU5Hr1G118820 gene that is possibly responsible for the shortened plastochron and many noded dwarf phenotype in barley.
文摘In wheat plants at the vegetative growth stage, the shoot apical meristem (SAM) produces leaf primordia. When reproductive growth is initiated, the SAM forms an inflorescence meristem (IM) that differentiates a series of spikelet meristem (SM) as the branch. The SM then produces a series of floret meristem (FM) as the branch. To identify the mechanisms that regulate formation of the reproductive meristems in wheat, we have investigated a leaf initiation mutant, fushi-darake (fdk) which was developed by ion beam mutagenesis. The morphological traits were compared in wild type (WT) and fdk mutant plants grown in the experimental field. WT plants initiated leaves from SAM at regular intervals in spiral phyllotaxy, while fdk plants had 1/2 alternate phyllotaxy with rapid leaf emergence. The fdk plants have increased numbers of nodes and leaves compared with WT plants. The time interval between successive leaf initiation events (plastochron) was measured in plants grown in a growth chamber. The fdk plants clearly show the rapid leaf emergence, indicating a shortened plastochron. Each tiller in fdk plants branches at the upper part of the culm. The fine structure of organ formation in meristems of fdk plants was examined by scanning electron microscopy (SEM). The SEM analysis indicated that fdk plants show transformation of spikelet meristems into vegetative shoot meristems. In conclusion, the fdk mutant has a heterochronic nature, i.e., both reproductive and vegetative programs were simultaneously in operation during the reproductive phase, resulting in a shortened plastochron and transformation of reproductive spikelets into vegetative shoots.
文摘During vegetative development, higher plants continuously form new leaves in regular spatial and temporal patterns. Mutants with abnormal leaf developmental patterns not only provide a great insight into understanding the regulatory mechanism of plant architecture, but also enrich the ways to its modification by which crop yield could be improved. Here, we reported the characterization of the rice leafy-head2 （lhd2） mutant that exhibits shortened plastochron, dwarfism, reduced tiller number, and failure of phase transition from vegetative to reproductive growth. Anatomical and histological study revealed that the rapid emergence of leaves in lhd2 was resulted from the rapid initiation of leaf primordia whereas the reduced tiller number was a consequence of the suppression of the tiller bud outgrowth. The molecular and genetic analysis showed that LHD2 encodes a putative RNA binding protein with 67% similarity to maize TEl. Comparison of genome-scale expression profiles between wild-type and lhd2 plants suggested that LHD2 may regulate rice shoot development through KNOXand hormone-related genes. The similar phenotypes caused by LHD2 mutation and the conserved expression pattern of LHD2 indicated a conserved mechanism in controlling the temporal leaf initiation in grass.
