[Purpose] The paper is to discuss the high-efficient breeding technology platform of dwarf male-sterile wheat.[Method] Conclusion was made upon the development of the creation and application of dwarf male-sterile whe...[Purpose] The paper is to discuss the high-efficient breeding technology platform of dwarf male-sterile wheat.[Method] Conclusion was made upon the development of the creation and application of dwarf male-sterile wheat,and the conception of introducing haploid breeding technology into the technological system of high-efficient breeding of dwarf male-sterile wheat was proposed.[Result] Dwarf male-sterile wheat not only retains the properties of total male abortion of Taigu Genetic Sterile Wheat,steady sterility,and high hybrid rate after open pollination,but also has the characteristic of high dwarfing ability of Aibian No.1,becoming a comparatively ideal population modification means.At present,the application of dwarf male-sterile wheat mainly includes germplasm resources platform of population modification by using dwarf male-sterile wheat,technology platform of constructing new high-efficient breeding system by using dwarf male-sterile wheat,and production platform of using dwarf male-sterile wheat to breed new varieties.Through the introduction of haploid breeding into the already established wheat high-efficient breeding system,a new system of high-efficient biological breeding technology of dwarf male-sterile wheat was constructed theoretically.[Conclusion] The study provides references to the further study and application of dwarf male-sterile wheat.展开更多
Understanding the effects of wheat dwarfing genes on the coleoptile length and plant height is crucial for the proper utilization of dwarfing genes in the improvement of wheat yield. Molecular marker analysis combined...Understanding the effects of wheat dwarfing genes on the coleoptile length and plant height is crucial for the proper utilization of dwarfing genes in the improvement of wheat yield. Molecular marker analysis combined with pedigree information were used to classify wheat cultivars widely planted in major wheat growing regions in China into different categories based on the dwarfing genes they carried. The effects of the dwarfing genes with different sensitivity to gibberellins （GA3） on the coleoptile length and plant height were analyzed. Screening of 129 cultivars by molecular marker analysis revealed that 58 genotypes of wheat contained the dwarfing gene Rht-B1b, 24 genotypes of wheat contained Rht-D1b gene and 73 genotypes of wheat possessed Rht8 gene. In addition, among these 129 cultivars, 35 genotypes of wheat cultivars contained both Rht-B1b and Rht8 genes and 16 genotypes of wheat cultivars contained both Rht-D1b and Rht8 genes. Wheat cultivars with the dwarfing genes Rht-B1b or Rht-D1b were insensitive to GA3, while the cultivars with the dwarfing gene Rht8 were sensitive to GA3. Most of the wheat genotypes containing combination of Rht8 gene with either Rht-B1b or Rht-D1b gene were insensitive to GA3. The plant height was reduced by 24.6, 30.4, 28.2, and 32.2%, respectively, for the wheat cultivars containing Rht-B1b, Rht-D1b, Rht-B1b ＋ Rht8, and Rht-D1b ＋ Rht8 genes. The plant height was reduced by 14.3% for the wheat cultivar containing GA3-sensitive gene Rht8. The coleoptile length was shortened by 25.4, 31.3, 28.4 and 31.3%, respectively, in the wheat cultivars containing Rht-B1b, Rht-D1b, Rht-B1b ＋Rht8 and Rht-D1b ＋ Rht8 genes, while the coleoptile length was shortened only by 6.2% for the wheat cultivar containing Rht8 gene. We conclude that GA3-insensitive dwarfing genes （Rht-B1b and Rht-D1b） are not suitable for the wheat improvement in dryland because these two genes have effect on reducing both plant height and coleoptile length. In contrast, GA3- sensitive dwarfing gene （Rht8） is a relatively ideal candidate for the wheat improvement since it significantly reduces the plant height of wheat, but has less effect on the coleoptile length.展开更多
Plant height and fertility are two important traits of wheat (Triticum aestivum L.), whose mutants are ideal materials for studies on molecular mechanisms of stem and lforal organ development. In this study, we identi...Plant height and fertility are two important traits of wheat (Triticum aestivum L.), whose mutants are ideal materials for studies on molecular mechanisms of stem and lforal organ development. In this study, we identiifed a dwarf, multi-pistil and male sterile (dms hereafter) wheat mutant from Zhoumai 18. Simple sequence repeat (SSR) marker assay with 181 primer pairs showed that only one locus of GWM148-2B was divergent between Zhoumai 18 and dms. There were three typical phenotypes in the progeny of dms, tal (T;ca. 0.8 m), semi-dwarf (M;ca. 0.6 m) and dwarf (D;under 0.3 m) plants. Morphological investigation indicated that the internode length of M was shortened by about 20–50 mm each;the internode number of D was 2 less than that of T and Zhoumai 18, and its internode length was shorter also. The pol en vigor and hybridization test demonstrated that dms mutant was male sterility. Segregated phenotypes in progeny of M suggested that the multi-pistils and sterility were control ed by one recessive gene locus which was designated as dms temporarily, and the plant height was control ed by a semi-dominant gene locus Dms. Therefore, progeny individuals of the dms had three genotypes, DmsDms for tal plants, Dmsdms for semi-dwarf plants and dmsdms for dwarf plants. The mutant progenies were individual y selected and propagated for more than 6 generations, thus a set of near isogenic lines of T, M and D for dms were developed. This study provides a set germplasms for studies on molecular mechanisms of wheat stem and spike development.展开更多
Dwarfing breeding of wheat in the world is confined to the exploitation of recessive dwarfing sources. None of the dominant dwarfing sources discovered in common wheat (Triticum aestivum L.) has found wide exploitatio...Dwarfing breeding of wheat in the world is confined to the exploitation of recessive dwarfing sources. None of the dominant dwarfing sources discovered in common wheat (Triticum aestivum L.) has found wide exploitation in wheat breeding due to the extreme dwarfness of their plants (2055 cm). We found in our work that some stable mutant lines with their plant height enhanced to different extents could be obtained in large populations derived from the stock seeds of the dominant dwarfing sources Aibian1 carrying Rht10 on 4DS and being 2055 cm tall and Aisu2 carrying Rht3 on 4BS and being 55 cm tall, or from their descendants of induced mutation treatments, or from the segregating descendants of their crosses with mid- or tall-statured genotypes. Subsequently, we studied these mutation-derived lines differing in plant height with near isogenic lines and observed that the character of their enhanced plant height bred true, each carrying a semi-dominant dwarfing gene for a definite height and that as the plant height of the mutation-derived lines increased, the yield-contributing characters of their near isogenic lines were significantly improved. When test crosses with marker genes and physiological and biochemical genetic marker tests were performed to re-localize the semi-dominant dwarfing genes carried by the mutation-derived lines, it was confirmed that they shared common loci with Rht10 and Rht3 and that they were all mutation-derived multiple alleles. It is thus speculated that dominant dwarfing genes are of 'multi-allelic polymorphism'. In other words, dominant dwarfing genes, which are ultra-dwarfing, are liable to develop by mutation into a group of multiple alleles with plant height enhanced to different extents and some may have a height close to the ideal plant height for wheat breeding. Therefore, these results offer a fundamentally new approach for the exploitation of dominant dwarfing sources in wheat breeding.展开更多
The value of different dwarfing genes in winter wheat breeding was studied using 6 near-isogenic lines carrying different Rht dwarfing genes over three years experiment.Results showed that both the Rht1 and Rht2 semi-...The value of different dwarfing genes in winter wheat breeding was studied using 6 near-isogenic lines carrying different Rht dwarfing genes over three years experiment.Results showed that both the Rht1 and Rht2 semi-dwarfing genes had significantlypositive effects on kernel number and grain weight per spike, and had significantlynegative effects on 1000-grain weight comparing to the tall line(rht) and the Rht3 line.The Rht3 dwarfing gene had a significantly negative effect on kernel number per spike,and had positive effect on 1000-grain weight. The combination of the Rht2 and Rht3 geneshowed significantly negative effect on yield components. All of these 5 dwarfing orsemidwarfing genotypes mentioned above had a significantly negative effect on plantheight and no significant effect on the area of flag leaf, spikelets per spike and spikelength.展开更多
Wheat dwarf bunt, caused by Tilletia controversa Kühn （TCK）, is an important quarantine wheat disease throughout the world. Based on published research results of the biology and the epidemiology of the disease...Wheat dwarf bunt, caused by Tilletia controversa Kühn （TCK）, is an important quarantine wheat disease throughout the world. Based on published research results of the biology and the epidemiology of the disease, the main factors including temperature, humidity, snow cover, and their parameters relating to teliospore germination, infection and epidemics of TCK were determined. The geophytopathological models for the risk analysis of wheat dwarf bunt establishment were modified. Fifty-year meteorologic data from about 500 weather stations in China were used to calculate the probabilities of TCK establishment in different geographic sites with the models. The map that displays the establishment risk of TCK in winter wheat growing regions in China was generated by using geographical information system （GIS）. The zones showing high, moderate, low, and very low, including no risk, of TCK establishment accounted for 27.33, 27.69, 38.12, and 6.86% of total winter wheat growing areas in China, respectively. These results will provide useful information to formulate quarantine regulations and wheat importation policy in China.展开更多
Wheat dwarf virus （WDV）, an important cereal pathogen, is closely related to Maize streak virus （MSV）, a model virus of the Mastrevirus genus. Based on its similarity to known MSV resistance strategies, a truncate...Wheat dwarf virus （WDV）, an important cereal pathogen, is closely related to Maize streak virus （MSV）, a model virus of the Mastrevirus genus. Based on its similarity to known MSV resistance strategies, a truncated part of the WDV replication- associated （RepA） gene （WDVRepA215） and the WDV RepA gene with a mutated retinoblastoma-related protein （RBR） interaction domain （WDVRepA215RBRre^t） were cloned into the plPKb002 expression vector and transformed into immature embryos of spring barley cv. Golden Promise plants through Agrobacterium-mediated transformation. A detailed study of T1-generation plants infected by leafhoppers （Psammotettix alienus） fed on infection sources of variable strength was performed over a 5-week period encompassing the initial stages of virus infection. A DNA WDV TaqMan qPCR assay normalized using the DNA puroindoline-b SYBR Green qPCR assay for samples on a per week basis revealed an approximately 2-week delay in WDVRepA215RBR^mut plants to WDVRepA215 plants before significant increases in the WDV viral levels occurred. Both WDVRepA215 and WDVRepA215RBR^mut plants showed similar levels of transgenic transcripts over the screened period; however, the transgenic plants also showed increased numbers of infected plants compared to the control plants.展开更多
Common wheat is the major cereal crop that underpins the food safety of China. Both winter wheat and spring wheat are grown on ~24 million ha. This review aims to summarize the current status of wheat production and b...Common wheat is the major cereal crop that underpins the food safety of China. Both winter wheat and spring wheat are grown on ~24 million ha. This review aims to summarize the current status of wheat production and breeding progress in the northern wheat production areas of the country, and to review recently advanced technologies being applied in wheat breeding, including the use of dwarf-male-sterile(DMS) wheat, speed breeding and specialized wheat breeding SNP chips. Crossing is the initial step in most breeding programs. DMS wheat is a convenient tool for large scale production of hybrid seed. Speed breeding or accelerated generation turnover attempts to reduce the time taken in cultivar development. Several different SNP chips are high-throughput, genome-wide genotyping platforms for breeding and research.展开更多
Gibberellin 3-oxidase catalyzes the conversion of inactive gibberellin(GA) species into GAs with biological activity and it is subjected to strict developmental controls in the life cycle of a plant. In this study, 33...Gibberellin 3-oxidase catalyzes the conversion of inactive gibberellin(GA) species into GAs with biological activity and it is subjected to strict developmental controls in the life cycle of a plant. In this study, 33 gene sequences, encoding the gibberellin 3-oxidase(GA3ox) from Dasypyrum villosum and its dwarf mutant, were obtained. Each contained a 1 107 bp coding sequence(CDS) that encoded a putative protein containing 369 amino acids. The GA3ox protein showed 77% to 97% homology and shared the major conserved structural domains of GA3ox proteins with rice, sorghum bicolor, oat, barley, and wheat. Sequence alignment showed that there were 20 single nucleotide polymorphisms(SNPs) and 22 Insertion/deletions(In Dels) among these sequences, which could be divided into 2 haplotypes, haplotypes Ⅰ and Ⅱ. Haplotype Ⅰ was found in the wild type and was1 495 bp in length, and haplotype Ⅱ was found in the dwarf mutant and was 1 485 bp in length. The Q-PCR results showed that GA3ox was expressed in the leaves, roots, internodes, and stem nodes, and that there was a significant difference in the transcript level of the GA3ox between the wild type and dwarf mutant. The transcript levels of GA3ox in the leaves at the seedling stage, stem elongation stage and the heading stage, in the root and stem nodes at the stem elongation stage and in the internodes at the heading stage of the wild type, were significantly higher than those in the dwarf mutant. However, GA3ox expression in the rest of the wild type tissues at the 3 stages was slightly higher than or not different from the dwarf mutant.The results suggested that the wild type and mutant allele sequences of GA3ox in D. villosum showed 2 amino acid changes in exons and variations in the lengths of introns or the SNPs in introns, which most probably impaired the function of the enzyme,affected the GA3ox expression level, and eventually gave rise to dwarfing.展开更多
基金Supported by Innovation Center of Agricultural Sciences,HubeiProvince~~
文摘[Purpose] The paper is to discuss the high-efficient breeding technology platform of dwarf male-sterile wheat.[Method] Conclusion was made upon the development of the creation and application of dwarf male-sterile wheat,and the conception of introducing haploid breeding technology into the technological system of high-efficient breeding of dwarf male-sterile wheat was proposed.[Result] Dwarf male-sterile wheat not only retains the properties of total male abortion of Taigu Genetic Sterile Wheat,steady sterility,and high hybrid rate after open pollination,but also has the characteristic of high dwarfing ability of Aibian No.1,becoming a comparatively ideal population modification means.At present,the application of dwarf male-sterile wheat mainly includes germplasm resources platform of population modification by using dwarf male-sterile wheat,technology platform of constructing new high-efficient breeding system by using dwarf male-sterile wheat,and production platform of using dwarf male-sterile wheat to breed new varieties.Through the introduction of haploid breeding into the already established wheat high-efficient breeding system,a new system of high-efficient biological breeding technology of dwarf male-sterile wheat was constructed theoretically.[Conclusion] The study provides references to the further study and application of dwarf male-sterile wheat.
基金supported by the National High-Tech R&D Program of China (863 Program, 2006AA100201,2006AA100223)the National Basic Research Programof China (973 Program, 2006CB708208)+1 种基金the 111 Pro-gram of Introducing Talents of Discipline to Universi-ties of China (111-2-16)the ACIAR Program of Australia (CIM/2005/111)
文摘Understanding the effects of wheat dwarfing genes on the coleoptile length and plant height is crucial for the proper utilization of dwarfing genes in the improvement of wheat yield. Molecular marker analysis combined with pedigree information were used to classify wheat cultivars widely planted in major wheat growing regions in China into different categories based on the dwarfing genes they carried. The effects of the dwarfing genes with different sensitivity to gibberellins （GA3） on the coleoptile length and plant height were analyzed. Screening of 129 cultivars by molecular marker analysis revealed that 58 genotypes of wheat contained the dwarfing gene Rht-B1b, 24 genotypes of wheat contained Rht-D1b gene and 73 genotypes of wheat possessed Rht8 gene. In addition, among these 129 cultivars, 35 genotypes of wheat cultivars contained both Rht-B1b and Rht8 genes and 16 genotypes of wheat cultivars contained both Rht-D1b and Rht8 genes. Wheat cultivars with the dwarfing genes Rht-B1b or Rht-D1b were insensitive to GA3, while the cultivars with the dwarfing gene Rht8 were sensitive to GA3. Most of the wheat genotypes containing combination of Rht8 gene with either Rht-B1b or Rht-D1b gene were insensitive to GA3. The plant height was reduced by 24.6, 30.4, 28.2, and 32.2%, respectively, for the wheat cultivars containing Rht-B1b, Rht-D1b, Rht-B1b ＋ Rht8, and Rht-D1b ＋ Rht8 genes. The plant height was reduced by 14.3% for the wheat cultivar containing GA3-sensitive gene Rht8. The coleoptile length was shortened by 25.4, 31.3, 28.4 and 31.3%, respectively, in the wheat cultivars containing Rht-B1b, Rht-D1b, Rht-B1b ＋Rht8 and Rht-D1b ＋ Rht8 genes, while the coleoptile length was shortened only by 6.2% for the wheat cultivar containing Rht8 gene. We conclude that GA3-insensitive dwarfing genes （Rht-B1b and Rht-D1b） are not suitable for the wheat improvement in dryland because these two genes have effect on reducing both plant height and coleoptile length. In contrast, GA3- sensitive dwarfing gene （Rht8） is a relatively ideal candidate for the wheat improvement since it significantly reduces the plant height of wheat, but has less effect on the coleoptile length.
基金supported by the National 863 Program of China (2012AA101105)the Henan Key Scientific and Technological Project, China (122101110200)
文摘Plant height and fertility are two important traits of wheat (Triticum aestivum L.), whose mutants are ideal materials for studies on molecular mechanisms of stem and lforal organ development. In this study, we identiifed a dwarf, multi-pistil and male sterile (dms hereafter) wheat mutant from Zhoumai 18. Simple sequence repeat (SSR) marker assay with 181 primer pairs showed that only one locus of GWM148-2B was divergent between Zhoumai 18 and dms. There were three typical phenotypes in the progeny of dms, tal (T;ca. 0.8 m), semi-dwarf (M;ca. 0.6 m) and dwarf (D;under 0.3 m) plants. Morphological investigation indicated that the internode length of M was shortened by about 20–50 mm each;the internode number of D was 2 less than that of T and Zhoumai 18, and its internode length was shorter also. The pol en vigor and hybridization test demonstrated that dms mutant was male sterility. Segregated phenotypes in progeny of M suggested that the multi-pistils and sterility were control ed by one recessive gene locus which was designated as dms temporarily, and the plant height was control ed by a semi-dominant gene locus Dms. Therefore, progeny individuals of the dms had three genotypes, DmsDms for tal plants, Dmsdms for semi-dwarf plants and dmsdms for dwarf plants. The mutant progenies were individual y selected and propagated for more than 6 generations, thus a set of near isogenic lines of T, M and D for dms were developed. This study provides a set germplasms for studies on molecular mechanisms of wheat stem and spike development.
基金This work was supported by Science and Technology Commission of Chongqing Municipality for the Project“Innovation of Genetic Resources of Wheat"by the National Natural Science Foundation of China for the Project“Studies of Mutialelie Polymorphism of Dominant Dwarfing Genes in Wheat(30370875/C02020502)”.
文摘Dwarfing breeding of wheat in the world is confined to the exploitation of recessive dwarfing sources. None of the dominant dwarfing sources discovered in common wheat (Triticum aestivum L.) has found wide exploitation in wheat breeding due to the extreme dwarfness of their plants (2055 cm). We found in our work that some stable mutant lines with their plant height enhanced to different extents could be obtained in large populations derived from the stock seeds of the dominant dwarfing sources Aibian1 carrying Rht10 on 4DS and being 2055 cm tall and Aisu2 carrying Rht3 on 4BS and being 55 cm tall, or from their descendants of induced mutation treatments, or from the segregating descendants of their crosses with mid- or tall-statured genotypes. Subsequently, we studied these mutation-derived lines differing in plant height with near isogenic lines and observed that the character of their enhanced plant height bred true, each carrying a semi-dominant dwarfing gene for a definite height and that as the plant height of the mutation-derived lines increased, the yield-contributing characters of their near isogenic lines were significantly improved. When test crosses with marker genes and physiological and biochemical genetic marker tests were performed to re-localize the semi-dominant dwarfing genes carried by the mutation-derived lines, it was confirmed that they shared common loci with Rht10 and Rht3 and that they were all mutation-derived multiple alleles. It is thus speculated that dominant dwarfing genes are of 'multi-allelic polymorphism'. In other words, dominant dwarfing genes, which are ultra-dwarfing, are liable to develop by mutation into a group of multiple alleles with plant height enhanced to different extents and some may have a height close to the ideal plant height for wheat breeding. Therefore, these results offer a fundamentally new approach for the exploitation of dominant dwarfing sources in wheat breeding.
基金supported by the Provincial Natural Science Foundation of Hebei,China(396313).
文摘The value of different dwarfing genes in winter wheat breeding was studied using 6 near-isogenic lines carrying different Rht dwarfing genes over three years experiment.Results showed that both the Rht1 and Rht2 semi-dwarfing genes had significantlypositive effects on kernel number and grain weight per spike, and had significantlynegative effects on 1000-grain weight comparing to the tall line(rht) and the Rht3 line.The Rht3 dwarfing gene had a significantly negative effect on kernel number per spike,and had positive effect on 1000-grain weight. The combination of the Rht2 and Rht3 geneshowed significantly negative effect on yield components. All of these 5 dwarfing orsemidwarfing genotypes mentioned above had a significantly negative effect on plantheight and no significant effect on the area of flag leaf, spikelets per spike and spikelength.
基金supported by the National Basic Research and Development Program of China (2009CB119200,2002CB111405)the project from Ministry of Agriculture of China
文摘Wheat dwarf bunt, caused by Tilletia controversa Kühn （TCK）, is an important quarantine wheat disease throughout the world. Based on published research results of the biology and the epidemiology of the disease, the main factors including temperature, humidity, snow cover, and their parameters relating to teliospore germination, infection and epidemics of TCK were determined. The geophytopathological models for the risk analysis of wheat dwarf bunt establishment were modified. Fifty-year meteorologic data from about 500 weather stations in China were used to calculate the probabilities of TCK establishment in different geographic sites with the models. The map that displays the establishment risk of TCK in winter wheat growing regions in China was generated by using geographical information system （GIS）. The zones showing high, moderate, low, and very low, including no risk, of TCK establishment accounted for 27.33, 27.69, 38.12, and 6.86% of total winter wheat growing areas in China, respectively. These results will provide useful information to formulate quarantine regulations and wheat importation policy in China.
基金the Czech Ministry of Education, Youth and Sports funding programme LH12161the Czech Ministry of Agriculture funding programme MZE RO0417
文摘Wheat dwarf virus （WDV）, an important cereal pathogen, is closely related to Maize streak virus （MSV）, a model virus of the Mastrevirus genus. Based on its similarity to known MSV resistance strategies, a truncated part of the WDV replication- associated （RepA） gene （WDVRepA215） and the WDV RepA gene with a mutated retinoblastoma-related protein （RBR） interaction domain （WDVRepA215RBRre^t） were cloned into the plPKb002 expression vector and transformed into immature embryos of spring barley cv. Golden Promise plants through Agrobacterium-mediated transformation. A detailed study of T1-generation plants infected by leafhoppers （Psammotettix alienus） fed on infection sources of variable strength was performed over a 5-week period encompassing the initial stages of virus infection. A DNA WDV TaqMan qPCR assay normalized using the DNA puroindoline-b SYBR Green qPCR assay for samples on a per week basis revealed an approximately 2-week delay in WDVRepA215RBR^mut plants to WDVRepA215 plants before significant increases in the WDV viral levels occurred. Both WDVRepA215 and WDVRepA215RBR^mut plants showed similar levels of transgenic transcripts over the screened period; however, the transgenic plants also showed increased numbers of infected plants compared to the control plants.
基金Financial support provided by the National Key Research and Development Program of China (2017YFD0101000)the Agricultural Science and Technology Innovation Program is acknowledged
文摘Common wheat is the major cereal crop that underpins the food safety of China. Both winter wheat and spring wheat are grown on ~24 million ha. This review aims to summarize the current status of wheat production and breeding progress in the northern wheat production areas of the country, and to review recently advanced technologies being applied in wheat breeding, including the use of dwarf-male-sterile(DMS) wheat, speed breeding and specialized wheat breeding SNP chips. Crossing is the initial step in most breeding programs. DMS wheat is a convenient tool for large scale production of hybrid seed. Speed breeding or accelerated generation turnover attempts to reduce the time taken in cultivar development. Several different SNP chips are high-throughput, genome-wide genotyping platforms for breeding and research.
文摘Gibberellin 3-oxidase catalyzes the conversion of inactive gibberellin(GA) species into GAs with biological activity and it is subjected to strict developmental controls in the life cycle of a plant. In this study, 33 gene sequences, encoding the gibberellin 3-oxidase(GA3ox) from Dasypyrum villosum and its dwarf mutant, were obtained. Each contained a 1 107 bp coding sequence(CDS) that encoded a putative protein containing 369 amino acids. The GA3ox protein showed 77% to 97% homology and shared the major conserved structural domains of GA3ox proteins with rice, sorghum bicolor, oat, barley, and wheat. Sequence alignment showed that there were 20 single nucleotide polymorphisms(SNPs) and 22 Insertion/deletions(In Dels) among these sequences, which could be divided into 2 haplotypes, haplotypes Ⅰ and Ⅱ. Haplotype Ⅰ was found in the wild type and was1 495 bp in length, and haplotype Ⅱ was found in the dwarf mutant and was 1 485 bp in length. The Q-PCR results showed that GA3ox was expressed in the leaves, roots, internodes, and stem nodes, and that there was a significant difference in the transcript level of the GA3ox between the wild type and dwarf mutant. The transcript levels of GA3ox in the leaves at the seedling stage, stem elongation stage and the heading stage, in the root and stem nodes at the stem elongation stage and in the internodes at the heading stage of the wild type, were significantly higher than those in the dwarf mutant. However, GA3ox expression in the rest of the wild type tissues at the 3 stages was slightly higher than or not different from the dwarf mutant.The results suggested that the wild type and mutant allele sequences of GA3ox in D. villosum showed 2 amino acid changes in exons and variations in the lengths of introns or the SNPs in introns, which most probably impaired the function of the enzyme,affected the GA3ox expression level, and eventually gave rise to dwarfing.
