Grain filling is the physiological process for determining the obtainment of yield in cereal crops.The grain-filling characteristics of 50 maize brand hybrids released from 1964 to 2014 in China were assayed across mu...Grain filling is the physiological process for determining the obtainment of yield in cereal crops.The grain-filling characteristics of 50 maize brand hybrids released from 1964 to 2014 in China were assayed across multiple environments.We found that the grain-filling duration(54.46%)and rate(43.40%)at the effective grain-filling phase greatly contributed to the final performance parameter of 100-kernel weight(HKW).Meanwhile,along with the significant increase in HKW,the accumulated growing degree days(GDDs)for the actual grain-filling period duration(AFPD)among the selected brand hybrids released from the 1960s to the 2010s in China had a decadal increase of 23.41℃ d.However,there was a decadal increase of only 19.76℃ d for GDDs of the days from sowing to physiological maturity(DPM),which was also demonstrated by a continuous decrease in the ratio between the days from sowing to silking(DS)and DPM(i.e.,from 53.24%in the 1960s to 49.78%in the 2010s).In contrast,there were no significant changes in grain-filling rate along with the release years of the selected hybrids.Moreover,the stability of grain-filling characteristics across environments also significantly increased along with the hybrid release years.We also found that the exotic hybrids showed a longer grain-filling duration at the effective grain-filling phase and more stability of the grain-filling characteristics than those of the Chinese local hybrids.According to the results of this study,it is expected that the relatively longer grain-filling duration,shorter DS,higher grain-filling rate,and steady grain-filling characteristics would contribute to the yield improvement of maize hybrids in the future.展开更多
钙调磷酸酶B类互作蛋白激酶(CIPK,CBL interacting protein kinases)是植物钙离子信号通路中响应非生物逆境胁迫的重要蛋白激酶之一。本研究以拟南芥和水稻中CIPK家族基因序列信息为基础,利用玉米参考基因组B73和生物信息学分析方法,全...钙调磷酸酶B类互作蛋白激酶(CIPK,CBL interacting protein kinases)是植物钙离子信号通路中响应非生物逆境胁迫的重要蛋白激酶之一。本研究以拟南芥和水稻中CIPK家族基因序列信息为基础,利用玉米参考基因组B73和生物信息学分析方法,全基因组范围内鉴定玉米CIPK基因家族成员,分析CIPK家族基因的进化关系、基因结构、基因表达模式和对干旱胁迫的响应。本研究共鉴定出44个玉米CIPK家族基因,并将其分为5个亚家族,每个亚家族有不同的外显子-内含子和UTR的结构特征;基于基因差异表达分析,筛选出5个与抗旱性相关的候选基因ZmCIPK3、ZmCIPK7、ZmCIPK44、ZmCIPK25和ZmCIPK28;进一步的遗传数据表明,干旱胁迫下ZmCIPK3拟南芥转基因株系的存活率明显高于野生型,提高了拟南芥的抗旱性;同时,干旱胁迫下ZmCIPK3拟南芥转基因株系中抗旱性相关生化指标过氧化物酶、超氧化物歧化酶活性显著高于野生型,而丙二醛和脯氨酸的含量显著低于野生型。本研究在玉米全基因组水平上鉴定了CIPK基因家族成员,分析了其在不同抗旱性材料、不同水分处理下的基因表达模式,明确了ZmCIPK3是一个抗旱性候选基因。展开更多
Better understanding of genotype-by-environment interaction(GEI)is expected to provide a solid foundation for genetic improvement of crop productivity especially under drought-prone environments.To elucidate the genet...Better understanding of genotype-by-environment interaction(GEI)is expected to provide a solid foundation for genetic improvement of crop productivity especially under drought-prone environments.To elucidate the genetic basis of the plant and ear height,2 F2:3 populations were derived from the crosses of Qi 319 × Huangzaosi(Q/H)and Ye 478 × Huangzaosi(Y/H)with 230 and 235 families,respectively,and their parents were evaluated under 3 diverse environments in Henan,Beijing,and Xinjiang,China during the year of 2007 and 2008,and all the lines were also evaluated under water stress environment.The mapping results showed that a total of 21 and 12 QTLs were identified for plant height in the Q/H and Y/H population,respectively,and 24 and 13 QTLs for ear height,respectively.About 56 and 73% of the QTLs for 2 traits did not present significant QTL-by-environment interaction(QEI)in the normal joint analyses for Q/H and Y/H population,respectively,and about 73% of the QTLs detected did not show significant QEI according to joint analyses for stress condition in Q/H.Most of the detected major QTLs exhibited high stability across different environments.Besides,several major QTLs were detected with large and consistent effect under normal condition(Chr.6 and 7 in Q/H;Chr.1,3 and 9 in Y/H),or across 2 water regimes(Chr.1,8 and 10 for in Q/H).There were several constitutive QTLs(3 for Q/H and 1 for Y/H)with no or minor QTL-by-environment for the 2 populations.Finally,we found several genomic regions(Chr.1,10,etc.)to be co-located across the populations,which could provide useful reference for genetic improvement of these traits in maize breeding programs.Comparative genomic analysis revealed that 3 genes/genetic segments associated with plant height in rice were orthologous to these 3 identified genomic regions carrying the major QTLs for plant and ear height on Chr.1,6,and 8,respectively.展开更多
In this study, a forward cDNA library was constructed by suppression subtractive hybridization using seedling leaves of CN165, a drought-tolerant maize inbred line. In the suppression subtractive hybridization (SSH) l...In this study, a forward cDNA library was constructed by suppression subtractive hybridization using seedling leaves of CN165, a drought-tolerant maize inbred line. In the suppression subtractive hybridization (SSH) library, 672 positive clones were picked up randomly. After polymerase chain reaction (PCR) of each clone, all the single clones were sequenced. Totally 598 available sequences were obtained. After cluster analysis of the EST sequences, 80 uniESTs were obtained, among which 57 uniESTs were contigs and 23 uniESTs were singlets. The results of BLASTN showed that all the uniESTs had homologous sequences in the nr database. The BLASTX results indicated that 68 uniESTs had significant protein homology, 8 uniESTs with homology of unknown proteins and putative proteins, and 4 uniESTs without protein homology. Those drought stress-induced genes were involved in many metabolism pathways to regulate plant growth and development under drought stress.展开更多
Drought is one of the most important abiotic stresses affecting maize growth and development and therefore resulting in yield loss.Thus it is essential to understand molecular mechanisms of drought stress responses in...Drought is one of the most important abiotic stresses affecting maize growth and development and therefore resulting in yield loss.Thus it is essential to understand molecular mechanisms of drought stress responses in maize for drought tolerance improvement.The root plays a critical role in plants sensing water deficit.In the present study,two maize inbred lines,H082183,a drought-tolerant line,and Lv28,a drought-sensitive line,were grown in the field and treated with different water conditions(moderate drought,severe drought,and well-watered conditions)during vegetative stage.The transcriptomes of their roots were investigated by RNA sequencing.There were 1428 and 512 drought-responsive genes(DRGs)in Lv28,688 and 3363 DRGs in H082183 under moderate drought and severe drought,respectively.A total of 31 Gene Ontology(GO)terms were significantly over-represented in the two lines,13 of which were enriched only in the DRGs of H082183.Based on results of Kyoto encyclopedia of genes and genomes(KEGG)enrichment analysis,"plant hormone signal transduction"and"starch and sucrose metabolism"were enriched in both of the two lines,while"phenylpropanoid biosynthesis"was only enriched in H082183.Further analysis revealed the different expression patterns of genes related to abscisic acid(ABA)signal pathway,trehalose biosynthesis,reactive oxygen scavenging,and transcription factors might contribute to drought tolerance in maize.Our results contribute to illustrating drought-responsive molecular mechanisms and providing gene resources for maize drought improvement.展开更多
Both the additive and multiplicative models of crop yield and water supply are polynomial equations,and the number of parameters increases linearly when the growing period is specified.However,interactions among multi...Both the additive and multiplicative models of crop yield and water supply are polynomial equations,and the number of parameters increases linearly when the growing period is specified.However,interactions among multiple parameters occasionally lead to unreasonable estimations of certain parameters,which were water sensitivity coefficients but with negative value.Additionally,evapotranspiration must be measured as a model input.To facilitate the application of these models and overcome the aforementioned shortcomings,a simple model with only three parameters was derived in this paper based on certain general quantitative relations of crop yield(Y) and water supply(W).The new model,Y/Y_m-W^k/(W^k+w_h^k),fits an S or a saturated curve of crop yield with the cumulative amount of water.Three parameters are related to biological factors:the yield potential(Y_m),the water requirement to achieve half of the yield potential(half-yield water requirement,w_h),and the water sensitivity coefficient(k).The model was validated with data from 24 maize lines obtained in the present study and17 maize hybrids published by other authors.The results showed that the model was well fit to the data,and the normal root of the mean square error(NRMSE) values were 2.8 to 17.8%(average 7.2%) for the 24 maize lines and 2.7 to 12.7%(average 7.4%) for the 17 maize varieties.According to the present model,the maize water-sensitive stages in descending order were pollen shedding and silking,tasselling,jointing,initial grain filling,germination,middle grain filling,late grain filling,and end of grain filling.This sequence was consistent with actual observations in the maize field.The present model may be easily used to analyse the water use efficiency and drought tolerance of maize at specific stages.展开更多
Maize landraces White Dent and Golden Queen played a very important role in the pre-hybrid era of maize production in China.However,dozens of accessions with the same names of White Dent and Golden Queen are preserved...Maize landraces White Dent and Golden Queen played a very important role in the pre-hybrid era of maize production in China.However,dozens of accessions with the same names of White Dent and Golden Queen are preserved in China National Genebank(CNG).The present study investigated the genetic diversity of these two important groups of maize landraces,as well as the relationships within and among them.Thirty-four landrace accessions with the name of White Dent and 10 with Golden Queen preserved in CNG were fingerprinted with 52 simple sequence repeats with tailed primer M13.Summary statistics including average number of alleles per locus,gene diversity/expected heterozygosity,and observed heterozygosity were carried out using PowerMarker ver.3.25 software.The test of Hardy-Weinberg equilibrium(HWE) and linkage disequilibrium(LD) of all the 44 maize landrace accessions were also performed by PowerMarker.We observed a significant differentiation in terms of the average number of alleles between White Dent and Golden Queen(6.44 alleles per locus in White Dent,4.48 in Golden Queen),while both groups of maize landraces had a relatively high but similar gene diversity(0.61 of White Dent,0.63 of Golden Queen).The fixation index(FST) was only 0.0044,while the percentage of loci deviated from Hardy-Weinberg equilibrium within these two groups of White Dent and Golden Queen was 32.69 and 3.92%,respectively.The rather high genetic diversity and average number of alleles per locus confirmed that both groups of landraces had a rather broad germplasm base.The extremely low fixation index showed that there was little genetic variation between White Dent and Golden Queen and the molecular variation within these two groups was remarkably high,indicating no genetic drift between White Dent and Golden Queen and suggesting different improvement approaches to these two important groups of landraces.Hardy-Weinberg equilibrium test revealed that the group of White Dent was deviated from HWE,whereas Golden Queen was under HWE.展开更多
Understanding genetic diversity and population structure of landraces is important in utilization of these germplasm in breeding programs. In the present study, a total of 143 core maize landraces from the South Maize...Understanding genetic diversity and population structure of landraces is important in utilization of these germplasm in breeding programs. In the present study, a total of 143 core maize landraces from the South Maize Region (SR) of China, which can represent the general profile of the genetic diversity in the landraces germplasm of SR, were genotyped by 54 DNA microsatellite markers. Totally, 517 alleles (ranging from 4 to 22) were detected among these landraces, with an average of 9.57 alleles per locus. The total gene diversity of these core landraces was 0.61, suggesting a rather higher level of genetic diversity. Analysis of population structure based on Bayesian method obtained the samilar result as the phylogeny neighbor-joining (NJ) method. The results indicated that the whole set of 143 core landraces could be clustered into two distinct groups. All landraces from Guangdong, Hainan, and 15 landraces from Jiangxi were clustered into group 1, while those from the other regions of SR formed the group 2. The results from the analysis of genetic diversity showed that both of groups possessed a similar gene diversity, but group 1 possessed relatively lower mean alleles per locus (6.63) and distinct alleles (91) than group 2 (7.94 and 110, respectively). The relatively high richness of total alleles and distinct alleles preserved in the core landraces from SR suggested that all these germplasm could be useful resources in germplasm enhancement and maize breeding in China.展开更多
Drought stress affects the growth and productivity of crop plants including sorghum.To study the molecular basis of drought tolerance in sorghum,we conducted the transcriptomic profiling of sorghum leaves and roots un...Drought stress affects the growth and productivity of crop plants including sorghum.To study the molecular basis of drought tolerance in sorghum,we conducted the transcriptomic profiling of sorghum leaves and roots under drought stress using RNA-Seq method.A total of 510,559,and 3 687 differentially expressed genes(DEGs)in leaves,3 368,5 093,and 4 635 DEGs in roots responding to mild drought,severe drought,and re-watering treatments were identified,respectively.Among them,190 common DEGs in leaves and 1 644 common DEGs in roots were responsive to mild drought,severe drought,and re-watering environment.Gene Ontology(GO)enrichment analysis revealed that the GO categories related to drought tolerance include terms related to response to stimulus especially response to water deprivation,abscisic acid stimulus,and reactive oxygen species.The major transcription factor genes responsive to drought stress include heat stress transcription factor(HSF),ethylene-responsive transcription factor(ERF),Petunia NAM,Arabidopsis ATAF1/2 and CUC2(NAC),WRKY transcription factor(WRKY),homeodomain leucine zipper transcription factor(HD-ZIP),basic helix-loop-helix transcription factor(bHLH),and V-myb myeloblastosis viral oncogene homolog transcription facotr(MYB).Functional protein genes for heat shock protein(HSPs),late-embryogenesis-abundant protein(LEAs),chaperones,aquaporins,and expansins might play important roles in sorghum drought tolerance.Moreover,the genomic regions enriched with HSP,expansin,and aquaporin genes responsive to drought stress could be used as powerful targets for improvement of drought tolerance in sorghum and other cereals.Overall,our results provide a genome-wide analysis of DEGs in sorghum leaves and roots under mild drought,severe drought,and re-watering environments.This study contributes to a better understanding of the molecular basis of drought tolerance of sorghum and can be useful for crop improvement.展开更多
Drought stress is one of the most important factors limiting maize production. Rab17 is an ABA-responsive gene and associated with drought tolerance. In order to identify haplotypic structure and mine allelic variants...Drought stress is one of the most important factors limiting maize production. Rab17 is an ABA-responsive gene and associated with drought tolerance. In order to identify haplotypic structure and mine allelic variants at rab17 locus, nucleotide diversity and linkage disequilibrium (LD) structure of rab17 were evaluated among a mini core set of Chinese diversified maize inbred lines. Totally, 19 SNP and 18 insertion/deletions (InDels) were identified, among which 81% were in non-coding regions and 19% in coding regions. The results showed that a high level of diversity appeared within 1 kb upstream of the rab17 locus, and declined quickly downstream of the gene region. Rapid decay of linkage disequilibrium of rab17 region with distance within 1 kb was detected. Functional markers which can be developed based on haplotype 14 are expected to have contribution to molecular breeding for drought tolerance.展开更多
Maize roots are important component for plant adaptation to soil water deficits because they are supposed to take up water and necessary solutes from the soil. In the present study, the drought-induced genes were isol...Maize roots are important component for plant adaptation to soil water deficits because they are supposed to take up water and necessary solutes from the soil. In the present study, the drought-induced genes were isolated in maize roots. A suppression subtractive hybridization protocol was applied to construct a forward subtractive cDNA library from CN165 for drought-stressed maize roots and a number of drought-induced genes were isolated. Totally, 126 uniESTs (containing 82 singlets and 44 contigs) were obtained from 503 available ESTs sequences after macroarray hybridization. UniESTs were analyzed using BLASTN and BLASTX and the results showed that 92% of the uniESTs had homolgous sequences in maize nr database by BLASTN. About 89% of uniESTs appeared the homlogous amino acid sequences in rice protein database but not in maize protein database by BLASTX, implying that those genes are likely new functional genes in maize. Function analysis showed that those genes were involved in a broad spectrum of biological pathways, mainly in signaling and regulatory pathways related to stress tolerance.展开更多
基金partly supported by the National Key R&D Program of China(2016YFD0100303 and 2016YFD0100103)the Fundamental Research Funds for Central Non-Profit of Institute of Crop Sciences,Chinese Academy of Agricultural Sciences(Y2020YJ09 and CAAS-ZDRW202109)the Agricultural Science and Technology Innovation Program,China(ASTIP)。
文摘Grain filling is the physiological process for determining the obtainment of yield in cereal crops.The grain-filling characteristics of 50 maize brand hybrids released from 1964 to 2014 in China were assayed across multiple environments.We found that the grain-filling duration(54.46%)and rate(43.40%)at the effective grain-filling phase greatly contributed to the final performance parameter of 100-kernel weight(HKW).Meanwhile,along with the significant increase in HKW,the accumulated growing degree days(GDDs)for the actual grain-filling period duration(AFPD)among the selected brand hybrids released from the 1960s to the 2010s in China had a decadal increase of 23.41℃ d.However,there was a decadal increase of only 19.76℃ d for GDDs of the days from sowing to physiological maturity(DPM),which was also demonstrated by a continuous decrease in the ratio between the days from sowing to silking(DS)and DPM(i.e.,from 53.24%in the 1960s to 49.78%in the 2010s).In contrast,there were no significant changes in grain-filling rate along with the release years of the selected hybrids.Moreover,the stability of grain-filling characteristics across environments also significantly increased along with the hybrid release years.We also found that the exotic hybrids showed a longer grain-filling duration at the effective grain-filling phase and more stability of the grain-filling characteristics than those of the Chinese local hybrids.According to the results of this study,it is expected that the relatively longer grain-filling duration,shorter DS,higher grain-filling rate,and steady grain-filling characteristics would contribute to the yield improvement of maize hybrids in the future.
文摘钙调磷酸酶B类互作蛋白激酶(CIPK,CBL interacting protein kinases)是植物钙离子信号通路中响应非生物逆境胁迫的重要蛋白激酶之一。本研究以拟南芥和水稻中CIPK家族基因序列信息为基础,利用玉米参考基因组B73和生物信息学分析方法,全基因组范围内鉴定玉米CIPK基因家族成员,分析CIPK家族基因的进化关系、基因结构、基因表达模式和对干旱胁迫的响应。本研究共鉴定出44个玉米CIPK家族基因,并将其分为5个亚家族,每个亚家族有不同的外显子-内含子和UTR的结构特征;基于基因差异表达分析,筛选出5个与抗旱性相关的候选基因ZmCIPK3、ZmCIPK7、ZmCIPK44、ZmCIPK25和ZmCIPK28;进一步的遗传数据表明,干旱胁迫下ZmCIPK3拟南芥转基因株系的存活率明显高于野生型,提高了拟南芥的抗旱性;同时,干旱胁迫下ZmCIPK3拟南芥转基因株系中抗旱性相关生化指标过氧化物酶、超氧化物歧化酶活性显著高于野生型,而丙二醛和脯氨酸的含量显著低于野生型。本研究在玉米全基因组水平上鉴定了CIPK基因家族成员,分析了其在不同抗旱性材料、不同水分处理下的基因表达模式,明确了ZmCIPK3是一个抗旱性候选基因。
基金supported by grants provided by the Ministry of Science and Technology of China(2006CB101700,2009CB118401,2006BAD13B03)National Natural Science Foundation of China(30730063)
文摘Better understanding of genotype-by-environment interaction(GEI)is expected to provide a solid foundation for genetic improvement of crop productivity especially under drought-prone environments.To elucidate the genetic basis of the plant and ear height,2 F2:3 populations were derived from the crosses of Qi 319 × Huangzaosi(Q/H)and Ye 478 × Huangzaosi(Y/H)with 230 and 235 families,respectively,and their parents were evaluated under 3 diverse environments in Henan,Beijing,and Xinjiang,China during the year of 2007 and 2008,and all the lines were also evaluated under water stress environment.The mapping results showed that a total of 21 and 12 QTLs were identified for plant height in the Q/H and Y/H population,respectively,and 24 and 13 QTLs for ear height,respectively.About 56 and 73% of the QTLs for 2 traits did not present significant QTL-by-environment interaction(QEI)in the normal joint analyses for Q/H and Y/H population,respectively,and about 73% of the QTLs detected did not show significant QEI according to joint analyses for stress condition in Q/H.Most of the detected major QTLs exhibited high stability across different environments.Besides,several major QTLs were detected with large and consistent effect under normal condition(Chr.6 and 7 in Q/H;Chr.1,3 and 9 in Y/H),or across 2 water regimes(Chr.1,8 and 10 for in Q/H).There were several constitutive QTLs(3 for Q/H and 1 for Y/H)with no or minor QTL-by-environment for the 2 populations.Finally,we found several genomic regions(Chr.1,10,etc.)to be co-located across the populations,which could provide useful reference for genetic improvement of these traits in maize breeding programs.Comparative genomic analysis revealed that 3 genes/genetic segments associated with plant height in rice were orthologous to these 3 identified genomic regions carrying the major QTLs for plant and ear height on Chr.1,6,and 8,respectively.
文摘In this study, a forward cDNA library was constructed by suppression subtractive hybridization using seedling leaves of CN165, a drought-tolerant maize inbred line. In the suppression subtractive hybridization (SSH) library, 672 positive clones were picked up randomly. After polymerase chain reaction (PCR) of each clone, all the single clones were sequenced. Totally 598 available sequences were obtained. After cluster analysis of the EST sequences, 80 uniESTs were obtained, among which 57 uniESTs were contigs and 23 uniESTs were singlets. The results of BLASTN showed that all the uniESTs had homologous sequences in the nr database. The BLASTX results indicated that 68 uniESTs had significant protein homology, 8 uniESTs with homology of unknown proteins and putative proteins, and 4 uniESTs without protein homology. Those drought stress-induced genes were involved in many metabolism pathways to regulate plant growth and development under drought stress.
基金supported by the Sci-Tech Innovation Program of Chinese Academy of Agricultural Sciences (Y2016PT10)
文摘Drought is one of the most important abiotic stresses affecting maize growth and development and therefore resulting in yield loss.Thus it is essential to understand molecular mechanisms of drought stress responses in maize for drought tolerance improvement.The root plays a critical role in plants sensing water deficit.In the present study,two maize inbred lines,H082183,a drought-tolerant line,and Lv28,a drought-sensitive line,were grown in the field and treated with different water conditions(moderate drought,severe drought,and well-watered conditions)during vegetative stage.The transcriptomes of their roots were investigated by RNA sequencing.There were 1428 and 512 drought-responsive genes(DRGs)in Lv28,688 and 3363 DRGs in H082183 under moderate drought and severe drought,respectively.A total of 31 Gene Ontology(GO)terms were significantly over-represented in the two lines,13 of which were enriched only in the DRGs of H082183.Based on results of Kyoto encyclopedia of genes and genomes(KEGG)enrichment analysis,"plant hormone signal transduction"and"starch and sucrose metabolism"were enriched in both of the two lines,while"phenylpropanoid biosynthesis"was only enriched in H082183.Further analysis revealed the different expression patterns of genes related to abscisic acid(ABA)signal pathway,trehalose biosynthesis,reactive oxygen scavenging,and transcription factors might contribute to drought tolerance in maize.Our results contribute to illustrating drought-responsive molecular mechanisms and providing gene resources for maize drought improvement.
基金supported by grants provided by the National Sci-Tech Key Program of Development of Transgenic Animals and Plants,Ministry of Science and Technology,China(2014ZX08003-004)
文摘Both the additive and multiplicative models of crop yield and water supply are polynomial equations,and the number of parameters increases linearly when the growing period is specified.However,interactions among multiple parameters occasionally lead to unreasonable estimations of certain parameters,which were water sensitivity coefficients but with negative value.Additionally,evapotranspiration must be measured as a model input.To facilitate the application of these models and overcome the aforementioned shortcomings,a simple model with only three parameters was derived in this paper based on certain general quantitative relations of crop yield(Y) and water supply(W).The new model,Y/Y_m-W^k/(W^k+w_h^k),fits an S or a saturated curve of crop yield with the cumulative amount of water.Three parameters are related to biological factors:the yield potential(Y_m),the water requirement to achieve half of the yield potential(half-yield water requirement,w_h),and the water sensitivity coefficient(k).The model was validated with data from 24 maize lines obtained in the present study and17 maize hybrids published by other authors.The results showed that the model was well fit to the data,and the normal root of the mean square error(NRMSE) values were 2.8 to 17.8%(average 7.2%) for the 24 maize lines and 2.7 to 12.7%(average 7.4%) for the 17 maize varieties.According to the present model,the maize water-sensitive stages in descending order were pollen shedding and silking,tasselling,jointing,initial grain filling,germination,middle grain filling,late grain filling,and end of grain filling.This sequence was consistent with actual observations in the maize field.The present model may be easily used to analyse the water use efficiency and drought tolerance of maize at specific stages.
基金supported by the Special Program for Crop Germplasm Resources of the Ministry of Agriculture [(NB07-2130135-(25-30)-05]Natural Science Foundation of Beijing (6071003)+1 种基金Innovation Platform Program for Basic Research of Agricultural Breeding in Beijing (YZPT02-06)Scientific and Technological Key Project in Chongqing for Elite Variety Innovation of Rice and Maize (CSTC 2007AB1045)
文摘Maize landraces White Dent and Golden Queen played a very important role in the pre-hybrid era of maize production in China.However,dozens of accessions with the same names of White Dent and Golden Queen are preserved in China National Genebank(CNG).The present study investigated the genetic diversity of these two important groups of maize landraces,as well as the relationships within and among them.Thirty-four landrace accessions with the name of White Dent and 10 with Golden Queen preserved in CNG were fingerprinted with 52 simple sequence repeats with tailed primer M13.Summary statistics including average number of alleles per locus,gene diversity/expected heterozygosity,and observed heterozygosity were carried out using PowerMarker ver.3.25 software.The test of Hardy-Weinberg equilibrium(HWE) and linkage disequilibrium(LD) of all the 44 maize landrace accessions were also performed by PowerMarker.We observed a significant differentiation in terms of the average number of alleles between White Dent and Golden Queen(6.44 alleles per locus in White Dent,4.48 in Golden Queen),while both groups of maize landraces had a relatively high but similar gene diversity(0.61 of White Dent,0.63 of Golden Queen).The fixation index(FST) was only 0.0044,while the percentage of loci deviated from Hardy-Weinberg equilibrium within these two groups of White Dent and Golden Queen was 32.69 and 3.92%,respectively.The rather high genetic diversity and average number of alleles per locus confirmed that both groups of landraces had a rather broad germplasm base.The extremely low fixation index showed that there was little genetic variation between White Dent and Golden Queen and the molecular variation within these two groups was remarkably high,indicating no genetic drift between White Dent and Golden Queen and suggesting different improvement approaches to these two important groups of landraces.Hardy-Weinberg equilibrium test revealed that the group of White Dent was deviated from HWE,whereas Golden Queen was under HWE.
基金supported by the Program for Germplasm Innovation and Utilization from the Minis-try of Agrculture of China (2006BAD13B03)Beijing Natural Science Foundation (6071003)Doctoral Foundation of Southwest University, China(SWUB2008037)
文摘Understanding genetic diversity and population structure of landraces is important in utilization of these germplasm in breeding programs. In the present study, a total of 143 core maize landraces from the South Maize Region (SR) of China, which can represent the general profile of the genetic diversity in the landraces germplasm of SR, were genotyped by 54 DNA microsatellite markers. Totally, 517 alleles (ranging from 4 to 22) were detected among these landraces, with an average of 9.57 alleles per locus. The total gene diversity of these core landraces was 0.61, suggesting a rather higher level of genetic diversity. Analysis of population structure based on Bayesian method obtained the samilar result as the phylogeny neighbor-joining (NJ) method. The results indicated that the whole set of 143 core landraces could be clustered into two distinct groups. All landraces from Guangdong, Hainan, and 15 landraces from Jiangxi were clustered into group 1, while those from the other regions of SR formed the group 2. The results from the analysis of genetic diversity showed that both of groups possessed a similar gene diversity, but group 1 possessed relatively lower mean alleles per locus (6.63) and distinct alleles (91) than group 2 (7.94 and 110, respectively). The relatively high richness of total alleles and distinct alleles preserved in the core landraces from SR suggested that all these germplasm could be useful resources in germplasm enhancement and maize breeding in China.
基金support of Innovation Program of Chinese Academy of Agricultural Sciencesthe Major Projects of Genetically Modified Organisms, China (2016ZX08003004)
文摘Drought stress affects the growth and productivity of crop plants including sorghum.To study the molecular basis of drought tolerance in sorghum,we conducted the transcriptomic profiling of sorghum leaves and roots under drought stress using RNA-Seq method.A total of 510,559,and 3 687 differentially expressed genes(DEGs)in leaves,3 368,5 093,and 4 635 DEGs in roots responding to mild drought,severe drought,and re-watering treatments were identified,respectively.Among them,190 common DEGs in leaves and 1 644 common DEGs in roots were responsive to mild drought,severe drought,and re-watering environment.Gene Ontology(GO)enrichment analysis revealed that the GO categories related to drought tolerance include terms related to response to stimulus especially response to water deprivation,abscisic acid stimulus,and reactive oxygen species.The major transcription factor genes responsive to drought stress include heat stress transcription factor(HSF),ethylene-responsive transcription factor(ERF),Petunia NAM,Arabidopsis ATAF1/2 and CUC2(NAC),WRKY transcription factor(WRKY),homeodomain leucine zipper transcription factor(HD-ZIP),basic helix-loop-helix transcription factor(bHLH),and V-myb myeloblastosis viral oncogene homolog transcription facotr(MYB).Functional protein genes for heat shock protein(HSPs),late-embryogenesis-abundant protein(LEAs),chaperones,aquaporins,and expansins might play important roles in sorghum drought tolerance.Moreover,the genomic regions enriched with HSP,expansin,and aquaporin genes responsive to drought stress could be used as powerful targets for improvement of drought tolerance in sorghum and other cereals.Overall,our results provide a genome-wide analysis of DEGs in sorghum leaves and roots under mild drought,severe drought,and re-watering environments.This study contributes to a better understanding of the molecular basis of drought tolerance of sorghum and can be useful for crop improvement.
基金supported by the National Basic Research Program of China (973 Program, 2011CB100105)the National High-Tech R&D Program (863 Program,2006AA10Z188)the National Natural Science Foundation of China (30730063)
文摘Drought stress is one of the most important factors limiting maize production. Rab17 is an ABA-responsive gene and associated with drought tolerance. In order to identify haplotypic structure and mine allelic variants at rab17 locus, nucleotide diversity and linkage disequilibrium (LD) structure of rab17 were evaluated among a mini core set of Chinese diversified maize inbred lines. Totally, 19 SNP and 18 insertion/deletions (InDels) were identified, among which 81% were in non-coding regions and 19% in coding regions. The results showed that a high level of diversity appeared within 1 kb upstream of the rab17 locus, and declined quickly downstream of the gene region. Rapid decay of linkage disequilibrium of rab17 region with distance within 1 kb was detected. Functional markers which can be developed based on haplotype 14 are expected to have contribution to molecular breeding for drought tolerance.
基金The research was supported bythe National Natural Science Foundation of China(30730063) 973 Program of China (2006CB101700)the National Technology R&D Program of China(2006BAD13B03).
文摘Maize roots are important component for plant adaptation to soil water deficits because they are supposed to take up water and necessary solutes from the soil. In the present study, the drought-induced genes were isolated in maize roots. A suppression subtractive hybridization protocol was applied to construct a forward subtractive cDNA library from CN165 for drought-stressed maize roots and a number of drought-induced genes were isolated. Totally, 126 uniESTs (containing 82 singlets and 44 contigs) were obtained from 503 available ESTs sequences after macroarray hybridization. UniESTs were analyzed using BLASTN and BLASTX and the results showed that 92% of the uniESTs had homolgous sequences in maize nr database by BLASTN. About 89% of uniESTs appeared the homlogous amino acid sequences in rice protein database but not in maize protein database by BLASTX, implying that those genes are likely new functional genes in maize. Function analysis showed that those genes were involved in a broad spectrum of biological pathways, mainly in signaling and regulatory pathways related to stress tolerance.
