Saline-alkali soil severely reduces the productivity of crops,including maize(Zea mays).Although several genes associated with saline-alkali tolerance have been identified in maize,the underlying regulatory mechanism ...Saline-alkali soil severely reduces the productivity of crops,including maize(Zea mays).Although several genes associated with saline-alkali tolerance have been identified in maize,the underlying regulatory mechanism remains elusive.Here,we report a direct link between colonization by arbuscular mycorrhizal fungi(AMF)and saline-alkali tolerance in maize.We identify s75,a natural maize mutant that cannot survive under moderate saline-alkali soil conditions or establish AM symbioses.The saline-alkali hypersensitive phenotype of s75 is caused by a 1340-bp deletion in Zm00001d033915,designated as ZmL75.This gene encodes a glycerol-3-phosphate acyltransferase localized in the endoplasmic reticulum,and is responsible for AMF colonization.ZmL75 expression levels in roots correspond with the root length colonization(RLC)rate during early vegetative development.Notably,the s75 mutant line shows a complete loss of AMF colonization,along with alterations in the diversity and structure of its root fungal microbiota.Conversely,overexpression of ZmL75 increases the RLC rate and enhances tolerance to saline-alkali soil conditions.These results suggest that ZmL75 is required for symbiosis with AMF,which directly improves saline-alkali tolerance.Our findings provide insights into maize-AMF interactions and offer a potential strategy for maize improvement.展开更多
Maize root system plays a crucial role in the development of the aboveground plant and determines the yield through the uptake of water and nutrients in the field.However,the genetic architecture of the maize root sys...Maize root system plays a crucial role in the development of the aboveground plant and determines the yield through the uptake of water and nutrients in the field.However,the genetic architecture of the maize root system is largely unknown mainly due to its complexity and the interactions between genotype and environment.Using a high-throughput semi-automatic hydroponic platform with stable conditions,we comprehensively characterized the root system in a core population of 518 diverse inbred lines of maize.Population structure analysis revealed that the panel has stratification and a linkage disequilibrium decay distance of less than 50 kb.Based on genotyping with the high-density 600 K SNPs,we conducted a genome wide association analysis(GWAS)and identified nine SNPs and seven candidate genes significantly associated with 24 traits.One candidate gene,GRMZM2G400533,is located at the upstream 5 kb region from the leading SNP(AX-91771718)and was significantly associated with primary root length and preferentially expressed in the primary root and crown root.Expression of GRMZM2G400533 increased as the primary root developed but was negatively correlated with primary root elongation.An analysis of candidate gene GRMZM2G400533 identified three functional variants and eight allelic haplotypes.This study will broaden our understanding of maize root development and provide a theoretical basis for maize improvement through optimization of the root system.展开更多
Drought is one of the most critical abiotic stresses influencing maize yield. Improving maize cultivars with drought tolerance using marker-assisted selection requires a better understanding of its genetic basis. In t...Drought is one of the most critical abiotic stresses influencing maize yield. Improving maize cultivars with drought tolerance using marker-assisted selection requires a better understanding of its genetic basis. In this study, a doubled haploid(DH) population consisting of 217 lines was created by crossing the inbred lines Han 21(drought-tolerant) and Ye 478(drought-sensitive). The population was genotyped with a 6 K SNP assay and 756 SNP(single nucleotide polymorphism) markers were used to construct a linkage map with a length of 1344 c M. Grain yield(GY), ear setting percentage(ESP), and anthesis–silking interval(ASI) were recorded in seven environments under well-watered(WW) and water-stressed(WS) regimes. High phenotypic variation was observed for all traits under both water regimes. Using the LSMEAN(least-squares mean) values from all environments for each trait, 18 QTL were detected, with 9 associated with the WW and 9 with the WS regime. Four chromosome regions,Chr. 3: 219.8–223.7 Mb, Chr. 5: 191.5–194.7 Mb, Chr. 7: 132.2–135.6 Mb, and Chr. 10: 88.2–89.4 Mb, harbored at least 2 QTL in each region, and QTL co-located in a region inherited favorable alleles from the same parent. A set of 64 drought-tolerant BC_3F_6 lines showed preferential accumulation of the favorable alleles in these four regions, supporting an association between the four regions and maize drought tolerance. QTL-by-environment interaction analysis revealed 28 ed QTL(environment-dependent QTL) associated with the WS regime and 22 associated with the WW regime for GY, ESP, and ASI. All WS QTL and55.6% of WW QTL were located in the ed QTL regions. The hotspot genomic regions identified in this work will support further fine mapping and marker-assisted breeding of drought-tolerant maize.展开更多
基金National Natural Science Foundation of China(No.32171947 and No.31671699)which supported this research.
文摘Saline-alkali soil severely reduces the productivity of crops,including maize(Zea mays).Although several genes associated with saline-alkali tolerance have been identified in maize,the underlying regulatory mechanism remains elusive.Here,we report a direct link between colonization by arbuscular mycorrhizal fungi(AMF)and saline-alkali tolerance in maize.We identify s75,a natural maize mutant that cannot survive under moderate saline-alkali soil conditions or establish AM symbioses.The saline-alkali hypersensitive phenotype of s75 is caused by a 1340-bp deletion in Zm00001d033915,designated as ZmL75.This gene encodes a glycerol-3-phosphate acyltransferase localized in the endoplasmic reticulum,and is responsible for AMF colonization.ZmL75 expression levels in roots correspond with the root length colonization(RLC)rate during early vegetative development.Notably,the s75 mutant line shows a complete loss of AMF colonization,along with alterations in the diversity and structure of its root fungal microbiota.Conversely,overexpression of ZmL75 increases the RLC rate and enhances tolerance to saline-alkali soil conditions.These results suggest that ZmL75 is required for symbiosis with AMF,which directly improves saline-alkali tolerance.Our findings provide insights into maize-AMF interactions and offer a potential strategy for maize improvement.
基金supported by the National Natural Science Foundation of China(32160440)the Manas County National Hybrid Corn Seed Production Base Construction Project,China(MNSZZDX-2021-01)the National Key Research and Development Programs of China(2022YFF1003304)。
文摘Maize root system plays a crucial role in the development of the aboveground plant and determines the yield through the uptake of water and nutrients in the field.However,the genetic architecture of the maize root system is largely unknown mainly due to its complexity and the interactions between genotype and environment.Using a high-throughput semi-automatic hydroponic platform with stable conditions,we comprehensively characterized the root system in a core population of 518 diverse inbred lines of maize.Population structure analysis revealed that the panel has stratification and a linkage disequilibrium decay distance of less than 50 kb.Based on genotyping with the high-density 600 K SNPs,we conducted a genome wide association analysis(GWAS)and identified nine SNPs and seven candidate genes significantly associated with 24 traits.One candidate gene,GRMZM2G400533,is located at the upstream 5 kb region from the leading SNP(AX-91771718)and was significantly associated with primary root length and preferentially expressed in the primary root and crown root.Expression of GRMZM2G400533 increased as the primary root developed but was negatively correlated with primary root elongation.An analysis of candidate gene GRMZM2G400533 identified three functional variants and eight allelic haplotypes.This study will broaden our understanding of maize root development and provide a theoretical basis for maize improvement through optimization of the root system.
基金supported by the National Key Research and Development Program of China(2016YFD0101803)the Key Transgenic Breeding Program of the Ministry of Agriculture of China(2016ZX08003-002)the China Agriculture Research System(CARS-02-10)。
文摘Drought is one of the most critical abiotic stresses influencing maize yield. Improving maize cultivars with drought tolerance using marker-assisted selection requires a better understanding of its genetic basis. In this study, a doubled haploid(DH) population consisting of 217 lines was created by crossing the inbred lines Han 21(drought-tolerant) and Ye 478(drought-sensitive). The population was genotyped with a 6 K SNP assay and 756 SNP(single nucleotide polymorphism) markers were used to construct a linkage map with a length of 1344 c M. Grain yield(GY), ear setting percentage(ESP), and anthesis–silking interval(ASI) were recorded in seven environments under well-watered(WW) and water-stressed(WS) regimes. High phenotypic variation was observed for all traits under both water regimes. Using the LSMEAN(least-squares mean) values from all environments for each trait, 18 QTL were detected, with 9 associated with the WW and 9 with the WS regime. Four chromosome regions,Chr. 3: 219.8–223.7 Mb, Chr. 5: 191.5–194.7 Mb, Chr. 7: 132.2–135.6 Mb, and Chr. 10: 88.2–89.4 Mb, harbored at least 2 QTL in each region, and QTL co-located in a region inherited favorable alleles from the same parent. A set of 64 drought-tolerant BC_3F_6 lines showed preferential accumulation of the favorable alleles in these four regions, supporting an association between the four regions and maize drought tolerance. QTL-by-environment interaction analysis revealed 28 ed QTL(environment-dependent QTL) associated with the WS regime and 22 associated with the WW regime for GY, ESP, and ASI. All WS QTL and55.6% of WW QTL were located in the ed QTL regions. The hotspot genomic regions identified in this work will support further fine mapping and marker-assisted breeding of drought-tolerant maize.
