Twenty-seven favorable teosinte alleles reducing cadmium accumulation or enhancing tolerance were identified across 44 QTLs, and three promising candidate genes for the qCCA3-3 locus were further screened through integrated RNA-seq and qRT-PCR. Cadmium (Cd) contamination in agricultural soils poses serious threats to food security and human health through crop bioaccumulation. This study integrated quantitative trait locus (QTL) mapping in a large maize–teosinte BC2S3 recombinant inbred line population (866 lines genotyped with 19,838 single nucleotide polymorphism markers) with transcriptome profiling to dissect the genetic basis of Cd accumulation and tolerance in maize seedlings. A total of 44 QTLs distributed across all ten chromosomes were identified, each explaining 1.4–6.6

Maize (Zea mays L.) is a globally significant crop, with its kernel sugar content playing a crucial role in determining nutritional quality and industrial applications. This study aimed to elucidate the genetic mechanisms underlying sugar-related traits in maize kernels through genome-wide association studies. We evaluated 495 maize inbred lines for reducing sugar content, soluble sugar content, and the reducing/soluble sugar ratio. Phenotypic analysis revealed substantial variation, with coefficients of variation ranging from 28.84% to 53.86%, and high broad-sense heritability (87.90%-93.98%). Using 12,617,573 high-quality single-nucleotide polymorphisms, we identified 93 significant quantitative trait nucleotides associated with these traits. Transcriptomic data from the maize inbred line B73 highlighted six candidate genes (Zm00001d040189, Zm00001d032517, Zm00001d052399, Zm00001d028974, Zm00001d036971, and Zm00001d022316) with high expression during kernel development. Protein-protein interaction and coexpression network analyses suggested that these genes are involved in metabolic processes, cell communication, and carbohydrate metabolism. Haplotype analysis further revealed that the optimal haplotypes of the six candidate genes could increase the kernel sugar content without affecting the yield traits of maize. These findings advance our understanding of the genetic basis of sugar-related traits in maize and offer valuable molecular markers for future breeding programs.

Eleven QTLs controlling maize ESL were identified via high-resolution QTL mapping of 866 maize–teosinte RILs and three promising candidate genes for qESL1-1 were further screened through integrated RNA-seq and qRT-PCR. Ear shank length (ESL) represents a critical architectural trait in maize that significantly influences yield formation, kernel dehydration, and mechanical harvesting efficiency. To dissect the genetic architecture underlying ESL variation, we conducted a high-resolution quantitative trait locus (QTL) mapping using 866 maize–teosinte BC₂S₃ recombinant inbred lines genotyped with 19,838 single nucleotide polymorphism markers. Phenotypic evaluation across three environments revealed extensive ESL variation with values ranging from 9.9 to 18.7 cm. Correlation analysis demonstrated that ESL showed positive correlations with most agronomic traits but negative correlations with most yield-related traits, while having relatively limited effects on nutritional traits. Multiple QTL mapping identified 11 QTLs distributed across eight chromosomes, collectively explaining 35.8

Cd contamination poses a serious threat to maize production by inducing oxidative stress and disrupting vital physiological processes. This study systematically investigated the time-dependent dynamic responses of maize seedlings to Cd stress. Physiological assessments revealed that Cd stress triggered excessive accumulation of ROS. MDA levels in roots increased significantly at all time points, whereas shoots exhibited a delayed accumulation pattern. The activities of antioxidant enzymes (SOD, CAT, and POD) displayed distinct tissue- and time-specific responses. Transcriptomic profiling identified 8789 DEGs that exhibited sustained expression changes across stress durations.These DEGs were significantly enriched in pathways related to photosynthesis, secondary metabolism, and antioxidant defense. Metabolomic analyses detected 286, 158, and 371 DAMs at corresponding time points. Key metabolites, such as salicylic alcohol glucoside and coumaroylquinic acid, were strongly associated with oxidative stress regulation. Integrated transcriptome–metabolome analysis demonstrated that plant hormone signaling, together with the TCA cycle, glycerophospholipid metabolism, phenylpropanoid biosynthesis, and glutathione metabolism, coordinately contribute to Cd detoxification. This occurs by forming a multilayered defense network. These findings reveal the time-dependent adaptive strategies of maize under Cd stress and provide valuable insights for the development of Cd-tolerant maize cultivars.

Crude fat is an important nutritional component of maize kernels. However, the genetic mechanisms underlying crude fat content in maize kernels remain elusive. Previous studies used single-model genome-wide association studies (GWAS) with limited population sizes, which can result in false loci positives and hinder functional gene identification. Therefore, this study used a population consisting of 495 maize inbred lines, combined with 1.25 million single nucleotide polymorphisms (SNPs), and implemented GWAS using six models to identify quantitative trait nucleotides (QTNs) controlling crude fat content and to mine key genes. The results revealed a wide variation in crude fat content (0.62-16.03%) and broad-sense heritability (H2) (96.23%). In total, 744 significant QTNs were detected, with 147 co-located across different models, environments, and methods. Based on the 147 co-located QTNs, candidate genes were searched at 50 kb up-and down-stream intervals of each QTN. We finally screened eight candidate genes (GRMZM2G169089, GRMZM2G117935, GRMZM2G002075, GRMZM2G368838, GRMZM2G058496, GRMZM2G090669, GRMZM2G001241, and GRMZM2G333454) related to crude fat content that exhibited high expression levels during kernel development in maize inbred line B73. Notably, GRMZM2G169089, GRMZM2G117935, GRMZM2G002075, and GRMZM2G368838 are involved in the linoleic acid metabolic pathway, oil metabolism, kernel growth, and development in maize. Furthermore, co-expression network analysis revealed that the eight candidate genes strongly correlated with 30 known genes. Proteins encoded by candidate genes interact with other proteins and play an important role in oil content and oleic acid metabolism in maize kernels. The best haplotypes of candidate genes might increase crude fat content without decreasing maize yield. These results broaden the understanding of the genetic mechanism of crude fat content and facilitate marker-assisted selection for high-crude fat breeding programs for maize.

Hybridization has long been a crucial strategy for breeders aiming to develop high-yield crops vital for global food security. However, the exact molecular mechanisms driving heterosis (hybrid vigor) remain a topic of debate. Maize (Zea mays), which demonstrates pronounced heterosis, serves as an ideal model for studying this phenomenon. In our study, we carefully measured phenotypic changes in ear diameter, tracing its development from the inflorescence meristem (IM) to the floral meristem (FM) stages. Our findings revealed a complex progression: the hybrid's ear diameter followed an additive pattern during the IM and spikelet pair meristem (SPM) stages, shifted to incomplete dominance at the spikelet meristem (SM) stage, and ultimately displayed over-dominance at the FM stage. Notably, significant phenotypic changes occurred during the SM stage with gene expression primarily showing non-additive patterns. Gene Ontology (GO) enrichment analysis highlighted the role of cell redox homeostasis genes, which exhibited over-dominant expression in hybrids, as key contributors to heterosis. Furthermore, we identified a distinct gene expression category - dominant maternal or paternal gene expression in F1 hybrids (DMP) - characterized by exclusive expression in the hybrid and one parent, while remaining inactive in the other. This category of DMP genes plays a pivotal role in shaping the diverse gene expression patterns observed in hybrids, distinguishing them from their parental lines. In conclusion, the widespread occurrence of non-additive expression seems to enhance the efficiency of biological processes and energy distribution in hybrids, ultimately driving the manifestation of heterosis.

Maize is one of the main food crops in the world, and cultivating high-yield and high-quality maize varieties is of great significance in addressing food security issues. Leaves are crucial photosynthetic organs in maize, and leaf senescence can result in the degradation of chlorophyll. This, in turn, impacts photosynthetic activity and the accumulation of photosynthetic products. Delaying leaf senescence and increasing carbon assimilation can enhance grain yield and biomass production. The stay green of maize is an important trait closely related to yield, feed quality and resistance. Therefore, this study employed multi-generation joint analysis of major genes and a polygene model to investigate the genetic inheritance of stay green-related traits. Four populations (P1, P2, F1 and F2) were obtained by crossing T01 (stay green) × Xin3 (non-stay green) and T01 (stay green) × Mo17 (non-stay green) under two environments. Six stay green-related traits, including visual stay green (VSG), number of green leaves (GLNM), SPAD value of ear leaf at anthesis (SPADS), SPAD value of ear leaf at maturity (SPADM), absolute green leaf area (GLAD), grain yield per plant (GYP), displayed continuous variations with kurtosis and skewness values of absolute value less than 1 and distribution close to normal. They were characterized by typical inheritance of quantitative traits, with these traits demonstrating the transgressive segregation. The correlation analysis among the traits revealed that five stay green traits have a positive impact on yield. VSG, GLNM and SPADM in the two populations were regulated by the two major genes of additive effects plus additive-dominance polygene model with a major gene heritability varying from 89.03 to 95.95% in the F2 generation. GLAD in TMF2 was controlled by two major genes of equal-additive dominance effects with high heritability (93.47%). However, in TXF2, GLAD was regulated by two major genes of additive-dominance interaction effects plus additive-dominance polygene model. These results provide important genetic information for breeding, which could guide the improvement of stay green-related traits. They also lay a foundation for quantitative trait loci mapping of the stay stay-green traits in maize.

Maize (Zea mays) cultivation is strongly affected by both abiotic and biotic stress, leading to reduced growth and productivity. It has recently become clear that regulators of plant stress responses, including the phytohormones abscisic acid (ABA), ethylene (ET), and jasmonic acid (JA), together with reactive oxygen species (ROS), shape plant growth and development. Beyond their well established functions in stress responses, these molecules play crucial roles in balancing growth and defense, which must be finely tuned to achieve high yields in crops while maintaining some level of defense. In this review, we provide an in-depth analysis of recent research on the developmental functions of stress regulators, focusing specifically on maize. By unraveling the contributions of these regulators to maize development, we present new avenues for enhancing maize cultivation and growth while highlighting the potential risks associated with manipulating stress regulators to enhance grain yields in the face of environmental challenges.

The experiment was to investigate the effect of different planting densities on the yield and quality of MT-8 in F8 generation of distant hybrid of maize and teosinte. MT-8 was used as the research material, and six planting densities of 52 500, 60 000, 67 500, 75 000, 82 500, and 90 000 plants/hm² were set up. The results showed that the both fresh weight and dry weight of MT-8 increased with the increase of planting density, and reached the maximum value when planting density was 75 000 plants/hm². At a planting density of 75 000 plants /hm2, MT-8 had higher nutrient yield and higher feeding value, and the nutrient type was NC. The study indicates that the suitable planting density of MT-8 is 75 000 plants /hm2.

Phenolamides are important secondary metabolites in plant species. They play important roles in plant defense responses against pathogens and insect herbivores, protection against UV irradiation and floral induction and development. However, the accumulation and variation in phenolamides content in diverse maize lines and the genes responsible for their biosynthesis remain largely unknown. Here, we combined genetic mapping, protein regulatory network and bioinformatics analysis to further enhance the understanding of maize phenolamides biosynthesis. Sixteen phenolamides were identified in multiple populations, and they were all significantly correlated with one or several of 19 phenotypic traits. By linkage mapping, 58, 58, 39 and 67 QTLs, with an average of 3.9, 3.6, 3.6 and 4.2 QTLs for each trait were mapped in BBE1, BBE2, ZYE1 and ZYE2, explaining 9.47%, 10.78%, 9.51% and 11.40% phenotypic variation for each QTL on average, respectively. By GWAS, 39 and 36 significant loci were detected in two different environments, 3.3 and 2.8 loci for each trait, explaining 10.00% and 9.97% phenotypic variation for each locus on average, respectively. Totally, 58 unique candidate genes were identified, 31% of them encoding enzymes involved in amine and derivative metabolic processes. Gene Ontology term analysis of the 358 protein-protein interrelated genes revealed significant enrichment in terms relating to cellular nitrogen metabolism, amine metabolism. GRMZM2G066142, GRMZM2G066049, GRMZM2G165390 and GRMZM2G159587 were further validated involvement in phenolamides biosynthesis. Our results provide insights into the genetic basis of phenolamides biosynthesis in maize kernels, understanding phenolamides biosynthesis and its nutritional content and ability to withstand biotic and abiotic stress.

Here, we propose a method to convert the organic nitrogen in maize kernels into ammonia in solution and then chlorinate it to prepare monochloride salts, which can form an oxidatively coupled blue-green mixture with sodium salicylate and sodium dichloroisocyanurate. The concentration of ammonium ions in the blue-green mixture can then be determined in the solution, and finally the protein content in maize kernels can be calculated from the nitrogen content.

Maize has become one of the most widely grown grains in the world, and the stay-green mutant allows these plants to maintain their green leaves and photosynthetic potential for longer following anthesis than in non-mutated plants. As a result, stay-green plants have a higher production rate than non-stay-green varieties due to their prolonged grain-filling period. In this study, the candidate genes related to the visual stay-green at the maturation stage of maize were investigated. The F2 population was derived from the T01 (stay-green) and the Xin3 (non-stay-green) cross. Two bulked segregant analysis pools were constructed. According to the method of combining ED (Euclidean distance), Ridit (relative to an identified distribution unit), SmoothG, and SNP algorithms, a region containing 778 genes on chromosome 9 was recognized as the candidate region associated with the visual stay-green in maize. A total of eight modules were identified using WGCNA (weighted correlation network analysis), of which green, brown, pink, and salmon modules were significantly correlated with visual stay-green. BSA, combined with the annotation function, discovered 7 potential candidate genes, while WGCNA discovered 11 stay-green potential candidate genes. The candidate range was further reduced due through association analysis of BSA-seq and RNA-seq. We identified Zm00001eb378880, Zm00001eb383680, and Zm00001eb384100 to be the most likely candidate genes. Our results provide valuable insights into this new germplasm resource with reference to increasing the yield for maize.

Three densities（60 000,75 000,90 000 plants/ha）,three nitrogen application levels（150,225,300 kg/ha）and two chemical control treatments（no chemical control,chemical control）were set,and combined into seven cultivation patterns,including T1（high density,high nitrogen and chemical control）,T2（high density,medium nitrogen and chemical control）,T3（high density,low nitrogen and chemical control）,T4（medium density,high nitrogen and chemical control）,T5（medium density,medium nitrogen and chemical control）,T6（medium density,low nitrogen and chemical control）and CK（low density,high nitrogen and no chemical control）. The effects of different cultivation patterns on the yield and lodging resistance of summer maize varieties Zhengdan 958 and Xiangnongyu 27 were studied,so as to clarify the suitable cultivation pattern for summer maize in Dongting Lake area. The results showed that the yield of Zhengdan 958 was higher than that of Xiangnongyu 27 on the whole,and the yields of the two varieties in2 a were higher in T1 and T2 patterns,and the difference between the two treatments was not significant.Compared with CK,the plant height and ear height of each pattern significantly decreased,and the stem diameter roughly decreased. There were significant differences in the number of airborne layers among the patterns,the T1 and T2 patterns were more for Zhengdan 958,and the T4 and T5 patterns were more for Xiangnongyu 27. The change rules of stem puncture strength and compressive strength were not obvious,but showed differences between varieties and between years. No plant lodging and folding occurred in 2 a tests. In conclusion,by rational allocation of nitrogen application rate,planting density and chemical control measures,lodging resistance and high yield of summer maize could be achieved.The T2 pattern is the ideal cultivation mode for summer maize in Dongting Lake area under the present experimental conditions.

为揭示玉米雄性不育系的生理生化特征,以玉米细胞质雄性不育系S37-2、保持系B37-2为试验材料,对其主要表型性状进行调查,测定不同发育期叶片中的可溶性蛋白、游离脯氨酸、可溶性糖、可溶性淀粉和丙二醛(MDA)含量,以及过氧化氢酶(CAT)、超氧化物歧化酶(SOD)、过氧化物酶(POD)活性.结果表明,S37-2花药形状瘦小萎缩,饱满度差,花药的长度、横截面直径均显著(P<0.05)低于B37-2.S37-2在抽雄期与散粉期叶片中的可溶性蛋白、游离脯氨酸和可溶性糖含量显著(P<0.05)高于B37-2,在各个时期叶片中的CAT活性和SOD活性均显著(P<0.05)低于B37-2.综上推测,S37-2叶片中的可溶性蛋白、游离脯氨酸和可溶性糖运输受阻,SOD和CAT活性低,是导致S37-2不育的重要原因.

[目的]探究萌发玉米在不同光照条件下营养成分和抗氧化酶活性的变化,为优化玉米萌发条件及萌发玉米产品的研发提供参考依据.[方法]以湘荟玉1号玉米为试验材料,测定3个光照处理(24h光照、12h黑暗+12 h光照和24h黑暗)、玉米不同萌发天数(0、1、3和5d)的营养成分含量及超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和过氧化物酶(POD)活性,并测定萌发1、3和5d的胚根长和胚芽长,计算发芽率和活力指数,分析玉米萌发指标与营养成分含量和酶活性的相关性.[结果]随萌发天数的延长,玉米中清蛋白、球蛋白、赖氨酸和还原糖含量及3种酶活性显著增加(P<0.05,下同),总糖和淀粉含量显著降低.与未萌发籽粒相比,萌发5d时12h黑暗+12 h光照处理清蛋白含量显著增加46.11%;除球蛋白含量外,12 h黑暗+12 h光照处理的各营养物质含量及4个萌发指标在萌发第5d均显著高于其他2个处理.24 h光照处理POD和SOD活性显著高于其他2个处理,而24h黑暗处理的CAT活性在3个处理中增加最显著;与萌发1d相比,24 h黑暗、12h黑暗+12 h光照和24h光照处理的发芽率在萌发第5d分别显著增加497.64%、137.69%和263.48%;4个萌发指标均与清蛋白、球蛋白、还原糖和赖氨酸含量呈极显著(P<0.01)或显著正相关.[结论]12h黑暗+12 h光照条件有利于玉米籽粒的萌发及营养物质的积累,植物通过激活酶活系统以清除因光照过多或过少产生的毒害物质.

Seed size is an important factor contributing to maize yield, but its molecular mechanism remains unclear. The seed coat, which serves as one of the three components of the maize grain, determines seed size to a certain extent. The seed coat also shares the maternal genotype and is an ideal material for studying heterosis. In this study, the self-pollinated seeds of the maize hybrid Yudan888 and its parental lines were continuously collected from 0 day after pollination (DAP) to 15 DAP for phenotyping, cytological observation and RNA-seq. The phenotypic data showed that 3 DAP and 8 DAP are the best time points to study maize seed coat heterosis. Cytological observations indicated that maize seed coat heterosis might be the result of the coordination between cell number and cell size. Furthermore, the RNA-seq results showed that the nonadditive genes changed significantly between 3 and 8 DAP. However, the number of genes expressed additively was not significantly different. Our findings suggest that seed coat heterosis in hybrid is the result of nonadditive expression caused by dynamic changes in genes at different time points during seed expansion and seed coat development. Gene Ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment indicated that genes related to DNA replication, cell cycle regulation, circadian rhythms and metabolite accumulation contributed significantly to hybrid seed coat heterosis. Maize seed coat phenotyping allowed us to infer that 3 DAP and 8 DAP are important time points in the study of seed coat heterosis. Our findings provide evidence for genes involved in DNA replication, cell cycle regulation, circadian rhythms and metabolite accumulation in hybrid with high or low parental expression as major contributors to hybrid seed coat heterosis.

【Objective】The effects of light intensity on seeds germination and physiological index of maize were studied through experiments in order to determine the optimum light for maize germination.【Method】The influence of different germination time（1, 3, 5 days） and illumination time（light for 24 hours, light for 12 hours and dark for 24 hours） on the growth and quality of xiangnongyu 27 were analyzed in the present study, and the germination rate, radicle and germ length were determined.At the same time, the albumin, globulin, gliadin, glutenin, total protein, reducing sugar, total sugar, amylopectin, amylose, total starch, lysine, catalase（CAT）, superoxide dismutase（SOD） and peroxidase（POD） of maize were measured, and the correlation between growth and quality indexes and antioxidant enzyme activity was analyzed.【Result】The germination rate, radicle and germ length of maize seeds increased with the extension of light time.The contents of glutenin, gliadin, total protein, total sugar, amylose, total starch and pod in maize seeds decreased, and the content was the lowest under 24 hours light treatment.The contents of albumin, globulin, reducing sugar, lysine, CAT and SOD showed an upward trend, and the content was the highest under 24 hours light treatment.For the same germination days, the amylopectin content and the extension of light time did not show an obvious law.Correlation analysis showed that under different light treatments, CAT, SOD and POD were significantly correlated with starch components, and germination rate, radicle length and germ length were significantly/extremely significantly positively correlated with albumin, globulin, reducing sugar and lysine.【Conclusion】24 hours light treatment can promote the germination of corn seeds, significantly increase the content of quality indexes such as albumin, globulin, reducing sugar and lysine, and the antioxidant activity of cat and SOD enzymes, which provides data support and theoretical reference for optimizing corn germination methods and developing germinated corn food.

为了探究玉米在萌发期生长状态和营养成分的变化规律,本实验以湘荟玉1号(普通玉米)、湘农甜玉4号(甜玉米)和湘农白糯2号(糯玉米)为材料,测定不同萌发时间的营养成分含量,并统计萌发期玉米的发芽率、胚根长和胚芽长.结果表明:普通玉米生长状态最好,萌发速度最快;在萌发期间,3个玉米的清蛋白、球蛋白、还原糖和赖氨酸含量均呈上升变化趋势,增加范围分别为5.33％～103.26％、1.92％～125.00％、10.40％～529.59％和12.50％～100.00％,其中糯玉米是富集营养物质能力强的优秀品种;相关性分析结果发现玉米的生长状态与营养物质密切相关.

为探究不同品种玉米苗期对镉胁迫的响应差异,筛选出耐镉性较强的品种,选用4 个玉米杂交种(京农科728、郑单958、正大999、豫单9953),通过水培的方法进行镉胁迫(6 mg/L CdCl2·2.5H2O)处理,在镉胁迫3、6、9、12 d后对4个玉米品种苗期的生长指标和生理指标进行检测分析,并采用主成分分析和隶属函数法进行耐镉性综合评价.结果表明:镉胁迫后4 个品种幼苗的根长、株高、地上部干质量、地上部鲜质量、地下部干质量、地下部鲜质量和总叶绿素含量整体低于对照(蒸馏水处理),豫单9953 在整个胁迫过程中叶片和根部的POD活性以及MDA含量高于对照组;镉胁迫下,与其他品种相比,豫单9953 的株高、根长和干质量下降幅度较大,但其鲜质量受影响较小,且其叶片MDA含量增加幅度小,POD 活性强.耐镉性综合评价结果显示,豫单9953、京农科728、正大999、郑单958 的耐镉性依次减弱,豫单9953 可作为耐镉性品种培育.

The contamination of agricultural soil with cadmium (Cd), a heavy metal, poses a significant environmental challenge, affecting crop growth, development, and human health. Previous studies have established the pivotal role of the ZmHMA3 gene, a P-type ATPase heavy metal transporter, in determining variable Cd accumulation in maize grains among 513 inbred lines. To decipher the molecular mechanism underlying mutation-induced phenotypic differences mediated by ZmHMA3, we conducted a quantitative tandem mass tag (TMT)-based proteomic analysis of immature maize kernels. This analysis aimed to identify differentially expressed proteins (DEPs) in wild-type B73 and ZmHMA3 null mutant under Cd stress. The findings demonstrated that ZmHMA3 accumulated higher levels of Cd compared to B73 when exposed to varying Cd concentrations in the soil. In comparison to soil with a low Cd concentration, B73 and ZmHMA3 exhibited 75 and 142 DEPs, respectively, with 24 common DEPs shared between them. ZmHMA3 showed a higher induction of upregulated genes related to Cd stress than B73. Amino sugar and nucleotide sugar metabolism was specifically enriched in B73, while phenylpropanoid biosynthesis, nitrogen metabolism, and glyoxylate and dicarboxylate metabolism appeared to play a more significant role in ZmHMA3. This study provides proteomics insights into unraveling the molecular mechanism underlying the differences in Cd accumulation in maize kernels.