Genome-wide association studies (GWAS) have emerged as a powerful tool for unraveling intricate genotype-phenotype association across various species. Maize (
L.), renowned for its extensive genetic ...diversity and rapid linkage disequilibrium (LD), stands as an exemplary candidate for GWAS. In maize, GWAS has made significant advancements by pinpointing numerous genetic loci and potential genes associated with complex traits, including responses to both abiotic and biotic stress. These discoveries hold the promise of enhancing adaptability and yield through effective breeding strategies. Nevertheless, the impact of environmental stress on crop growth and yield is evident in various agronomic traits. Therefore, understanding the complex genetic basis of these traits becomes paramount. This review delves into current and future prospectives aimed at yield, quality, and environmental stress resilience in maize and also addresses the challenges encountered during genomic selection and molecular breeding, all facilitated by the utilization of GWAS. Furthermore, the integration of omics, including genomics, transcriptomics, proteomics, metabolomics, epigenomics, and phenomics has enriched our understanding of intricate traits in maize, thereby enhancing environmental stress tolerance and boosting maize production. Collectively, these insights not only advance our understanding of the genetic mechanism regulating complex traits but also propel the utilization of marker-assisted selection in maize molecular breeding programs, where GWAS plays a pivotal role. Therefore, GWAS provides robust support for delving into the genetic mechanism underlying complex traits in maize and enhancing breeding strategies.
Phosphorus (P) is a crucial macronutrient for plant growth and development, and low-Pi stress poses a significant limitation to maize production. While the role of the SPX domain in encoding proteins ...involved in phosphate (Pi) homeostasis and signaling transduction has been extensively studied in other model plants, the molecular and functional characteristics of the SPX gene family members in maize remain largely unexplored. In this study, we identified six SPX members, and the phylogenetic analysis of ZmSPX s revealed a close relationship with SPX genes in rice. The promoter regions of ZmSPX s were abundant in biotic and abiotic stress-related elements, particularly associated with various hormone signaling pathways, indicating potential intersections between Pi signaling and hormone signaling pathways. Additionally, ZmSPX s displayed tissue-specific expression patterns, with significant and differential induction in anthers and roots, and were localized to the nucleus and cytoplasm. The interaction between ZmSPX s and ZmPHR s was established via yeast two-hybrid assays. Furthermore, overexpression of ZmSPX1 enhanced root sensitivity to Pi deficiency and high-Pi conditions in Arabidopsis thaliana . Phenotypic identification of the maize transgenic lines demonstrated the negative regulatory effect on the P concentration of stems and leaves as well as yield. Notably, polymorphic sites including 34 single-nucleotide polymorphisms (SNPs) and seven insertions/deletions (InDels) in ZmSPX1 were significantly associated with 16 traits of low-Pi tolerance index. Furthermore, significant sites were classified into five haplotypes, and haplotype5 can enhance biomass production by promoting root development. Taken together, our results suggested that ZmSPX family members possibly play a pivotal role in Pi stress signaling in plants by interacting with ZmPHR s. Significantly, ZmSPX1 was involved in the Pi-deficiency response verified in transgenic Arabidopsis and can affect the Pi concentration of maize tissues and yield. This work lays the groundwork for deeper exploration of the maize SPX family and could inform the development of maize varieties with improved Pi efficiency.
Phosphorus deficiency is one of the major factors limiting plant growth and grain yield. Improving plant tolerance to Pi deficiency through genetic mechanism is an important source to increase grain ...yield. In this study, bioinformatics analysis, expression, and natural variation in
ZmNAC134
gene with low Pi tolerant traits were analyzed under low Pi conditions. A total of 177 diverse heterotic groups of maize inbreds were used to identify the nucleotide diversity and alleles of
ZmNAC134
, which plays a vital role in the regulation of root architecture in response to Pi deficiency evolutionary results showed that
ZmNAC134
has 3 homologous genes and these genes have one exon and conserved domain. The phenotypic traits showed significant difference for each of the 22 traits under deficient and sufficient Pi conditions. A total of 27 SNPs were identified in the coding region of
ZmNAC134
and no InDels among 177 inbred lines. Among 27 SNPs, a total of 8 sites were highly significantly associated with multiple traits of low Pi tolerant trait index at − log10
P
= 3.43. Although, 7 sites under Pi normal and 9 sites under Pi deficient conditions, of which four synonymous sites (position S24, S82, S164, and S1037) were associated with diverse number of traits in low Pi and normal Pi conditions and LD was not tight among these sites. Furthermore, the expression pattern was compared between Pi tolerant 178 and Pi sensitive 9782 inbred lines.
ZmNAC134
was highly up-regulated in the roots and leaves of Pi tolerant 178 inbred line at 3 days, 7 days, and 9 days in roots and 7 days and 12 days in leaves while down-regulated in roots and leaves of Pi sensitive 9782 inbred line. In addition, protein encoded by
ZmNAC134
was located in both nucleus and cytoplasm. Our findings provide the new insight of
ZmNAC134
gene involved in low Pi stress and responsible against low Pi condition and the significant association of polymorphic loci with traits could be helpful to find out the molecular marker for genetic resources for further molecular maize breeding program.
Nutrient restrictions and large-scale emergence of diseases are threatening the maize production. Recent findings demonstrated that there is a certain synergistic interaction between nutrition and ...diseases pathways in model plants, however there are few studies on the synergistic genes of nutrients and diseases in maize. Thus, the transcriptome data of nitrogen (N) and phosphorus (P) nutrients and diseases treatments in maize, rice, wheat and Arabidopsis thaliana were collected in this study, and four and 22 weighted co-expression modules were obtained by using Weighted Gene Co-expression Network Analysis (WGCNA) in leaf and root tissues, respectively. With a total of 5252 genes, MFUZZ cluster analysis screened 26 clusters with the same expression trend under nutrition and disease treatments. In the meantime, 1427 genes and 22 specific consensus quantitative trait loci (scQTLs) loci were identified by meta-QTL analysis of nitrogen and phosphorus nutrition and disease stress in maize. Combined with the results of cluster analysis and scQTLs, a total of 195 consistent genes were screened, of which six genes were shown to synergistically respond to nutrition and disease both in roots and leaves. Moreover, the six candidate genes were found in scQTLs associated with gray leaf spot (GLS) and corn leaf blight (CLB). In addition, subcellular localization and bioinformatics analysis of the six candidate genes revealed that they were primarily expressed in endoplasmic reticulum, mitochondria, nucleus and plasma membrane, and were involved in defense and stress, MeJA and abscisic acid response pathways. The fluorescence quantitative PCR confirmed their responsiveness to nitrogen and phosphorus nutrition as well as GLS treatments. Taken together, findings of this study indicated that the nutrition and disease have a significant synergistic response in maize.
A previous metabolomic and genome-wide association analysis of maize screened a glucose-6-phosphate 1-epimerase (
ZmG6PE
) gene, which responds to low-phosphorus (LP) stress and regulates yield in ...maize’s recombinant inbred lines (RILs). However, the relationship of
ZmG6PE
with phosphorus and yield remained elusive. This study aimed to elucidate the underlying response mechanism of the
ZmG6PE
gene to LP stress and its consequential impact on maize yield. The analysis indicated that ZmG6PE required the Aldose_epim conserved domain to maintain enzyme activity and localized in the nucleus and cell membrane. The
zmg6pe
mutants showed decreased biomass and sugar contents but had increased starch content in leaves under LP stress conditions. Combined transcriptome and metabolome analysis showed that LP stress activated plant immune regulation in response to the LP stress through carbon metabolism, amino acid metabolism, and fatty acid metabolism. Notably, LP stress significantly reduced the synthesis of glucose-1-phosphate, mannose-6-phosphate, and β-alanine-related metabolites and changed the expression of related genes.
ZmG6PE
regulates LP stress by mediating the expression of
ZmSPX6
and
ZmPHT1.13
. Overall, this study revealed that
ZmG6PE
affected the number of grains per ear, ear thickness, and ear weight under LP stress, indicating that
ZmG6PE
participates in the phosphate signaling pathway and affects maize yield-related traits through balancing carbohydrates homeostasis.
Phosphorus (P) is an essential macroelement supporting maize productivity and low-P stress is a limiting factor of maize growth and yield. Improving maize plant tolerance to low P through molecular ...breeding is an effective alternative to increase crop productivity. In this study, a total of 111 diverse maize inbred lines were used to identify the favorable alleles and nucleotide diversity of candidate ZmNAC9, which plays an important role in response to low P and regulation in root architecture. A significant difference was found under low- and sufficient-P conditions for each of the 22 seedling traits, and a total of 41 polymorphic sites including 32 single nucleotide polymorphisms (SNPs) and 9 insertion and deletions (InDels) were detected in ZmNAC9 among 111 inbred lines. Among the 41 polymorphic studied sites, a total of 39 polymorphic sites were associated with 20 traits except for the dry weight of shoots and forks, of which six sites were highly significantly associated with a diverse number of low-P tolerant root trait index values by using a mixed linear model (MLM) at −log10 P = 3.61. In addition, 29 polymorphic sites under P-sufficient and 32 polymorphic sites under P-deficient conditions were significantly associated with a diverse number of seedling traits, of which five polymorphic sites (position S327, S513, S514, S520, and S827) were strongly significantly associated with multiple seedling traits under low-P and normal-P conditions. Among highly significant sites, most of the sites were associated with root traits under low-P, normal-P, and low-P trait index values. Linkage disequilibrium (LD) was strong at (r2 > 1.0) in 111 inbred lines. Furthermore, the effect of five significant sites was verified for haplotypes in 111 lines and the favorable allele S520 showed a positive effect on the dry weight of roots under the low-P condition. Furthermore, the expression pattern confirmed that ZmNAC9 was highly induced by low P in the roots of the P-tolerant 178 inbred line. Moreover, the subcellular localization of ZmNAC9 encoded by protein was located in the cytoplasm and nucleus. Haplotypes carrying more favorable alleles exhibited superior effects on phenotypic variation and could be helpful in developing molecular markers in maize molecular breeding programs. Taken together, the finding of this study might lead to further functions of ZmNAC9 and genes that might be involved in responses to low-P stress in maize.
Maize is one of the most important food and feed crops in China due to the high demand for its use by both humans and animals. The Huang-Huai-Hai region is a major maize cultivation area in China, ...and the special cropping rotation system of wheat and maize requires a suitable reproductive period for maize. The AUX/IAA and ARF transcription factors are two key genes that regulate auxin signals in plants, which play an important role during the process of auxin regulation in plant growth and development. In this study, we obtained two overexpressed lines of ZmIAA29 belonging to the AUX/IAA transcription factor family. Compared with the Wide type, the overexpressed strains of ZmIAA29 were significantly regulated in maize during the flowering time and had increased ear weight. Moreover, ZmIAA29 was assayed via the yeast two-hybrid and BiLUC systems for interaction, and the results showed that ZmIAA29 interacted with several ZmARF transcription factors. Furthermore, RNA-seq and DAP-seq analysis revealed that ZmIAA29 regulates maize growth and development by influencing pathways such as those for plant signal transduction and the key genes related to maize flowering. Taken together, our results suggest that ZmIAA29 plays a key role in the development of maize flowering. This study provides new insight for better understanding the combined regulation of the AUX/IAA and ARF transcription factors during flowering time in maize.
Subtrochanteric fractures treated with dynamic condylar screw Sahito, Badaruddin; Khaskheli, Javed Hussain; Kumar, Dileep ...
Annals of Abbasi Shaheed Hospital and Karachi Medical & Dental College,
02/2022, Letnik:
27, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Objectives: To assess the functional outcome of dynamic condylar screws to treat subtrochanteric fractures in adult patients.
Methods: The prospective descriptive study was conducted at the ...department of orthopedic surgery, Dr. Ruth KM Pfau civil hospital Karachi, Pakistan, from March 2016 to October 2019. A total of 47 patients of 18 to 60 years of either gender with subtrochanteric fractures treated with dynamic condylar screw were included in the study. After consent and counseling, patients were operated on by a consultant orthopedic surgeon and fixed with a dynamic condylar screw. Postoperatively patients were regularly followed at 2nd, 6th, 12th, 16th, 20th weeks, and onwards monthly for at least one year. Functional outcomes such as infection, union, failure of fixation were observed in all patients. SPSS software version 23 was used to analyze data. Mean and SD was reported for numeric variables, whereas frequency and percentage were reported for categorical variables. A Chi-square test was used to assess the association between variables.
Results: The mean age was estimated as 37.53±12.31 years. Most of the patients were male (74.5%), and 25.5% were females. About 27 patients had a fracture on the right side (57.4%) and 20 on the left side (42.6%). Out 47 cases, 3 were lost to follow, 33 patients showed excellent outcomes, 6 cases had a good outcome, 3 cases had fair outcomes, and 2 cases had poor functional outcomes. During the follow-up, 42 cases showed union, 3 lost to follow-up, 1 died, and 1 patient had implant break. About 2 patients had infections in post- operative duration because of fracture.
Conclusion: Subtrochanteric femur fractures are challenging to operate, especially in our society where extensive trauma becomes more frequent. Dynamic condylar screws showed overall acceptable results. It is simple, locally made, readily available, and cheap, with almost the same result as other implants around proximal femur fractures.
Mercury (Hg) pollution not only poses a threat to the environment but also adversely affects the growth and development of plants, with potential repercussions for animals and humans through ...bioaccumulation in the food chain. Maize, a crucial source of food, industrial materials, and livestock feed, requires special attention in understanding the genetic factors influencing mercury accumulation. Developing maize varieties with low mercury accumulation is vital for both maize production and human health. In this study, a comprehensive genome-wide association study (GWAS) was conducted using an enlarged SNP panel comprising 1.25 million single nucleotide polymorphisms (SNPs) in 230 maize inbred lines across three environments. The analysis identified 111 significant SNPs within 78 quantitative trait loci (QTL), involving 169 candidate genes under the Q model. Compared to the previous study, the increased marker density and optimized statistical model led to the discovery of 74 additional QTL, demonstrating improved statistical power. Gene ontology (GO) enrichment analysis revealed that most genes participate in arsenate reduction and stress responses. Notably,
, which has been reported in previous studies, is associated with the significant SNP chr6.S_155668107 in axis tissue. It encodes a cysteine proteinase inhibitor, implying its potential role in mitigating mercury toxicity by inhibiting cysteine. Haplotype analyses provided further insights, indicating that lines carrying hap3 exhibited the lowest mercury content compared to other haplotypes. In summary, our study significantly enhances the statistical power of GWAS, identifying additional genes related to mercury accumulation and metabolism. These findings offer valuable insights into unraveling the genetic basis of mercury content in maize and contribute to the development of maize varieties with low mercury accumulation.
Objective: To determine the functional outcome of posterior lip acetabular fracture and hip dislocation fixed with reconstruction plate. Study Design: Descriptive Case Series study. Setting: ...Department of Orthopaedic, Dr Ruth K. M. Pfau Civil Hospital Karachi. Period: August 2014 to December 2020. Material & Methods: 36 patients were included in the study. Age between18 years to 60 years. All patients fixed with reconstruction plate. Harris hip score assessed at follow up till 12 months. Harris hip score above 90 was considered as excellent, between 70–89 as good and below 70 as poor. Results: The mean age of the patients was 43.67 ±11.56 years. Majority of the patients were males (n=29, 80.6%). Good functional outcome was found in (n=15, 41.7%) of the patients, excellent in 8 (22.2%) and poor in 13 (36.1%) patients. Satisfactory outcome was found in 23 (63.9%) patients. A significant association of satisfactory outcome was found with age (p-value <0.001). Avascular necrosis 7, infection 5 and arthritis in 6 patients noted. One patient had associated sciatic nerve palsy, three had head of femur fracture and 1 with ipsilateral midshaft femur fracture. Conclusion: For posterior hip dislocation with lip fracture we suggest emergency reduction and timely fixation of posterior lip fracture can improve the clinical outcome of patient and even complications happen in future it preserve the bone stock for the future arthroplasty procedure.
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