Key hormonal components regulate agronomically important traits in barley

Marek Marzec is supported by scholarships funded by the Ministry of Science and Higher Education (424/STYP/10/2015 and DN/MOB/245/IV/2015). Ahmad M. Alqudah supported by Leibniz Institute of Plant Genetics and Crop Plant Research (IPK).The development and growth of plant organs is regulated by phytohormones, which constitute an important area of plant science. The last decade has seen a rapid increase in the unravelling of the pathways by which phytohormones exert their influence. Phytohormones function as signalling molecules that interact through a complex network to control development traits. They integrate metabolic and developmental events and regulate plant responses to biotic and abiotic stress factors. As such, they influence the yield and quality of crops. Recent studies on barley have emphasised the importance of phytohormones in promoting agronomically important traits such as tillering, plant height, leaf blade area and spike/spikelet development. Understanding the mechanisms of how phytohormones interact may help to modify barley architecture and thereby improve its adaptation and yield. To achieve this goal, extensive functional validation analyses are necessary to better understand the complex dynamics of phytohormone interactions and phytohormone networks that underlie the biological processes. The present review summarises the current knowledge on the crosstalk between phytohormones and their roles in barley development. Furthermore, an overview of how phytohormone modulation may help to improve barley plant architecture is also provided.MNiS

Insight into the genetic contribution of maximum yield potential, spikelet development and abortion in barley

Societal Impact Statement To feed the world's ever‐increasing population, new genetic approaches are required. Increasing the number of living spikelets is one promising way to improve grain yield. This, in turn, increases the number of spikelets per plant, thereby increasing the total yield. We present the first evidence for genetic control of alive spikelets in barley. Discovering natural variation as well as genomic regions associated with these traits will serve as a benchmark in future breeding for improving grain yield. Summary The primary goal of most breeding programmes is to increase grain yield. However, one of the many methods for raising yield that is yet to be fully investigated is increasing the number of spikelets by minimising spikelet abortion. Spikelet abortion dramatically increases during the late reproductive phase, but the molecular and genetic mechanisms remain unknown. Here, we employed a phenotyping approach in which developed and undeveloped spikelets were detected and counted during spike development and their maximum yield potential (MYP) was investigated. We studied 20 agronomic and spikelet‐related traits using a set of 184 diverse spring barley accessions under field conditions. By employing a set of >125K  SNPs, GWAS was conducted. Our analysis revealed 26 genetic clusters associated with MYP and the number of developed and undeveloped spikelets. Most of the significant associated genomic regions were co‐located near the candidate genes of phytohormones such as ABA, auxin, and cytokinin suggesting the importance of phytohormones in keeping spikelets alive, their development, and MYP. Our findings point to a potential link between jasmonic acid and the MYP, development and abortion of spikelets. We further provide genetic evidence that sugar‐related genes and sucrose have the potential to regulate MYP, spikelet development and spikelet survival. Our findings can be used for marker‐assisted breeding and as a resource for future molecular and genetic validation. Collectively, we propose a new genetic network linking spikelet‐related traits to grain yield determinants

GWAS: Fast-forwarding gene identification and characterization in temperate Cereals: lessons from Barley – A review

Understanding the genetic complexity of traits is an important objective of small grain temperate cereals yield and adaptation improvements. Bi-parental quantitative trait loci (QTL) linkage mapping is a pow- erful method to identify genetic regions that co-segregate in the trait of interest within the research pop- ulation. However, recently, association or linkage disequilibrium (LD) mapping using a genome-wide association study (GWAS) became an approach for unraveling the molecular genetic basis underlying the natural phenotypic variation. Many causative allele(s)/loci have been identified using the power of this approach which had not been detected in QTL mapping populations. In barley (Hordeum vulgare L.), GWAS has been successfully applied to define the causative allele(s)/loci which can be used in the breeding crop for adaptation and yield improvement. This promising approach represents a tremendous step forward in genetic analysis and undoubtedly proved it is a valuable tool in the identification of can- didate genes. In this review, we describe the recently used approach for genetic analyses (linkage map- ping or association mapping), and then provide the basic genetic and statistical concepts of GWAS, and subsequently highlight the genetic discoveries using GWAS. The review explained how the candidate gene(s) can be detected using state-of-art bioinformatic tools

Yield Potential Evaluation in Chickpea Genotypes under Late Terminal Drought in Relation to the Length of Reproductive Stage

Chickpea grown in the semiarid Mediterranean environments of West Asia and North Africa may experience an extended late-drought stress. The objective of this experiment was to evaluate seed dry weight accumulation, reproductive growth duration, and seed yield in five chickpea genotypes in order to identify those under drought stress. Chickpea plants were exposed to two irrigation treatments (from flowering to seed physiological maturity): 1) Irrigation; 2) non-irrigation (rainfed) treatment. Seed dry weight and moisture content, seed yield and yield components, and reproductive growth duration [as defined from flowering to physiological maturity (yellow pods)] were measured. Seeds from plants grown under non-irrigation (rainfed) treatment reached their maximum dry weight and minimum seed moisture content earlier than those from plants grown under irrigation treatment, indicating that chickpea had shorter reproductive growth duration and faster maturity under late-terminal drought (rainfed). The non-irrigation treatment decreased seed yield by 49-54% as compared with the irrigation, except for Flip 97-99 (10% reduction only). Seed yield was positively correlated with reproductive growth duration. The genotype DZ 10-11 had the highest reproductive growth duration and seed yield under irrigation. Late drought stress (non-irrigation) was detrimental to all genotypes. To maximize seed yield of chickpea, late-terminal drought stress should be avoided

Genetic dissection of grain architecture-related traits in a winter wheat population

Background: The future productivity of wheat (T. aestivum L.) as the most grown crop worldwide is of utmost importance for global food security. Thousand kernel weight (TKW) in wheat is closely associated with grain architecture-related traits, e.g. kernel length (KL), kernel width (KW), kernel area (KA), kernel diameter ratio (KDR), and factor form density (FFD). Discovering the genetic architecture of natural variation in these traits, identifying QTL and candidate genes are the main aims of this study. Therefore, grain architecture-related traits in 261 worldwide winter accessions over three field-year experiments were evaluated. Results: Genome-wide association analysis using 90K SNP array in FarmCPU model revealed several interesting genomic regions including 17 significant SNPs passing false discovery rate threshold and strongly associated with the studied traits. Four of associated SNPs were physically located inside candidate genes within LD interval e.g. BobWhite_c5872_589 (602,710,399 bp) found to be inside TraesCS6A01G383800 (602,699,767–602,711,726 bp). Further analysis reveals the four novel candidate genes potentially involved in more than one grain architecture-related traits with a pleiotropic effects e.g. TraesCS6A01G383800 gene on 6A encoding oxidoreductase activity was associated with TKW and KA. The allelic variation at the associated SNPs showed significant differences betweeen the accessions carying the wild and mutated alleles e.g. accessions carying C allele of BobWhite_c5872_589, TraesCS6A01G383800 had significantly higher TKW than the accessions carying T allele. Interestingly, these genes were highly expressed in the grain-tissues, demonstrating their pivotal role in controlling the grain architecture. Conclusions: These results are valuable for identifying regions associated with kernel weight and dimensions and potentially help breeders in improving kernel weight and architecture-related traits in order to increase wheat yield potential and end-use quality.Fil: Schierenbeck, Matías. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales. Cátedra de Cerealicultura; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Leibniz Institute of Plant Genetics and Crop Plant Research; AlemaniaFil: Alqudah, Ahmad M.. University Aarhus; DinamarcaFil: Lohwasser, Ulrike. Leibniz Institute of Plant Genetics and Crop Plant Research; AlemaniaFil: Tarawneh, Rasha A.. Leibniz Institute of Plant Genetics and Crop Plant Research; AlemaniaFil: Simon, Maria Rosa. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales. Cátedra de Cerealicultura; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Börner, Andreas. Leibniz Institute of Plant Genetics and Crop Plant Research; Alemani

Association mapping unravels the genetics controlling seedling drought stress tolerance in winter wheat

Drought is a major constraint in wheat (Triticum aestivum L.) grain yield. The present work aimed to identify quantitative trait nucleotides (QTNs)/ candidate genes influencing drought tolerance-related traits at the seedling stage in 261 accessions of a diverse winter wheat panel. Seeds from three consecutive years were exposed to polyethylene glycol 12% (PEG-6000) and a control treatment (distilled water). The Farm-CPU method was used for the association analysis with 17,093 polymorphic SNPs. PEG treatment reduced shoot length (SL) (-36.3%) and root length (RL) (-11.3%) compared with control treatments, while the coleoptile length (CL) was increased by 11% under drought conditions, suggesting that it might be considered as an indicator of stress-tolerance. Interestingly, we revealed 70 stable QTN across 17 chromosomes. Eight QTNs related to more than one trait were detected on chromosomes 1B, 2A (2), 2B, 2D, 4B, 7A, and 7B and located nearby or inside candidate genes within the linkage disequilibrium (LD) interval. For instance, the QTN on chromosome 2D is located inside the gene TraesCS2D02G133900 that controls the variation of CL_S and SL_C. The allelic variation at the candidate genes showed significant influence on the associated traits, demonstrating their role in controlling the natural variation of multi-traits of drought stress tolerance. The gene expression of these candidate genes under different stress conditions validates their biological role in stress tolerance. Our findings offer insight into understanding the genetic factors and diverse mechanisms in response to water shortage conditions that are important for wheat improvement and adaptation at early developmental stages.Fil: Schierenbeck, Matías. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Leibniz Institute of Plant Genetics and Crop Plant Research; Alemania. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales. Cátedra de Cerealicultura; ArgentinaFil: Alqudah, Ahmad M.. Qatar University; QatarFil: Thabet, Samar G.. Fayoum University; EgiptoFil: Lohwasser, Ulrike. Leibniz Institute of Plant Genetics and Crop Plant Research; AlemaniaFil: Simón, María Rosa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales. Cátedra de Cerealicultura; ArgentinaFil: Börner, Andreas. Leibniz Institute of Plant Genetics and Crop Plant Research; Alemani

GWAS revealed effect of genotype × environment interactions for grain yield of Nebraska winter wheat

Background: Improving grain yield in cereals especially in wheat is a main objective for plant breeders. One of the main constrains for improving this trait is the G × E interaction (GEI) which affects the performance of wheat genotypes in different environments. Selecting high yielding genotypes that can be used for a target set of environments is needed. Phenotypic selection can be misleading due to the environmental conditions. Incorporating information from phenotypic and genomic analyses can be useful in selecting the higher yielding genotypes for a group of environments. Results: A set of 270 F3:6 wheat genotypes in the Nebraska winter wheat breeding program was tested for grain yield in nine environments. High genetic variation for grain yield was found among the genotypes. G × E interaction was also highly significant. The highest yielding genotype differed in each environment. The correlation for grain yield among the nine environments was low (0 to 0.43). Genome-wide association study revealed 70 marker traits association (MTAs) associated with increased grain yield. The analysis of linkage disequilibrium revealed 16 genomic regions with a highly significant linkage disequilibrium (LD). The candidate parents’ genotypes for improving grain yield in a group of environments were selected based on three criteria; number of alleles associated with increased grain yield in each selected genotype, genetic distance among the selected genotypes, and number of different alleles between each two selected parents. Conclusion: Although G × E interaction was present, the advances in DNA technology provided very useful tools and analyzes. Such features helped to genetically select the highest yielding genotypes that can be used to cross grain production in a group of environments

Genetic dissection of grain architecture-related traits in a winter wheat population

Background: The future productivity of wheat (T. aestivum L.) as the most grown crop worldwide is of utmost importance for global food security. Thousand kernel weight (TKW) in wheat is closely associated with grain architecture-related traits, e.g. kernel length (KL), kernel width (KW), kernel area (KA), kernel diameter ratio (KDR), and factor form density (FFD). Discovering the genetic architecture of natural variation in these traits, identifying QTL and candidate genes are the main aims of this study. Therefore, grain architecture-related traits in 261 worldwide winter accessions over three field-year experiments were evaluated. Results: Genome-wide association analysis using 90K SNP array in FarmCPU model revealed several interesting genomic regions including 17 significant SNPs passing false discovery rate threshold and strongly associated with the studied traits. Four of associated SNPs were physically located inside candidate genes within LD interval e.g. BobWhite_c5872_589 (602,710,399 bp) found to be inside TraesCS6A01G383800 (602,699,767-602,711,726 bp). Further analysis reveals the four novel candidate genes potentially involved in more than one grain architecture-related traits with a pleiotropic effects e.g. TraesCS6A01G383800 gene on 6A encoding oxidoreductase activity was associated with TKW and KA. The allelic variation at the associated SNPs showed significant differences betweeen the accessions carying the wild and mutated alleles e.g. accessions carying C allele of BobWhite_c5872_589, TraesCS6A01G383800 had significantly higher TKW than the accessions carying T allele. Interestingly, these genes were highly expressed in the grain-tissues, demonstrating their pivotal role in controlling the grain architecture. Conclusions: These results are valuable for identifying regions associated with kernel weight and dimensions and potentially help breeders in improving kernel weight and architecture-related traits in order to increase wheat yield potential and end-use quality.Este artículo tiene una corrección que puede verse haciendo clic en "Documentos relacionados".Facultad de Ciencias Agrarias y Forestale

Genetic dissection of photoperiod response based on GWAS of pre-anthesis phase duration in spring barley

Heading time is a complex trait, and natural variation in photoperiod responses is a major factor controlling time to heading, adaptation and grain yield. In barley, previous heading time studies have been mainly conducted under field conditions to measure total days to heading. We followed a novel approach and studied the natural variation of time to heading in a world-wide spring barley collection (218 accessions), comprising of 95 photoperiod-sensitive (Ppd-H1) and 123 accessions with reduced photoperiod sensitivity (ppd-H1) to long-day (LD) through dissecting pre-anthesis development into four major stages and sub-phases. The study was conducted under greenhouse (GH) conditions (LD; 16/8 h; ∼20/∼16°C day/night). Genotyping was performed using a genome-wide high density 9K single nucleotide polymorphisms (SNPs) chip which assayed 7842 SNPs. We used the barley physical map to identify candidate genes underlying genome-wide association scans (GWAS). GWAS for pre-anthesis stages/sub-phases in each photoperiod group provided great power for partitioning genetic effects on floral initiation and heading time. In addition to major genes known to regulate heading time under field conditions, several novel QTL with medium to high effects, including new QTL having major effects on developmental stages/sub-phases were found to be associated in this study. For example, highly associated SNPs tagged the physical regions around HvCO1 (barley CONSTANS1) and BFL (BARLEY FLORICAULA/LEAFY) genes. Based upon our GWAS analysis, we propose a new genetic network model for each photoperiod group, which includes several newly identified genes, such as several HvCO-like genes, belonging to different heading time pathways in barley

Gasless Trans-Umbilical Laparoscopically-Assisted Appendectomy in the Pediatric Population: An Early Experience

Background: The aim of this study is to determine the feasibility and safety of the single-port gasless trans-umbilical laparoscopically-assisted appendectomy in the pediatric age group at a single center in a tertiary university hospital in Jordan. Methods: Between April 2018 and July 2019, the surgical records of all patients aged between 0 and 13 years treated with trans-umbilical laparoscopic-assisted appendectomy TULAA for a suspected appendicitis following a clinical, laboratory and ultrasound findings were reviewed retrospectively. Baseline characteristics, white blood cell count, operative time, intraoperative findings, need for additional trocars or for conversion, length of hospital stay and surgical complications were reported.Results: 36 cases were included in the study, 23 (64%) were completed successfully using the gasless TULAA technique. Gas insufflation was needed in 10 (28%) cases and only 3 (8%) had to be converted to the three-port laparoscopic appendectomy technique. There was no significant difference between the gaseous and gasless groups in terms of baseline characteristics, BMI, surgery duration, postoperative recovery period or length of stay. However, the group of patients who needed gas insufflation to complete the procedure had a higher white blood cell count compared to the gasless group. The surgery was completed successfully by senior general surgery residents in 27 (75%) cases while the consultant’s intervention was needed in the remaining cases. The gasless TULAA group were less likely to require complex analgesia (i.e., IV analgesia) compared to the gasless group (OR=0.683).Conclusions: Gasless TULAA is a feasible procedure that can be performed safely by surgical residents as an initial approach for all grades of acute appendicitis in the pediatric age group