Diversity Of Wild Barley In Agronomic Traits And Its Genetic Basis

Barley(Hordeum vulgare L.)is one of the oldest cultivated cereal crop and the fourth largest cereal crop produced worldwide in quantity,and it is utilized in the food,feed,malt and brewing industries.Barley is possibly the most widely adapted cereal crop with high yield in higher latitudes and farther into deserts than any other cereal crop.Wild barley(Hordeum spontaneum)is the progenitor of cultivated barley,which offers considerable potential as a genetic resource for barley improvement.Naturally occurring wild barley populations are distributed primarily across the Fertile Crescent,Central Asia and Tibet.The study of the origin,genetic variation and evolutionary relationships in barley is important in the development,conservation and restoration of biodiversity of wild germplasm.Primarily,response to physical characteristics of the environment can be reflected as plant stress.The environmental effect could only be measured in connection to the organism which is going through stress.Adaptation in basic terms can be stated as the process of change in an organism to conform successfully with new environmental conditions,whereby the organism or group of organisms acquire characteristics,involving changes in morphology,physiology or behavior that tend to develop their survival and reproductive success in the particular environment.This mechanism is known as evolutionary adaptation or genotypic adaptation and it leads to evolution.The basis of environmental adaptation is the genomic divergence.Genomic divergence is the variation between the genomes of individuals or populations within the same species,is ranging from small-scale nucleotide variations to large-scale structural variations at gene and chromosomal levels.Genomic divergence is the main factor responsible for differential adaptation of individuals or populations to heterogeneous or contrasting environments with different biotic and abiotic stress pressures.This study provides the fundamental aspects of genomic divergence and microenvironmental adaptation.Genetic or DNA based marker techniques are used in evolutionary ecology and genetic studies of plant sciences.The technical developments and genome based findings have led to the improvement of molecular marker techniques.The presence of different molecular markers and characteristically different principles,methodologies and functions require cautious attention in selecting one or more of such techniques.No molecular markers are to be had yet to fulfill all the requirements needed by researchers.This study gives comprehensive knowledge about the most widely used molecular marker techniques used in plant genomics.A major part of the daily caloric intake of human societies around the world is derived from a diverse range of foods prepared from cereals,including barley.The cereals are noteworthy for the unusual composition of their cell walls than other higher plants.Most significantly,walls of cereals comprise of major constituents,the(1,3;1,4)-β-D-glucans,which are not widely distributed outside the grass family.1.Direct Comparison of β-Glucan Content in Wild and Cultivated BarleyThe(1,3;1,4)-β-D-glucan is a soluble fiber,which is available in oat and barley,that have been gaining interest due to its multiple bioactive and functional properties.In vitro as well as in vivo studies in animals and humans have proven and documented its beneficial role in reducing the risks of coronary heart disease,insulin resistance,dyslipidemia,hypertension,obesity and immune modulating.The fermentability of(1,3;1,4)-β-D-glucans and its ability to create viscous solutions in the human gut brings these great health benefits.The viscosity of(1,3;1,4)-β-D-glucan glucan depends on the physicochemical properties such as molecular weight,solubility,and concentration.The extraction conditions influence the rheology,viscosity,and molecular weight of(1,3;1,4)-β-D-glucan.Physicochemical properties of(1,3;1,4)-β-D-glucan are strongly affected by the genetic attributes and environmental condition.The wide range of effectiveness reported are explained by the properties of the(1,3;1,4)-β-D-glucan in the diets used,as well as the dose.Conversely,(1,3;1,4)-β-Dglucan have anti-nutritive effects in monogastric animals such as pigs and poultry and are often considered to be undesirable components of raw materials in the malting and brewing industries.This study provides fundamentals,applications,benefits and recent advances of(1,3;1,4)-β-D-glucan research in several aspects.Also,in this study,(1,3;1,4)-β-D-glucan content in wild barley from Fertile Crescent,Central Asia,Tibet,and cultivated varieties from the representative regions worldwide were systematically investigated using the mixed-linkage β-glucan assay.Results showed that the mean(1,3;1,4)-β-D-glucan content of wild accessions and cultivated varieties were 5.17 % and 3.81 %,and the coefficient of variation(CV %)is 24.18 % and 18.11 %,respectively.(1,3;1,4)-β-D-glucan content was significantly different(p ≤ 0.001)between wild and cultivated barely samples and,wild barley showed higher(1,3;1,4)-β-D-glucan content and higher variation.This study depicts a clear idea about the(1,3;1,4)-β-D-glucan content in wild and cultivated barley,their locations and elite germplasm for barley(1,3;1,4)-β-Dglucan genetic improvement programs,and also shed light to trace barley domestication in relation to grain metabolite view.2.Genomic,Morphological,Chemical Divergence and Microenvironmental Adaptation in Wild BarleyMicroenvironmental adaptation plays a major role in the evolution.Genetic diversity is one of the most important indicator for molecular evaluation studies.In this study,molecular markers together with morphological and biochemical traits were used to investigate the diversity and divergence of wild barley populations,obtained from different microenvironments in Mt Gilboa,Israel.High level of polymorphism was observed with molecular markers and the significant differences were found in morphological and biochemical traits analysis.The genetic variation(50.5 % polymorphism)was recognized between the populations.Cluster analysis grouped genotypes into two clear groups suggesting that they have adapted to two different microenvironments.Some morphological traits such as plant height,number of tillers,days to flowering,flag leaf length and number of seeds per spike exhibited significant difference(p ≤ 0.05),and several chemical compounds such as fiber and crude protein content also exhibited significant difference(p ≤ 0.05)between microenvironments.Hence,our results demonstrated the genomic divergence and adaptation of wild barley to different microenvironments,under common main environment.Furthermore,the results demonstrated the effectiveness of molecular markers,morphological and biochemical traits in detecting variations exerted by adaptation to microenvironments.3.Genome‐Wide Identification and Analysis of CslF Gene Family in BarleyMembers of the cellulose synthases/cellulose synthase-like(CesA/Csl)genes superfamily responsible for the(1,3;1,4)-β-D-glucan synthesis.Under that superfamily,Cellulose synthase-like(Csl)F family has been proven to be one of the most crucial genes regulating(1,3;1,4)-β-D-glucan synthesis,which is one of the important component of cereal cell walls,advantageous for human nutrition,but disadvantageous in animal nutrition,malting and brewing industries.Although it has been widely studied,it is not well understood at present in barley,in particular its structural compositions and organizations at whole genome scale.Given the importance of the(1,3;1,4)-β-D-glucans and the newly completed barley genome,we identified barley CslF gene family through a genome-wide search method.A total of 18 CslF genes were identified in the barley genome.Then,phylogenetic analyses classified them into 3 groups,and these CslFs shared more similar conserved motif compositions.A new motif,D,D,WQxxD was also identified,which was responsible for the cellulose synthase.Furthermore,the expression profiles of these HvCslFs,were systematically investigated in different tissues using RNA-seq data,and then the tissuespecific candidates were found.Finally,correlation network analysis identified 11 CslF genes involved in the correlation pathway.Overall,this study provided useful information about the genomic organization and dynamics of CslF gene family in barley,which will facilitate the functional surveys of CslF genes in barley and beyond.