Genetic Analysis And Main Gene Separation Of Blue Grain In Hulless Barley

Hordeum vulgare Linn.var.Nudum Hook.F.belong to Hordeum Linn of Gramineae.Some hulless barley in Tibetan Plateau carried the blue grain traits.Blue grain trait can provide more anthocyanin as nutrient for human.It's also a good genetic marker for genetic analysis.The genetic mechanism behind blue grain trait is not yet clear.In this study,the recombinant inbred lines of blue grain cultivar Dulihuang and white grain cultivar Kunlun14 were used to identify the genetic loci controlling the blue grain traits.Through high-throughput transcriptome sequence and bioinformatics analysis,the genes related to anthocyanin biosynthesis was compared in their expression level and the structural differences of genes in the aleurone of blue and white grain cultivar.The candidate genes controlling blue grain trait were also isolated.This research should provide a good theoretical basis for the analysis of the molecular genetic mechanism of blue aleurone traits and breeding new blue grain cultivars in barley.The main results are as follows:1?In the 195 recombinant inbred lines,46 lines carried blue grains and 149 lines were white grain.The separation ratio of blue grain and white grain traits was approximately 1:3 in the recombinant inbred lines.It could be inferred that blue grain trait was a recessive trait,which was controlled by a recessive gene.2?Compared with white aleurone,13,778 genes expressed differentially,including 5726 up-regulated genes and 8052 down-regulated genes in blue aleurone through the RNA-seq analysis.The maximum changes pathways were flavonoid biosynthesis anthocyanin biosynthesis.Further analysis revealed that the structural gene of anthocyanin biosynthesis had a higher expression level in the blue-grained barley,which indicated that the anthocyanin biosynthesis is more active in blue aleurone.The transcription factor HvMYC gene and HvMYB gene,regulating anthocyanin biosynthesis,expressed higher also in blue aleurone.The maximum log2 Fold value of HvMYC and HvMYB were 9.47 and 4.10,respectively.The structure genes of anthocyanin biosynthesis were regulated by HvMYC gene and HvMYB gene.Therefore,the high expression of HvMYC and HvMYB genes is probably the key gene of high anthocyanin accumulation in blue grains barley.3?Based on the transcriptome information,the HvMYB and HvMYC genes expressed in blue aleurone was isolated.The coding sequence of HvMYB was 732 bps,belonging to the SANT supergene family.The maximum hydrophobicity of HvMYB was 1.55,the minimum value is-2.53 and the average hydrophobic value is-0.49.This indicates that the HvMYB protein has a certain degree of hydrophilicity.The transmembrane region analysis that the secondary structure of HvMYB protein contained ?-helix(45.5%)and the irregular coil(35.8%),extended chains(12.8%),?-turns(5.84)%).The coding sequence of HvMYC was 1669 bps,belonging to the bHLH supergene family.The maximum hydrophobicity of HvMYC protein was 2.3,the minimum value was-3.2 and the average hydrophobic value is-0.45,which indicates that HvMYC protein has a certain degree of hydrophilicity.The secondary structure of HvMYC gene is composed of ?-helices(44.3%),irregularly coiled(32.6%),extended chains(10.5%),?-turns(4.57%).The molecular phylogenetic analysis showed that the isolated HvMYB and HvMYC genes were closely related to the gene regulating anthocyanin biosynthesis in the species such as Triticum,Aegilops tataschii,Brachypodium distachyon.