Molecular Mechanisms Of Specific Characters Of Triticum Aestivum And Akebia Trifoliate Based On Multi-Omics Data

Triticum aestivum and Akebia trifoliate are important plant resources in the world.They not only have high economic value,but also are important to food and oil security in China.Biological yield of crops mainly comes from photosynthesis of leaves,and photosynthetic efficiency directly affects the yield.Albino mutant of wheat leaves is an important material for researching the mechanism of photosynthesis,chlorophyll synthesis and chloroplast development in higher plants.Mapping and functional analysis of genes related to albino traits not only can enrich the theoretical content of photosynthesis,but also lay a foundation for high photosynthetic efficiency molecular breeding in wheat.Akebia trifoliate is a kind of edible medicinal and oil homologous plant.It has the characteristics of strong adaptability,low planting technology requirements,high added value of products and broad market prospects.However,the genetic analysis of quality traits and its genomic information has been unclear even basically blank.The weak fundamental research has greatly limited the development speed of Akebia trifoliate industrialization.This study will explore the molecular mechanism of wheat albino mutants and important traits such as food,medicine and oil of Akebia trifoliate by genomics,transcriptome,metabolome and reduced-representation genomics,aiming to systematically reveal the molecular mechanism laying a foundation for directional design breeding.The main results in this study are as follows:1.The traits of wheat albino mutant M6 were identified belong to a low temperature-sensitive green-return albino mutant.A genetic isolation population was constructed by crossing wheat albino mutant M6 with wild type CN19.Genetic analysis showed that albino phenotype was controlled by a pair of recessive nuclear genes.The mutant gene was mapped on the 6.5Mb sequence segment of chromosome2 A from 718819312 to 725306514 loci by bulked segregation analysis combined with reduced-representation sequencing.Fourteen candidate genes were screened in the localization interval.2.The content of intermediate products and the activity of key enzymes in chlorophyll synthesis pathway of albino mutants were determined.The results showed that porphyrinogen III and products in subsequent steps decreased significantly.Sequence polymorphisms of Urod gene between mutants and wild-type materials were cloned and analyzed.RNA-Seq of materials at different temperatures were also analyzed.The results showed that the mutant gene led to more conversion of porphyrinogen III into heme,thus inhibiting chlorophyll synthesis.The expression of genes related to chlorophyll synthesis was verified by real-time fluorescence quantitative technology.3.The next-generation sequencing technology was used to investigate the whole genome of Akebia trifoliate.58.59 Gb high-quality sequencing data was obtained.K-mer analysis showed that the genome size of Akebia trifoliate was about 618.52 Mb,the repeat sequence content was about 43.07%,and the heterozygosity rate was about1.01%.56.6 Gb and 40.34 Gb data Akebia trifoliate genome were obtained by third-generation sequencing technology Pac Bio and Hi-C technology,respectively.Finally,Akebia trifoliate genome was assembled to a chromosome level genome with scaffold length 652.8 Mb,contig N50 = 1.57 Mb and scaffold N50 = 35.8Mb values.Karyotype analysis showed that chromosome ploidy and number of Akebia trifoliata were 2n=2x=32 by FISH technology.23938 predictive genes were annotated.Evolution analysis of gene families showed that 163 families contracted and 157 families expanded,and species phylogenetic tree was constructed.4.LC-ESI-MS/MS and Illumina Hi Seq TM2500 were used to determine the metabolome and transcriptome data of four developmental stages and three tissues of Akebia trefolia fruit.Further analysis showed that the metabolic pathway of aromatic amino acids synthesizing flavonoids may play an important role in the nutritional and medicinal characters of Akebia trifoliate.The expression of trp A,PAL and Tyr1 genes is the key factor of this metabolic regulation.