Development and identification of two novel wheat-rye 6R derivative lines with adult-plant resistance to powdery mildew and high-yielding potential

Powdery mildew,caused by Blumeria graminis f.sp.tritici(Bgt),is a devastating disease that seriously threatens wheat yield and quality.To control this disease,host resistance is the most effective measure.Compared with the resistance genes from common wheat,alien resistance genes can better withstand infection of this highly variable pathogen.Development of elite alien germplasm resources with powdery mildew resistance and other key breeding traits is an attractive strategy in wheat breeding.In this study,three wheat-rye germplasm lines YT4-1,YT4-2,and YT4-3 were developed through hybridization between octoploid triticale and common wheat,out of which the lines YT4-1 and YT4-2 conferred adult-plant resistance(APR)to powdery mildew while the line YT4-3 was susceptible to powdery mildew during all of its growth stages.Using genomic in situ hybridization,multi-color fluorescence in situ hybridization,multi-color GISH,and molecular marker analysis,YT4-1,YT4-2,and YT4-3 were shown to be cytogenetically stable wheat-rye 6R addition and T1RS.1BL translocation line,6RL ditelosomic addition and T1RS.1BL translocation line,and T1RS.1BL translocation line,respectively.Compared with previously reported wheat-rye derivative lines carrying chromosome 6R,YT4-1 and YT4-2 showed stable APR without undesirable pleiotropic effects on agronomic traits.Therefore,these novel wheat-rye 6R derivative lines are expected to be promising bridge resources in wheat disease breeding.

Cytological and genetic analyses of a wheat-rye 2RL ditelosomic addition line with adult plant resistance to powdery mildew

Rye(Secale cereale genome RR),a close relative of common wheat,possesses valuable resistance genes for wheat improvement.Due to the co-evolution of pathogen virulence and host resistance,some resistance genes derived from rye have lost effectiveness.Development and identification of new,effective resistance genes from rye is thus required.In the current study,wheat-rye line WR56 was produced through distant hybridization,embryo rescue culture,chromosome doubling and backcrossing.WR56 was then proved to be a wheat-rye 2 RL ditelosomic addition line using GISH(genomic in situ hybridization),mc-FISH(multicolor fluorescence in situ hybridization),ND-FISH(non-denaturing FISH),mc-GISH(multicolor GISH)and rye chromosome arm-specific marker analysis.WR56 exhibited a high level of adult plant resistance to powdery mildew caused by Blumeria graminis f.sp.tritici(Bgt).This resistance was carried by the added 2 RL telosomes and presumed to be different from Pm7 which is also located on chromosome arm 2 RL but confers resistance at the seedling and adult stages.WR56 will be a promising bridging parent for transfer of the resistance to a more stable wheat breeding line.A newly developed2 RL-specific KASP(kompetitive allele specific PCR)marker should expedite that work.

Countermeasures to Achieve High-quality Development of Dairy Industry in Xinjiang:A Case Study of Tianrun Dairy Industry

As a high-quality milk source base in China,Xinjiang has an innate foundation for the development of modern high-quality milk industry.In this paper,it was pointed out that the uneven distribution of interests between the upstream and downstream of the industry was the influencing factor restricting the development of modern dairy industry in Xinjiang.At the same time,the related information of Tianrun Group,which was the leading enterprise in Xinjiang,was analyzed.According to analysis,it was found that through the construction and development of large-scale,standardized and modern milk source base,balance of the upstream and downstream interests,improvement of the combination system of planting and breeding,the added value of products was enhanced and the anti risk ability of enterprises was increased.In addition,it was also pointed out that under the leadership of leading enterprises,Xinjiang would embark on the development road of modern high-quality milk industry with circular economy,resource-saving,environment-friendly,quality and efficiency,operation-saving,independent innovation and industrial integration in the future.

Genome-wide developed microsatellite markers for the melon thrips Thrips palmi Karny(Thysanoptera:Thripidae)

The melon thrips, Thrips palmi Karny, is an economically important pest on many vegetables from Solanaceae and Cucurbitaceae. In this study, we developed novel microsatellite markers for Thrips palmi. First, we obtained randomly sequenced regions from the genome using next-generation sequencing and assembled 356 Mb genomic sequences. In total, 155,789 microsatellites were identified from the genomic sequences, of which, 64.02% were loci of dinucleotide repeat. Sixty primer pairs were initially validated in seven individuals. Thirty-five polymorphic markers were retained according to the amplification efficiency and polymorphism.These 35 microsatellite loci were then assessed in 96 individuals in four geographical populations collected from China. The allele numbers ranged from 2 to 19 with an average value of 6.9 per locus, while the polymorphism information content ranged from 0.2219 to 0.8490.The observed and expected heterozygosity varied from 0.5252 to 0.5367 and 0.5934 to 0.6148,respectively. Genetic structure was found between populations from southern and northern China. These novel microsatellite markers developed in our study provide abundant molecular markers for the genetic study of T. palmi.

Genome-wide characterization of microsatellites and development of polymorphic markers shared between two weevils of Eucryptorrhynchus(Coleoptera:Curculionidae)

The weevils Eucryptorrhynchus brandti(Harold)and E.scrobiculatus(Motschulsky)are two pests of the tree of heaven,Ailanthus altissima.They usually co-occur on their host tree.However,these two species have a niche separation with different eggs-laying locations and larvae-feeding parts on the tree.Here,we characterized the distribution of microsatellites in the genome and developed genome-wide microsatellite markers shared between these two weevils.A total of 12,524 and 11,030 potential microsatellites were identified for E.brandti and E.scrobiculatus,respectively.Microsatellites with AT,TA,AC,TG,CA repeat motifs were most common for both species.We designed primers universal for two weevils and developed 14 loci with high amplification efficacy and polymorphism.We validated these microsatellite markers in three populations of each species.In E.brandti,the observed and expected heterozygosity for the genotyped loci ranged from 0.17-0.24 and 0.44-0.54;in E.scrobiculatus,the above values ranged from 0.06-0.18 and 0.18-0.27.Based on the developed microsatellite markers,we found that populations of both weevils have a clear pattern of genetic differentiation.Our study provides valuable genetic markers for ecological,genetic,and evolutionary study of these two weevils.

Mitochondrial gene rearrangement within genus Gasteruption(Hymenoptera: Evanioidea: Gasteruptiidae)

The complete mitochondrial genome of the Gasteruption parvicollarium Enderlein （GenBank accession number： KR270643） was sequenced in the study. Totally 17 009 bp sequence was determined with an A＋T content of 83.81%, including full set of typical animal mitochondrial genes. Two protein-coding and 10 tRNA genes as well as the A＋T-rich region were rearranged compared with the putative ancestral arrangement of insects. Most of the rearranged genes were located in the ancestral region of trnl-trnQ-trnM-nad2-trn W-trnC-trn Y- coxl-trnL2. The other rearranged genes are trnN and trnS1 located in the tRNA cluster trnA- trnR-trnN-trnSl-trnE-trnF and trnS2 located between cob and nadl. Remote inversion is dominant rearrangement event in G. parvicollarium mitochondrial genome, involving two protein-coding and 8 tRNA genes. Compared with the other mitochondrial genome reported in the same genus of Gasteruption, the inverted trnN was translocated to the tRNA cluster between cox1 and nad2 in G. parvicollarium. This is the first report of mitochondrial gene rearrangement occurred within genus of Hymenoptera. Our study points to a recently occurred gene rearrangement event in the Gasteruption species.

Conserved profiles of digestion by double restriction endonucleases in insect genomes facilitate the design of dd RAD

Double-digested Restriction Site Associated DNA Sequencing（ddRAD） through next-generation sequencing（NGS） generates large numbers of loci for characterizing genomewide variation among multiple samples using next-generation sequencing. Different combinations of restriction endonucleases（REs） may produce varying size distributions of digested fragments, which affect the number of genotyped loci. Understanding digestion profiles across different species will help in selecting REs for digestion in a particular organism. In this study, we use of genome sequences to compare the in silico digestion profile of 26 combinations of REs in 131 insect species with two simulation programs. The number of digested fragments in the 300-450 bp range increases linearly with the size of the genome. Different species and insect orders showed similar profiles when digested by different combinations of REs in silico, indicating the conservation of digestion by double enzymes in insect genomes. Combinations with Nla III or TaqαI usually produced higher number of fragments in the range 300-450 bp, while combinations with EcoRI or MluCI produced fewer fragments. The proportion of fragments with the same overhangs at the two ends of digested DNA was higher than those with different overhangs. The two four-base enzyme pairs produced more fragments in the 300-450 bp range than pairs of four-base ＋ six-base enzymes. Experimental digestion of three species from Hymenoptera, Lepidoptera and Thysanoptera showed profiles congruent with in silico expectations. Our results shed light on understanding the digestion profiles of insect genomes and provide guidance on selecting REs for ddRAD projects.