Creation,Identification And Genetic Analysis Of Alien Chromosome Lines Between Cultivatied Peanut And Diploid Wild Species Arachis Duranensis

Peanut?Arachis hypogaea L.,2n=4x=40,AABB?is an important oil and economic crop in the world.With the technique improving of agricultural production and market changing in the human consumption,it is essential to improve agronomic,resistance and quality traits of peanuts.Due to the narrow genetic basis of peanut cultivars,the available genetic resources are limited.However,during the natural selection in the long histry,the wild peanut species developed a higher level of disease resistance and insect resistance and contained rich variations in seeds quality,which provided potential utilization in the breeding of superior peanut cultivars.Therefore,distant hybridization can transfer beneficial resistance genes from wild species to cultivated peanut and create germplasm resources,which is conducive to broadening the genetic basis of peanuts and facilitate variety improvement.A.duranensis is one of the two ancestor wild species of cultivated peanuts,and has harboured many stress resistance traits.Silihong is a landrace with early maturity,poor stress resistance and bears multiple seeds in each pod.In the previous study,Slh were crossed with A.duranensis to obtain interspecies hybrid F₁,and then seedlings were treated with colchicine to produce seeds which were named as Am1210.For the present study,the reference genome sequences of cultivar Tifrunner and wild species A.duranensis were first analyzed by MISA,and 135529 and 512900 SSR sites were identified from the genomes of A.duranensis and Tifrunner,respectively.The results show that SSR motifs are unevenly distributed in the genome,and there were differences in parameters such as SSR type,number of repetitions,and SSR length.Using the identified SSR flanking sequences,37027 pairs of A.duranensis SSR primers were designed,accounting for 28.41%of the total SSR sites.Through electronic PCR analysis of the amplification of SSR primers on the entire genome sequence of Tifrunner and A.duranensis,primer pairs that can generate specific amplification sites on the genome of A.duranensis were obtained.30 SSR markers were selected from A01 to A10 chromosomes,a total of 300 SSR markers were identified by amplification and electrophoresis on the genomic DNA of Tifrunner and A.duranensis.In the end,61 A.duranensis-specific SSR markers were obtained,accounting for 20.3%.In addition,screening 997 peanut SSR molecular markers preserved in the laboratory,25A.duranensis-specific molecular markers were also obtained.These markers are finally used to identify the chromosomes of the progenies of Slh and A.duranensis,and to track the alien chromosome variation lines.BC₂F₁was obtained by successive backcrossing of Slh with Am1210 and,which was analysised using metaphase mitochondrial chromosome observation.As a result,17 chromosomal variant lines were obtained with the number of chromosomes between39 and 45.BC₂F₁was selfed to obtain BC₂F₂,and then the A.duranensis specific SSR markers were used to screen the BC₂F₂ population,and it was found that 152 variant lines containing alien chromosomes which was selfed to obtained BC₂F₃ and BC₂F₄generations.Repetitive oligonucleotide probe,A.duranensis and A.ipa?nsis genomic DNA probe and chromosome-specific single copy probe library were used for sequential FISH and GISH identification of BC₂F₃ and BC₂F₄.A total of one disomic addition line,five chromosome addition lines and 12 potential translocation lines or introgression lines with changed traits were obtained.It not only lays a material foundation for future breeding work,but also facilitates the study of the role of A.duranensis gene.In addition,the field inoculation of web blotch diseaseis also conducted on Slh,interspecific hybrid F₁ and hexaploid Am1210,and it was found that hybrid F₁ and hexaploid Am1210 showed high resistance to web blotch.The resistance is significantly higher than that of the Slh.This study shows that the hexaploid Am1210is a potential resistance material to web blotch disease.In summary,this study developed and screened a series of molecular markers that can be effectively used to track and identify the alien chromosomes in the offspring of the hybrid of A.duranensis.We also obtained some chromosome addition lines,translocation lines and introgression lines containing A.duranensis chromosome.The A.duranensis genome introgression line was found to be highly resistant to web blotch disease,which laid the foundation for the study of A.duranensis chromosome effects and the use of its beneficial genes.