Screening Of Ac/Ds Mutants For Plant Architecture And Analysis Of Ds Insertion Sites In Maize

Maize is one of the most important food crops in China,which plays a very important role in ensuring China's food security.Maize plant architecture is the key factor determining density corn planting density.The inbred lines with excellent plant architecture were selected and the key loci and genes controlling maize plant architecture traits were searched and utilized,which laid a foundation for breeding and popularizing high-yield maize hybrids resistant to high-density adversity.The construction of mutant pool is an important method to solve germplasm resource innovation and functional genome research.Maize mutagenesis pool can be used to screen out plant-architecture related mutants and further study the key genes controlling related traits and their functions.In this experiment,on the basis of more than 5000 mutation lines of corn Ac/Ds mutant pool constructed in the early stage,400 families were taken out from the mutant pool for screening and identification of plant-related mutants.Meanwhile,the sequence of Ds flanks was massively amplified by adapter-RCR to determine the insertion position of Ds in corn genome.The main results are as follows:1.In this study,phenotypic identification was performed on 400 mutant families from 5,000 stable genetic mutant pools.In addition,198 mutant families related to plant architecture were identified from these 400 families,and a total of 237 individual strains were mutated in these 198 mutant families.The main traits of these mutant plants were dwarfing mutation,leaf Angle mutation,spike position mutation,tassel branch Angle and tassel branch number mutation.At the same time,the panicle traits of 1965 ears were investigated and identified,and the results showed that 844 ears showed variations,including bald tip,grain development defect,cob color change,ear bending,ear rot resistance and grain type.2.In this experiment,20 families were randomly selected from 400 field identification families to analyze the Ds insertion genome locus.After PCR amplification detection,6 families with positive Ac factor were excluded,and genomic DNA was extracted from the remaining 14 families.The flanking sequence was identified and sequenced using adapter-PCR.The results showed that a total of 990 flanking sequences containing insertion Ds sites were obtained in 14 families.There were differences in the number of flanking sequences of Ds insertion sites between different families.After BLAST alignment of B73 V3 version reference genome,174 genes that might be related to Ds insertion were found,which laid a good foundation for the authenticity verification of subsequent Ds insertion sites.3.The statistical analysis of the chromosome locations of 174 Ds factors inserted into the genome of maize showed that the Ds factors inserted into the chromosome 10 of maize had 52 sites,which was significantly higher than other chromosomes,while the distribution of Ds factors on chromosome 1 to 9 was uneven,and the number of sites on chromosome 9 was the least.This may be due to the fact that the Ds donor of the inbred line W22 is located on chromosome 10,leading to the main occurrence of Ds factor transposings in adjacent locations.However,the Ds mutant library covering the whole genome of corn can also be constructed by using the Ac/Ds system of corn.4.33 genes related to cell division,hormone synthesis and hormone response were identified from 174 genes,which can be distributed in 10 families.At the same time,the comparison and analysis between these 10 families and the phenotypic results revealed that 5 families showed trait variation,One dwarf plant appeared in family 34 and family 425 respectively.Two dwarf plants appeared in family 426.The variation of plant height and panicle height was found in family 428.Variation in spike position was also observed in family 460.Therefore,the screening and identification of these families laid a foundation for the subsequent verification of Ds insertion authenticity.5.One family(34)was selected from 10 families that may be related to strain type to verify the authenticity of the insertion site.Primer5.0 was used to design two pairs of primers for each of the two candidate genes in family 34 for PCR amplification.The amplification results showed that two target bands were expanded in the gene GRMZM5G822829,indicating that the mutant single plant in the family was a hybrid insertion mutation,so the dwarf single plant in family 34 may be caused by the insertion of Ds factor.