Gene Mapping Of Chlorophyll Fluorescence Parameters And Candidate Genes Discovering In Maize

Maize (Zea mays L.) is an important crop which serves as food and forage. Increasing maize production by increasing the planting density is a important achievement in modern maize breeding and production. Improving efficiency for solar energy utilization is a key to improve corn yield further under close planting condition. Fast chlorophyll fluorescence parameters can quickly and accurately detect light energy conversion efficiency. It plays an significant role in agricultural and economic development. Mapping of quantitative trait loci for chlorophyll fluorescence parameters is important for genetic mechanism of photosynthesis and marker-assisted selection in maize. In this study, genome wide association analysis (GWAS) and linkage analysis were used to explore the genetic architecture of chlorophyll fluorescence parameters in maize. The main results obtained were as follows:1.242 maize recombinant inbred lines were evaluated for eight chlorophyll fluorescence parameters. QTL mapping was performed using composite interval mapping. A total of 21 QTLs were found to be associated with chlorophyll fluorescence parameters in maize. QTLs in the interval could explain 5.41%-15.99% phenotypic variance and LOD value is 2.53-5.75.2. The chlorophyll fluorescence parameters in a panel of 404 maize inbred lines were investigated. Using 558629 high quality SNP evenly distributed across the maize genome, a genome-wide association analysis was performed to detect key SNPs associated with five chlorophyll fluorescence parameters. A total of 44 SNPs were identified for chlorophyll fluorescence parameters in BLUPs (the best linear unbiased predictions) based on a mixed linear model.8 SNP loci are significantly related to ETo/TRo,6 SNP loci are significantly related to ABS/CSo,18 SNP loci are significantly related to TRo/ABS,4 SNP loci are significantly related to ETo/CSo,5 SNP loci are significantly related to PIcs,3 SNP loci are significantly related to ABS/RC.3. The candidate gene GRMZM2G064949 was determined by bioinformatic analysis and gene expression analysis. A full-length cDNA sequence of GRMZM2G064949 was isolated from Zea mays by cloning technology. GRMZM2G064949 contained one ORF with 732bp, encoding 244 amino acids. The ORF sequence coding for maize GRMZM2G064949 gene was cloned into the over-expression vector pCAMBIA1300. The gene showed tissue-specific expression, without showing a clear feature of biochronometry.