RESUMO
Increasing the yield of maize F1 hybrid is one of the most important target for breeders. However, as a result of the genetic complexity and extremely low heritability, it is very difficult to directly dissect the genetic basis and molecular mechanisms of yield, and reports on genetic analysis of F1 hybrid yield are rare. Taking F1 hybrid as the research object and dividing the yield into different affect factors, this approach may be the best strategy for clarifying the genetic mechanism of yield. Therefore, in this study, a maize F1 population consisting of 300 hybrids with 17,652 single nucleotide polymorphisms (SNPs) markers was used for genome-wide association study (GWAS) to filtrate candidate genes associated with the four yield-related traits, i.e., kernel row number (KRN), kernel number per row (KNPR), ear tip-barrenness (ETB), and hundred kernel weight (HKW). Combined with the results of previous studies and functional annotation information of candidate genes, a total of six candidate genes were identified as being associated with the four traits, which were involved in plant growth and development, protein synthesis response, phytohormone biosynthesis and signal transduction. Our results improve the understanding of the genetic basis of the four yield-related traits and may be provide a new strategy for the genetic basis of maize yield.
Assuntos
Estudo de Associação Genômica Ampla , Polimorfismo de Nucleotídeo Único , Zea mays , Zea mays/genética , Zea mays/crescimento & desenvolvimento , Fenótipo , Locos de Características Quantitativas , Genes de PlantasRESUMO
KEY MESSAGE: A novel strong fertility restorer gene Rf12 for C-type cytoplasmic male sterility of maize was finely mapped on chromosome 2. Its best candidate gene Zm00001d007531 is predicted to encode a p-type PPR protein. The lack of strong restorer gene of maize CMS-C greatly limits its application in hybrid seed production. Therefore, the cloning of maize CMS-C novel strong restorer genes is necessary. In this study, a strong restorer line ZH91 for maize CMS-C was found, and the novel restorer gene named Rf12 in ZH91 had been mapped in a 146 kb physical interval on maize chromosome 2. Using the third-generation high-throughput sequencing (ONT), the whole genome sequence of ZH91 was got, and with integrating the annotation information of the reference genome B73_RefGen_v4 and B73_RefGen_v5, four candidate genes were predicted in ZH91 within the mapping region. Then using gene cloning, stranded specific RNA sequencing, qRT-PCR analysis and subcellular localization, Zm00001d007531 was identified as the most likely candidate gene of Rf12. Zm00001d007531 encodes a p-type PPR protein with 19 PPR motifs and targets mitochondria and chloroplast. Stranded specific RNA sequencing and qRT-PCR results both show that the expression of Zm00001d007531 between anthers of near-isogenic lines C478Rf12Rf12 and C478rf12rf12 was significantly difference in pollen mother cell stage. And the result of sequence alignment for Zm00001d007531 gene in 60 materials showed that there are twelve SNPs in CDS region of Zm00001d007531 were tightly linked to the fertility. The finding of a novel strong restorer germplasm resource ZH91 for maize CMS-C can greatly promote the application of maize CMS-C line in maize hybrid seeds production, and the identification of candidate gene Zm00001d007531 can accelerate the backcrossing process of maize CMS-C strong restorer gene Rf12 to some extent.
Assuntos
Infertilidade das Plantas , Zea mays , Zea mays/genética , Infertilidade das Plantas/genética , Citoplasma , Fertilidade , Estudos de Associação GenéticaRESUMO
The callose synthase enzyme genes (Cals) generally plays an important role in resisting to environmental stresses as well as in regulating the microspore development of higher plant. However till now, few researches about ZmCals genes have been reported in maize. In this study, ten ZmCals genes were identified, and they are distributed on four chromosomes in maize. All ZmCals proteins contain Glucan-synthase-domain and Fks1-domain. RNA-seq data from public databases were analyzed and the result suggested that ZmCals involved in the development of various tissues, and a strong expression presented especially in young tissue. qRT-PCR analysis shown that most of ZmCals are highly expressed in root, stem and leaf at jointing stage (V6 stage) with maize inbred line B73. Seven out of 10 ZmCals genes display higher expression during maize anther development especially from stage 6 to stage 8b, the dynamic accumulation process of callose is also observed during these period with aniline blue staining. Above results indicated multiple ZmCals may participate in the deposition of callose in maize anther. Therefore, ZmCals are necessary not only for reproductive organ but also for nutritive organ during maize growth and development. This study lays certain foundation for further investigating the roles of the callose synthase enzymes genes in maize.