Microarray-based Analysis Of Gene Differential Expression Of Maize Preharvest Sprouting

Preharvest sprouting is a phenomenon that seeds get germination before harvest in the maternal plants. As a global disease, the crops involved in the disaster are affected not only in the production but also in the qualities, storage and planting qualities. Rcently, the occurence of maize preharvest sprouting influenced inbred line breeding, application of cross breeding and hybrid seed production, made high loss of maize production, so it is necessary to do the further study. This study use A318 which is an inbred line and weaken dormancy as material to analyse the differential expressed genes of PHS by using the Affymetrix microarray. The results as follows:1. Identified in the field, the embryo of grains in PHS plants and normal plants were selected after 20 days of pollination to do the microarray analysis. Blast the unigene which ratio value is greater than 2 and less than 0.5 in the NCBI database, and preliminary analyse of differential expressed genes by bioinformatics, then classify the genes by their functions.Microarray results showed that 92 differential expressed genes were found based on standard of two times. Compared with the normal plants, two genes were up-regulated expression and 90 genes were down-regulated expression in PHS plants. Gene Ontology was used to classify the differential expressed genes according to their functions, most genes were related to transcription factors, protein metabolisms, carbohydrate metabolisms, adversity stresses, signal transductions, material transports, membranes, cytoskeletons and so on. According to the classification of three different GO angles,53.33% genes had molecular functions,28.89% genes were involved in biochemical processes and the rest genes were related to cellularity.2. Bioinformatic analysis was conducted and 14 genes in nine sorts which may be related to PHS were selected:Phosphoethanolamine methyltransferase, APETALA2/EREBP transcription factors family, Serine/Threonine protein kinases, dehydrin, late embryogenesis abundant protein, dormancy/auxin associated protein, ferredoxin-sulfite reductase mature protein, bHLH transcription factors family and WRKY transcription factors family. These genes affected maize PHS by participating in dormancy breaking, hormone metabolism pathway of ABA and GAs, acquisition of seed desiccation tolerance and enzymes metabolism process. 3. A total of nine genes were selected to conducted the verification experiments by real-time fluorescence quantitative PCR and the reaction processes were optimized. Specific bands were amplified in five genes:APETALA2/EREBP transcription factors family (Zm.80457), Phosphoethanolamine methyltransferase (Zm.217), dehydrin (Zm.10149), ferredoxin reductase mature protein (Zm.94307), bHLH transcription factors family (Zm.10120). Compared with normal plants, RTFQ-PCR results of these five genes expression trend after 20 days of pollination in PHS plants were consistent with the expression trend of micoarray, and other four genes were not amplified successfully.Above, in our research, several differential expressed genes of maize PHS were found by using microarray, RTFQ-PCR and bioinformatics. These results will lay a foundation for the expressed regulation of maize PHS key genes and teratogenic mechanisms.