The Gene Expression Modification And The Interacting Protein Screening Of Maize Bsd2 Mutant

Zea mays L., the annual herbaceous plant belongs to Gramineae Zea, has the highest world-wide production of all grain crops. In addition to its economical value, maize is a good model organism to study C4 genetics, physiology and development. It has a specialized anatomy structure, called Kranz structure, which is formed by two different type of cells-mesophyll cells and bundle sheath cells. The carbon assimilation is specially happened in the bundle sheath cells during photosynthesis, and then decrease the photorespiration. Taking advantage of this tissue specificity, maize has high photosynthetic efficiency. Therefore it has very important theoretical value and application prospect to explore the molecular mechanism of C4 regulation.Objective: The expression of BSD2 gene in Bundle sheath defective2 mutant is knocked out by the Mutator transposable element, which causes the changes of leaf morphology and photosynthesis. In order to reveal the molecular function of BSD2 gene, we performed RNA sequencing to monitor the transcrptome changes and yeast two hybrid to identify the interacting proteins.Method: The wild type maize seedling and bsd2 mutant were used as study marterials in our study. The leaf sections that in different developmental stages under different light intensity were harvested to extract RNA for RNA-Seq. Yeast two hybrid were perfomed using BSD2 protein as a bait following the instruction of clontech Company-Result and conclusion:1.The seedlings of bsd2 mutant are pale green and seedling lethal. The photosynthetic parameters, e.g. Fv/Fm, Fv'/Fm', (?)PS ? and ETR were significantly decreased in the mutants.2.Total of 24 RNA-Seq libraries were constructed and sequenced. After trimming adapters and filtering out low quality reads, we got 241M clean reads. The reads number of each sample is between 8,405,966 and 24,333,441, and about 180M reads were uniquely aligned to maize B73 AGPv3 genome. By comparing the transcription difference between wild type and bsd2 mutant, we identified 12,161 differential expression gene (DEGs), which mainly involoved in calvin cycle, major CHO metabolism, mitochondrial electron transport/ATP synthesis, and abiotic stress resistance pathways. The expression of core C4 shuttle genes, e.g. PPDK and NADP-ME were significantly down regulated, however, the stress resistance related genes, especially heat shock protein genes, were drameticaly induced in the bsd2 mutant.3.We screened out a putative interaction protein with BSD2 by yeast-two-hybrid, which is ferredoxin (Fd2) that involved in photosynthesis by mediating electron transferring.