Differential Expression Analysis Of Transcripts Of Mutant Male Inflorescence In White Birch (Betula Platyphylla Suk.) By CDNA-AFLP

White birch (Betula platyphylla Suk.), a monoecious species with unisexual flowers. It has certain value on landscaping, building materials, catering industry and pharmaceutical industry. We have previously found a natural mutant of male inflorescence showing significant features of male sterility, which had significantly abnormal structure and reproductive development compared to wild type male inflorescence.In order to reveal the developmental mechanism of the male inflorescence mutant, cDNA-amplified fragment length polymorphism (cDNA-AFLP) technology was conducted to identify candidate genes differentially expressed profiles in early and late development of mutant B.platyphylla male inflorescence.Obtained transcript-derived fragments (TDFs) were analysed by BlastX and bioinformatics analysis.According to the putative biological functions,certain TDFs related to flower development were verified by applying the quantitative real-time PCR technology.The expression was detected in different tissues and development stages. Gene functions were preliminary analysed.The major results were as follow:Pollen viability was determined examination by I2-KI and peroxidase method. The result indicated male mutant pollen viability was significantly lower than normal level, We speculated that the sterile sexuality may have changed.About4500polymorphic fragments (TDFs) were obtained in the early development of the birch male mutant by cDNA-AFLP analysis, including280differentially expressed fragments,81TDFs were recovered and submitted to the GenBank database (Accession Number: JK546624-JK546704). Homology analysis was conducted to the81TDFs by BlastX,51TDFs had lower or no homology in GenBank, they were regarded as new genes, the remaining30TDFs had high homology with known proteins (BlastX E-Value<e-10). These30TDFs were analysed by GO biological function and KEGG biological pathway analysis. The results demonstrated that these putative proteins were involved in catalytic activity, binding activity, signal transduction of biological regulation, biosynthesis and genes encoding transcription factors as well as the process of flower development, etc. Furthermore,5TDFs, MAP kinase, ubiquitin-conjugating enzyme, cellulose synthase. heat shock protein and cytochrome P450related to the development of male inflorescence were selected to detect the transcript expression profiles applying the quantitative real-time Real-time RT-PCR technology in different tissues and development stages of mutant male inflorescense.About5000polymorphic fragments (TDFs) were obtained in the late development of the birch male mutant by cDNA-AFLP analysis, including323differentially expressed fragments.141TDFs were sequenced and submitted to the GenBank database (Accession Number: JK546705-JK546845),among which88showed significant homology (BlastX E-Value<e-10) with known or putative proteins and TDFs reported from other plants. We presumed that the genes identified in the remaining53TDFs were new. These88TDFs were analysed by GO biological function and KEGG biological pathway analysis. The results demonstrated that these putative proteins were involved in signal transduction, protein export, stress response, energy metabolism, transcription, etc. We then selected10TDFs related to floral development, and determined their transcript expression profiles in different tissues by quantitative real-time reverse transcriptase-polymerase chain reaction.Comparing the different TDFs in early and late development of mutant B.platyphylla male inflorescence. In addition to the usually high expression of biological processes in the two stages (eg, metabolic processes, cellular processes, developmental processes, biosynthetic process, the process of biological regulation and stimulation processes), specific expression was found in early and late development of mutant respectively. These differentially expressed genes and their biological information laid the foundation for the further reveal of the birch male flower development and male sterility mechanism.