Full-Length CDNA Cloning And Bioinformatic Analysis Of Chloroplast Signal Recognition Particle And G-Protein Genes In Wheat

Stripe rust is one of the most important diseases of wheat worldwide. In the past years, the research mainly focused on the cytology and histopathology of the interaction mechanism of wheat and Puccinia striiformis f. sp. tritici. However, less was known on the molecular level. In our laboratory, a suppression subtractive hybridization (SSH) cDNA library of wheat cultivar Suwon11 induced by Puccinia striiformis Chinese race CY23 was constructed. 2,167ESTs which were subsequently assembled and categorized were obtained with high quality. Herein, a chloroplasts signal recognition particle and a GTP-binding protein TypA (tyrosine phosphorylated protein A) genes, which were picked from the SSH cDNA library, were cloned using RACE (Rapid Amplification of cDNA Ends) technology. To further understand the molecules and their function in the interaction of stripe rust fungus and wheat, bioinformatic analysis and expression profile analysis were performed.Using RACE technique in combination with RT-PCR, a 1725bp cDNA sequence designated as TAFFC, was obtained from wheat. Sequence analysis showed that TAFFC contains a complete 1446bp ORF encodes a putative protein composed of 481 amino acids. The deduced amino acid sequence contained three conserved structures and was homologous to the cpSRP54 in Oryza sativa, Pisum sativum, Arabidopsis thaliana and Vitis vinifera. The results of real-time PCR analysis revealed that TAFFC transcripts were steady in incompatible interaction of wheat and stripe rust, whereas down-regulated in compatible interaction. It is spculated that after wheat infected by Puccinia striformis the transports of chloroplasts protein had been infected and thereby the photosynthesis of wheat will be affected.TATYPA, which encoded a polypeptide of 675 amino acids with four conserved motifs, was 2512bp in length. Phylogenetic tree indicated that TATYPA might share a common ancestor with other TypA type of G protein genes which contained four conserved TypA type G protein motifs in Oryza sativa,Populus trichocarpa,Trifolium pretense,Suaeda salsa,Vitis vinifera and Arabidopsis thaliana. The results of real-time PCR showed that the transcription profile of TATYPA, which were steady in the the compatible interaction; whereas in the incompatible interaction were down-regulated before 24h and became up-regulated in the later stage. It was speculated that the transcription of TATYPA, as a translational regulator of the stress-responsive proteins involved in ROS, was induced in the interaction of stripe rust fungus and wheat.