Construction Of Stripe Rust Haustoria-isolating System And Function Analysis Of PsBpp1

Puccinia striiformis f.sp. tritici (Pst) are obligate fungi that form specialized infectionstructures hausoria after penetrating the host. Haustoria are the only infection structuresproduced inside the host cells that uptake nutrient from the host cell and interact with host insignal transduction. Therefore, research on haustoria metabolism plays decisive role inelucidating the pathogenic mechanism of stripe rust.For this reason,, we constructed the method for stripe rust haustoria isolation, bywhich we successfully isolated intact stripe rust haustoria with high purity. And this will lay agood foundation for accurately analyzing the genes with unique expression level in haustoria.Besides, this paper have given some explanations about the isolation and identification of a Gprotein beta subunit gene PsBPP1; other than that, we analyzed the transcriptional profiling ofPsBPP1in the interaction process between wheat and Pst by qRT-PCR; And thedifferentiation of PsBPP1amino acid sequences in the different races of rust fungi were alsoreported.; In addition, we described the gene potential function of PsBPP1bycomplementation of the Ustilago maydis mutant. The results are as follows:1、This study has established a Column chromatography method for isolation of Pst haustoriafrom wheat leaves seriously infected by Pst and observed the morphology of the isolatedhaustoria by microscope. The results we showed that the isolated haustoria were intact so asto confirm that this method is an effective way for isolation of Pst haustoria.2、The coding cDNA sequence of G protein beta subunit gene (PsBPP1) from Pst were firstlycloned by3’-RACE. The coding cDNA sequence is1038bp encoding a putative proteincomposed of345amino acids. Bio-informatics analysis showed that the amino acids containseven WD40repeats which combine together to form WD40domain.The coding DNAsequence of PsBPP1is1138bp comprising of4extrons and3introns.3、Real time RT-PCR analysis showed that PsBPP1was up-regulated at early stage ofinfection and the maximum induction of PsBPP1occurred at12hpi when the transcripts were1.62fold over that in urediniospore. The accumulation of transcripts decreased after12hpi.The accumulation of transcripts decreased obviously after36hpi lower than that inurediniospore, especially at96hpi, the accumulation of transcripts was just ten percent of thatin urediniospore. This showed that PsBPP1functions in the early stage of the interaction between Pst and wheat. Sequence analysis of PsBPP1in different stripe rust race CYR23,CYR31, CYR32and Pakistan No.1showed that there were no obvious differentiations withonly one changeable location.4、The complementation of Ustilago maydis mutant by PsBPP1showed that PsBPP1canpartly complement the growth speed and the budding growth of Ustilago maydis mutant.PsBPP1might be essential for infectious growth in stripe rust fungi.