| Puccinia striiformis f. sp. tritici, the causal fungus of wheat stripe rust, is an obligatebiotrophic basidiomycete. Urediniospores are the most common spore involved in theepidemiology of the disease.Tip growth of germ tubes of germinated urediniospores is a keystep during infection of wheat, and cytoskeleton plays an important role in mycelial growth.But few studies have investigated it to date. In this paper, we did research about the PsDLC8and PsACT1.The main results are as follows:The EST sequences of PsDLC8and PsACT1were checked out from the cDNA library,and then cloned the full cDNA sequence by RACE. The cDNA sequence of PsDLC8is569bp and the ORF encoded100amino acids; PsACT1is1666bp and the ORF encoded375amino acids.Compared to urediniospore, Real time PCR analysis showed that the expression ofPsDLC8was steady before96hpi, from144hpi to264hpi, PsDLC8was down-regulated.The minimum induction of PsDLC8occurred at216hpi, the transcripts were0.09fold overthat in urediniospore. PsACT1were down-regulated before12hpi and then very fewfluctuating from18to264hpiWhen expressed in Aspergillus nidulans, PsDLC8partially rescued the nudG mutant ingrowth and conidiophores, indicating that PsDLC8has similar functions with DLC8inAspergillus nidulans.Actin filament (F-actin) patterns were visualized microscopically during germ tubeformation. The most conspicuous actin-containing structures are actin patches. They weremainly concentrated near the hyphal tip and scattered throughout the cortex. By usingcytochalasin B, we observed that depolymerization of F-actin greatly reduced the germinationrate of urediniospores and disrupted the transport of vesicles to the germ tube tip, indicatingthat F-actin had a key role in the tip growth of P. striiformis f. sp. tritici.This work analysed functions of PsDLC8and PsACT1and initially determined the affecton growth of P. striiformis f. sp. Tritici. It helps us to understand the mechanism ofcytoskeleton in P. striiformis f. sp. Tritici. |
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