Abstract:Oomycetes is a class of diploid eukaryotic microorganisms in the kingdom of Chromista, including many of important plant pathogens. The principal impediment to progress in the molecular analysis of oomycetes has been the lack of efficient genetic and molecular biological tools. To evoke researchers to better understand the molecular genetics of oomycets and find out efficient tools for functional analysis of genes, three kinds of methods (disturbing gene expression, disrupting specific genes and spurring gene expression) used for the gene function analysis in oomycete study are reviewed in this paper. The review places an emphasis on the kind of disturbing gene expression. The advantages and disadvantages of the different techniques in three kinds were discussed. Future research trends of molecular genetics tools were discussed as well.