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RsmA is a highly conservative global regulator in Pseudomonas, which could affect mRNA stability or control the translation of the target gene, and then to affect protine expression by combining mRNA of the target gene. in nitrogen-fixing Pseudomonas stutzeri A1501, there were one rsmA homologus gene and one non-coding small RNA gene rsmZ that might regulate RsmA activity. The evolution of RsmA and RsmZ in A1501 and conducted additional studies on their expression indicated that RsmA of A1501 shared 98% genetic similarity with RsmA of Pseudomonas aeruginosa PA01 and RsmZ contained 4 RsmA binding sites. The real-time PCR results showed that the rsmA transcription level was high in early growing period and droped down in the exponential growing and stable phases. The expression of rsmZ did not change significantly during the whole growing period. Under carbon starvation conditions, rsmA and rsmZ genes significantly reduced level of transcription. The mutation of rpoS did not affect rsmA expression; however, rsmZ transcription was enhanced by 30-fold, indicating that rsmZ was negatively regulated by rpoS. Further study indicated that there were no changes in the expression of rsmA and rsmZ in gacA mutant. Based on the above experiments, the regulatory model of rsmA and rsmZ in A1501 was different from other Pseudomonas, such as Pseudomonas fluorescens CHAO and Pseudomonas aeruginosa PA01. This paper has laid a theoretical foundation for further studying rsmA function and its regulatory mechanism under spesific condition. [ABSTRACT FROM AUTHOR]

In this study, cucurbits powdery mildew in the Zhoukou region of Henan province were identified and analysed, the results provided the basis for pathogen de-fence and systematic evolution. In order to identify the pathogen, the characteristics of histological morphological, molecular identification of ribosomal DNA internal tran-scribed spacer (ITS) and phylogenetic trees were conducted. The results indicated that the cucurbits powdery mildew in Zhoukou belonged to Sphaerotheca fuliginea. Phyloge-netic tree revealed that the differences between cucurbits powdery mildew and legumes, verbena hybrida, medusagyne oppositifolia powdery mildew were small, meanwhile the pathogen of Zhoukou was highly conserved with USA, Japan, Australia and UK. We speculated that the evolution of cucurbits powdery mildew may not be directly related to areas but to its own physiological race. [ABSTRACT FROM AUTHOR]