Acta Veterinaria et Zootechnica Sinica ›› 2022, Vol. 53 ›› Issue (4): 1241-1251.doi: 10.11843/j.issn.0366-6964.2022.04.024

• BASIC VETERINARY MEDICINE • Previous Articles     Next Articles

Expression Pattern Analysis of Related Genes in SWN Gene Cluster of Alternaria oxytropis Mutated by Ethyl Methylate

YU Yongtao1*, MAO Yanni1, ZHAO Qingmei2,3, LI Jinrong1, BAI Xiaonan1, XUE Jiaqi1, ZHANG Haodong1   

  1. 1. School of Agriculture, Ningxia University, Yinchuan 750021, China;
    2. College of Biological Science and Engineering, Beifang University of Nationalities, Yinchuan 750021, China;
    3. Key Laboratory of Fermentation Brewing Engineering and Biotechnology State Nationalities Affairs Commission, Yinchuan 750021, China
  • Received:2021-07-05 Online:2022-04-23 Published:2022-04-25

Abstract: The objective of this study is to investigate the correlation between the expression pattern of genes in swainsonine biosynthesis gene cluster (SWN) and swainsonine production in Alternaria oxytropis, fungal endophyte from locoweed. A. oxytropis UA003 was treated with Ethyl methanesulfonate (EMS). The SW content of each mutated strain was determined to screen strains with significant changes in SW yield. The expression levels of AATL, swnR, swnN, swnH1, swnH2, swnK (A, KS, SDRe1, SDR) in SWN gene cluster of some strains including A. oxytropis UA003, EMS mutagenesis strains and A. gansuense were analyzed. The swnK gene sequences of the above-mentioned strains were further analyzed to mutation sites. The results showed as follows: the yield of SW in E02, E23 and E25 strains induced by EMS was significantly increased, and the gene expressions of AATL, swnR, swnN, swnH1, swnH2 were significantly down-regulated (P<0.05 or P<0.01). The gene expressions of A, KS, SDR and SDRe1 were significantly up-regulated (P<0.05 or P<0.01 in all strains). E02 strain mutated by EMS had 13 nucleotide mutation sites of swnK gene and 6 amino mutation acid sites, respectively. Compared with UA003, EA strain had 163 different nucleotide sites and 67 different amino acid sites. The amino acid sequence MLTPAVSLKNLTKPK deletion was absent in the initial segment of the transcription product, and an amino acid sequence of TEVDGVP was inserted in the position 1135 and 1143 of the AT gene transcription product. In conclusion, EMS mutagenesis could significantly change the biosynthesis of swainsonine and gene expression of SWN gene cluster in A. oxytropis. The expression patterns of AATL, swnR, swnN, swnH1 and swnH2 genes in the SWN gene cluster were negatively correlated with the biosynthesis of swainsonine in E02, E23 and E25 strains. However, the expression patterns of A, KS, SDR and SDRe1 were positively correlated with the biosynthesis of swainsonine in above-mentioned strains. The biosynthesis changes of SW in endophytic fungi may be related to the structural and functional changes of related genes in SWN gene cluster.

Key words: fungal endophyte from locoweed, ethyl methanesulfonate mutagenesis, swainsonine, swainsonine biosynthesis gene cluster, gene expression

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