Abstract: BS2 protein is derived from Bacillus subtilis B111 with strong resistance to Verticillium wilt. It can inhibit the spore germination of Verticillium dahliae and destroy its mycelial growth. The full length of BS2 gene is 1 566 bp, and it has 522 codons. Because of the difference of preferred codons,  if it is directly introduced into plants without optimization it will result in low or no expression of genes. The BS2 was optimized according to plant optimal synthesis, and 332 codons were optimized. The bioinformatics analysis showed that 1～28 amino acids composed a N-terminal signal peptide ; the mature BS2 protein was composed of amino acids 224～521 and was a neutral zinc metal peptidase. The subcellular localization maped the BS2 protein to the cell membrane. By Oxford Cup method,  the crude protein extract of transgenic tobacco lines showed strong antibacterial activity. It was founded that the  control group without infestation of Verticillium dahliae, the growth of the wild type and transgenic plants was basically the same, the phenotype was not significantly different, while under infection group of Verticillium dahliae V991, the phenotypic traits of transgenic tobacco were significantly better than wild type, the activity of SOD, CAT and content of SA, ABA in transgenic tobacco were higher than those in wild type tobacco. So, the BS2 gene could significantly improve the resistance of transgenic tobacco to Verticillium wilt.

Key words: BS2, bioinformatics analysis, transgenic tobacco, resistance to Verticillium wilt

摘要： BS2蛋白来源于枯草芽孢杆菌B111，具有较强的黄萎病抗性，能抑制黄萎病菌孢子萌发并破坏其菌丝生长。BS2基因全长1 566 bp，共522个密码子，由于物种间偏爱密码子的差异，若不对其进行密码子优化而直接导入植物，会造成基因表达量低甚至不表达。按植物密码子对BS2基因进行优化合成，共优化了332个密码子；生物信息学分析得出：1~28位氨基酸为N端信号肽，成熟的BS2蛋白由224~521位氨基酸构成，是一种中性锌金属肽酶；亚细胞定位将BS2蛋白定位于细胞膜；牛津杯法检测得出转基因烟草株系的蛋白粗提液有很强的抑菌活性；未侵染黄萎病菌的对照组，T1代转基因植株与野生型长势基本一致、表型无明显差异；黄萎病菌V991侵染组，转基因烟草的表型性状明显优于野生型，且两组中转基因烟草的SOD、CAT活性和SA、ABA含量均显著高于野生型，说明BS2基因可以显著提高转基因烟草的黄萎病抗性。

关键词: BS2, 生物信息学分析, 转基因烟草, 黄萎病抗性