Department of Plant Breeding, Physiology and Seed Science, University of Agriculture in Krakow, Łobzowska 24, 31-140 Krakow, Poland.
Moredun Research Institute, Pentland Science Park, Bush Loan, Penicuik EH26 0PZ, UK.
Int J Mol Sci. 2023 Jan 21;24(3):2174. doi: 10.3390/ijms24032174.
In this study, a new strain of , SRS89, was isolated from surface-sterilized stevia seeds. The isolate was evaluated using morphological, molecular, and biochemical methods. The bacterium was 1.5 μm long, yellowish in color, and classified as Gram-negative. Whole genome sequencing of our strain revealed the presence of a 4,610,019 bp chromosome, and genome annotation resulted in the detection of 4283 genes encoding 4204 putative coding sequences. Phylogenic analysis classified the genome of our strain close to the MP7 and LMG 24199 strains of . Functional analysis showed that the highest number of genes within the analyzed bacterium genome were involved in transcription, amino acid transport and metabolism, and carbohydrate transport and metabolism. We also identified genes for enzymes involved in the biosynthesis of carotenoids and terpenoids. Furthermore, we showed the presence of growth regulators, with the highest amount noted for gibberellic acid A, indole-3-acetic acid, and benzoic acid. However, the most promising property of this strain is its ability to synthesize rebaudioside A; the estimated amount quantified using reversed-phase (RP)-HPLC was 4.39 mg/g of the dry weight of the bacteria culture. The isolated endophytic bacterium may be an interesting new approach to the production of this valuable metabolite.
在这项研究中，从表面消毒的甜菊种子中分离出一种新的菌株，SRS89。该分离株通过形态学、分子和生化方法进行了评估。该细菌长 1.5 μm，呈黄色，归类为革兰氏阴性菌。我们菌株的全基因组测序显示存在一个 4,610,019 bp 的染色体，基因组注释结果检测到 4283 个基因，编码 4204 个推定的编码序列。系统发育分析将我们菌株的基因组归类为接近 MP7 和 LMG 24199 菌株的。功能分析表明，在所分析的细菌基因组中，参与转录、氨基酸运输和代谢以及碳水化合物运输和代谢的基因数量最多。我们还鉴定了参与类胡萝卜素和萜烯生物合成的酶的基因。此外，我们还证明了存在生长调节剂，其中赤霉素 A、吲哚-3-乙酸和苯甲酸的含量最高。然而，该菌株最有前途的特性是其能够合成甜菊苷 A；使用反相（RP）-HPLC 定量估计的量为 4.39 毫克/克细菌培养物的干重。这种内生细菌可能是生产这种有价值代谢物的一种有趣的新方法。
