1. The heterologous expression and biological function of the Lactobacillus bacteriocin plantaricin K (PlnK) remain largely unknown.

2. In this study, PlnK was efficiently expressed in competent E. coli BL21 (used in transformation and protein expression) after 12 h, at 37°C and in 0.4 mmol/l isopropyl β- d-1-thiogalactopyranoside (IPTG).

3. The inhibitory bacterial spectrum of recombinant PlnK was investigated and indicated that levels of PlnK above 0.10 mg/ml produced an obvious inhibitory effect on gram-positive bacteria and gram-negative bacteria in vitro.

4. The effects of PlnK on intestinal immune function and the gut microbiome distribution in broilers were studied. The results revealed that, after consuming 2.50 × 10^˗3 mg/ml of PlnK in water for one week, at the phylum level, the abundance of Firmicutes was increased and the abundance of Bacleroidetes was decreased. At the family level, the abundance of Lachnospiraceae, Ruminococcaceae and Streptococcaceae were significantly improved, but the abundance of Bacteroidaceae was reduced. At the genus level, the abundances of Lachnoclostridium, Streptococcus and Ruminococcaceae-UCG-013, were significantly up-regulated, and the abundance of Bacteroides was down-regulated.

5. After oral liquid intake of PlnK for one week, levels of secretory immunoglobulin A (sIgA) in the duodenal mucus were not significantly increased, but the mRNA levels of TLR3, MDA5, IFN-α, IFN-β, IFITM3 and IFITM10 in the duodenum were significantly reduced.

6. This study demonstrated that the recombinant PlnK could adjust the intestinal microbiome distribution and downregulate the IFN pathway.

1.乳酸杆菌乳酸菌植物素K（PlnK）的异源表达和生物学功能仍然未知。

2.在这项研究中，在37°C和0.4 mmol / l异丙基β-d-1-硫代半乳糖吡喃糖苷（IPTG）中12小时后，PlnK在感受态大肠杆菌BL21中有效表达（用于转化和蛋白质表达）。

3.重组PlnK的抑制细菌光谱进行了调查，并表示上述0.10 PlnK的那个水平毫克/毫升制备革兰氏阳性菌和革兰氏阴性菌具有明显的抑制作用在体外。

4.研究了PlnK对肉鸡肠道免疫功能和肠道微生物组分布的影响。结果表明， 在水中以2.50× ^10˗3mg / ml的剂量摄入PlnK 1周后，在门的水平上，Firmicutes的丰度增加而Bacleroidetes的丰度降低。在家庭一级，  Lachnospiraceae，Ruminococcaceaceae 和 Streptococcaceceae 的丰度显着提高，而Bacteroidaceae的丰度  却降低了。在属的水平，丰度Lachnoclostridium，链球菌和Ruminococcaceae-UCG-013显着上调，而拟杆菌的含量下调。

5.口服PlnK一周后，十二指肠粘液中分泌性免疫球蛋白A（sIgA）的水平并未显着增加，但TLR 3，MDA 5，IFN-α，IFN-β，IFITM 3的mRNA水平十二指肠中的IFITM 10和IFITM 10显着降低。

6.这项研究表明重组PlnK可以调节肠道微生物组分布并下调IFN途径。