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Zhong Z, Hu R, Zhao J, Liu W, Kwok LY, Sun Z, Zhang H, Chen Y. Acetate kinase and peptidases are associated with the proteolytic activity of Lactobacillus helveticus isolated from fermented food. Food Microbiol 2020; 94:103651. [PMID: 33279076 DOI: 10.1016/j.fm.2020.103651] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 09/16/2020] [Accepted: 09/25/2020] [Indexed: 11/18/2022]
Abstract
Lactobacillus (L.) helveticus is widely used in food industry due to its high proteolytic activity. However, such activity varies greatly between isolates, and the determining factors regulating the strength of proteolytic activity in L. helveticus are unclear. This study sequenced the genomes of 60 fermented food-originated L. helveticus and systemically examined the proteolytic activity-determining factors. Our analyses found that the strength of proteolytic activity in L. helveticus was independent of the isolation source, geographic location, phylogenetic closeness between isolates, and distribution of cell envelope proteinases (CEPs). Genome-wide association study (GWAS) identified two genes, the acetate kinase (ackA) and a hypothetical protein, and 15 single nucleotide polymorphisms (SNPs) that were associated with the strength of the proteolytic activity. Further investigating the functions of these gene components revealed that ackA and two cysteine peptidases coding genes (pepC and srtA) rather than the highly heterogeneous and intraspecific CEPs were linked to the level of proteolytic activity. Moreover, the sequence type (ST) defined by SNP analysis revealed a total of ten STs, and significantly weaker proteolytic activity was observed among isolates of ST2. This study provides practical information for future selection of L. helveticus of strong proteolytic activity.
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Affiliation(s)
- Zhi Zhong
- Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, Inner Mongolia Agricultural University, Hohhot, China; Key Laboratory of Dairy Products Processing, Ministry of Agriculture and Rural Affairs, Inner Mongolia Agricultural University, Hohhot, China; Inner Mongolia Key Laboratory of Dairy Biotechnology and Engineering, Inner Mongolia Agricultural University, Hohhot, China
| | - Richa Hu
- Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, Inner Mongolia Agricultural University, Hohhot, China; Key Laboratory of Dairy Products Processing, Ministry of Agriculture and Rural Affairs, Inner Mongolia Agricultural University, Hohhot, China; Inner Mongolia Key Laboratory of Dairy Biotechnology and Engineering, Inner Mongolia Agricultural University, Hohhot, China
| | - Jie Zhao
- Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, Inner Mongolia Agricultural University, Hohhot, China; Key Laboratory of Dairy Products Processing, Ministry of Agriculture and Rural Affairs, Inner Mongolia Agricultural University, Hohhot, China; Inner Mongolia Key Laboratory of Dairy Biotechnology and Engineering, Inner Mongolia Agricultural University, Hohhot, China
| | - Wenjun Liu
- Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, Inner Mongolia Agricultural University, Hohhot, China; Key Laboratory of Dairy Products Processing, Ministry of Agriculture and Rural Affairs, Inner Mongolia Agricultural University, Hohhot, China; Inner Mongolia Key Laboratory of Dairy Biotechnology and Engineering, Inner Mongolia Agricultural University, Hohhot, China
| | - Lai-Yu Kwok
- Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, Inner Mongolia Agricultural University, Hohhot, China; Key Laboratory of Dairy Products Processing, Ministry of Agriculture and Rural Affairs, Inner Mongolia Agricultural University, Hohhot, China; Inner Mongolia Key Laboratory of Dairy Biotechnology and Engineering, Inner Mongolia Agricultural University, Hohhot, China
| | - Zhihong Sun
- Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, Inner Mongolia Agricultural University, Hohhot, China; Key Laboratory of Dairy Products Processing, Ministry of Agriculture and Rural Affairs, Inner Mongolia Agricultural University, Hohhot, China; Inner Mongolia Key Laboratory of Dairy Biotechnology and Engineering, Inner Mongolia Agricultural University, Hohhot, China
| | - Heping Zhang
- Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, Inner Mongolia Agricultural University, Hohhot, China; Key Laboratory of Dairy Products Processing, Ministry of Agriculture and Rural Affairs, Inner Mongolia Agricultural University, Hohhot, China; Inner Mongolia Key Laboratory of Dairy Biotechnology and Engineering, Inner Mongolia Agricultural University, Hohhot, China
| | - Yongfu Chen
- Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, Inner Mongolia Agricultural University, Hohhot, China; Key Laboratory of Dairy Products Processing, Ministry of Agriculture and Rural Affairs, Inner Mongolia Agricultural University, Hohhot, China; Inner Mongolia Key Laboratory of Dairy Biotechnology and Engineering, Inner Mongolia Agricultural University, Hohhot, China.
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