Mechanism of the Potential Therapeutic Candidate Bacillus subtilis BSXE-1601 Against Shrimp Pathogenic Vibrios and Multifunctional Metabolites Biosynthetic Capability of the Strain as Predicted by Genome Analysis

Abstract

The global shrimp industry has suffered bacterial diseases caused mainly by Vibrio species. The typical vibriosis, acute hepatopancreatic necrosis disease (AHPND), has resulted in mass mortality and devastating economic losses. Thus, therapeutic strategies are highly needed to decrease the risk of vibriosis outbreaks. Herein, we initially identified that the growth of the causative agent of AHPND, Vibrio parahaemolyticus (VP AHPND) and other vibrios in Pacific white shrimp (Litopenaeus vannamei) was inhibited by a Bacillus subtilis strain BSXE-1601. The natural products amicoumacins A, B, and C were purified from the cell-free supernatant from the strain BSXE-1601, but only amicoumacin A was demonstrated to be responsible for this anti-Vibrio activity. Our discovery provided the first evidence that amicoumacin A was highly active against shrimp pathogens, including the representative strain VP AHPND. Furthermore, we elucidated the amicoumacin A biosynthetic gene cluster by whole genome sequencing of the B. subtilis strain BSXE-1601. In addition to amicoumacin A, the strain BSXE-1601 genome harbored other genes encoding bacillibactin, fengycin, surfactin, bacilysin, and subtilosin A, all of which have previously reported antagonistic activities against pathogenic strains. The whole-genome analysis provided unequivocal evidence in support of the huge potential of the strain BSXE-1601 to produce diverse biologically antagonistic natural products, which may facilitate further studies on the effective therapeutics for detrimental diseases in shrimp.

Benefits of Polyphenol-Based Synbiotics in Crustacean Diet

“…In this study, the dose established for L. reuteri is in accordance with the literature data regarding the administration of probiotics belonging to the Lactobacillus genus in crustaceans [88][89][90][91]. Furthermore, for B. clausii, the doses selected are in agreement with previous studies conducted using probiotics of the Bacillus genus in finfish and shellfish diets [7,90,92,93]. It is worth noting that the presence of OLE may have exerted a double action.…”

Biocontrol Ability and Mechanism of a Broad-Spectrum Antifungal Strain Bacillus safensis sp. QN1NO-4 Against Strawberry Anthracnose Caused by Colletotrichum fragariae

“…According to morphological characteristics as well as genome alignment, strain QN1NO-4 was identified as a novel species of the genus Bacillus (Table 1, Figure 2 and Supplementary Tables 3, 4). As potential biocontrol agents, Bacillus species had also been successfully used to control other post-harvest diseases of different fruit, such as Bacillus species against B. cinerea and green mold in strawberry fruit and citrus (Tian et al, 2020;Wang et al, 2021), B. amyloliquefaciens against Penicillium in oranges and apples (Calvo et al, 2017;Wang et al, 2020;Ye et al, 2021), and B. atrophaeus against anthracnose on soursop and avocado (Guardado-Valdivia et al, 2018).…”

“…Especially, the Bacillus genera were evaluated as outstanding biocontrol agents against fungal pathogens, such as Bacillus halotolerans against Botrytis cinerea in strawberry fruit (Wang et al, 2021;Ye et al, 2021), Bacillus sp. w176 against post-harvest green mold in citrus (Tian et al, 2020), Bacillus atrophaeus against anthracnose in soursop and avocado (Guardado-Valdivia et al, 2018), and Bacillus amyloliquefaciens against other phytopathogens of fruits (Calvo et al, 2017;Gotor-Vila et al, 2017;Wang et al, 2020;Ye et al, 2021). Several Bacillus spp.…”

Evaluation of Potential Probiotic Properties of a Strain of Lactobacillus plantarum for Shrimp Farming: From Beneficial Functions to Safety Assessment

“…The antagonistic activity of W2 was evaluated using the agar diffusion method (Oxford cup method) ( Kuang et al, 2018 ). The selected indicator bacteria were 7 common aquatic pathogenic strains, including V. vulnificus S01P2, V. splendidus BSD11, V. harveyi SRTT9 ( Wang et al, 2020 ), V. parahaemolyticus 20130629002S01 ( Dong et al, 2017 ), Streptococcus iniae NUF849 ( Sheng et al, 2018 ), Aeromonas hydrophila AP40301 ( Xu et al, 2018 ), and Shewanella marisflavi AP629 ( Li et al, 2010 ). The culture methods of W2 and pathogens were similar to those described in the adhesion assay.…”