MinD plays an important role in Aeromonas hydrophila adherence to Anguilla japonica mucus

• MinD gene is the new virulence gene, which is involved in Aeromonas hydrophila adhesion.
• Our results provide new information about the molecular mechanisms underlying the adhesion regulation of Aeromonas hydrophila.
• Complemented strain can purposefully study the function of MinD gene.

For a better understanding of the genitic regulation of the adhesion of Aeromonas hydrophila, a mini-Tn10 transposon mutagenesis system was introduced to generate an insertion mutant library by cell conjugation between the donor Escherichia coli Sm10 (pLOF/Km) and the recipient A. hydrophila strain W. Out of 332 individual colonies, 7 mutants with significantly attenuated adhesion ability were selected. The DNA sequence flanking the mini-Tn10 transposon inserted in the mutant strain M45 was amplified by TAIL-PCR. The results showed that an ORF of approximately 870 bp (GenBank accession number KP271930) of the mutant strain M45 was inserted by mini-Tn10. This ORF putatively encodes a deduced 289 amino acid protein that displays the highest identity (100%) with the CobQ/CobB/MinD/ParA family protein of A. hydrophila subsp. hydrophila ATCC 7966. The biological characteristics of the wild-type W, the mutant strain M45 and the complemented strain C45 were investigated. The results indicated that mutation of MinD gene in A. hydrophila could lead to abnormal cell division and reduce the ability of adhesion, biofilm formation and bacterial motility.