Analysis Of The Function Of Mts Genes From Different Myxobacteria

The marine myxobacterial has attracted the researcher's attention extensively since it has been found in 1998.For several years research,our laboratory has isolated many salt-tolerant myxobacterial from marine samples.And analysis of Myxococcus fulvus HW-1 in morphology,physiology and phylogeny has been carried out particularly.Then a genetic screen was performed in M.fulvus HW-1 and a mutant defect in S-molity had been identified,named Myxococcus fulvus HL-1.13 kb DNA sequence flanking the insertion site had been cloned and sequenced,and the 13 kb segment was predicted to contain six open reading frames,which likely form a gene cluster,named mts.In addition,the mutated mts genes led to serious defeat in social behavior,including S-molity,A-molity,fruiting-body formation,sporulation and cell-cell cohesion.But the effect of insertion and in-frame deletion of mtsC homologue in Myxococcus.xanthus DK1622 did not seem to be as strong as that of the insertion in mtsC in M.fulvus HW-1,only leading to weakly defect in S-molity and fruiting-body formation.In this work,in-frame deletion of each mts homologue except mtsC homologue was performed in DK1622,and the the phenotypes of these mutants indicated that mtsA,mtsB,mtsD,mtsE and mtsF homologues were all involved in S-motility and mtsA,mtsB,mtsD and mtsE homologues were required for development in M.xanthus. But the function of mts genes in HW-1 was much more important than those in DK1622.In order to study the difference function of mts genes between M.fulvus HW-1 and M.xanthus DK1622,we managed to translated the mts genes of HW-1 to DK1622 in-frame deletion mutants,and constructed a series of compensation strains.Then agglutination assay,motility phenotypes,developmental ability and adaption to the seawater were detected.In the previous experiment,the agglutination and motility ability did not significantly decreased by the in-frame deletion of mts genes.So,in this work,the compensation strains did not show obvious increase in agglutination and motility ability.But the fruiting body formation of the compensation strains was restored.So the mts genes in the compensation strains could function well.Considering that M.fulvus HW-1 was isolated from ocean sample,mts genes may function better in seawater condition.The motility and developmental ability of the compensation strains in seawater condition were detected.It is shown that the colony size of the strains decreased with the increase of the concentration of seawater, and there was no obvious difference between the compensation strains and the control. But the developmental ability of the compensation strains containing mts gene from HW-1 was enhanced obviously.First,strains containing mts gene from HW-1 finished aggregation 24h ahead of the control stains;second,in higher concentration of seawater(50%-60%),the developmental ability of strains containing mts gene from HW-1 was obviously strengthened.In all,in no seawater condition,there is no obvious difference between the mts gene from Myxococcus.fulvus HW-1 and these from Myxococcus.xanthus DK1622; but in seawater condition the mts gene from HW-1 can improve the developmental ability of DK1622 obviously.