, 2007). In fact, survival of bacteria in natural settings largely depends on its phenotypic plasticity, because altered phenotype Selleck Galunisertib influences the interaction of bacteria with its surrounding physicochemical environment, and thereby affects the ecological fitness of organism (Henderson et al., 1999; Palkova, 2004; Chantratita et al., 2007). Thus, from health as well as ecological perspectives, bacterial

genes involved in community establishment have received much attention. Pseudomonas alkylphenolia KL28 degrades 4-n-alkylphenol (C1–C5) using a novel catabolic pathway encoded by the lap catabolic gene cluster, which is distantly related to phenol and methyl-phenol-degrading genes of other Pseudomonas sp. (Jeong et al., 2003). This bacterium forms specialized aerial structures (SAS), which are beneficial for the utilization of vapor substrates and for survival under drying and starvation conditions. Under such conditions, P. alkylphenolia KL28 can survive for more than

a year and their SAS has been shown to form ultramicrocells by reductive division (Lee & Veeranagouda, 2009). In this study, a transposon mutant showing defect in SAS development was characterized to determine the gene(s) involved in SAS formation. Pseudomonas RAD001 alkylphenolia strain KL28 (Jeong et al., 2003) was cultured either in Luria–Bertani (LB) medium or in minimal salts basal (MSB) medium (Stanier et al., nearly 1966) with an appropriate carbon source. For growth on agar surfaces, cells were cultured on MSB or LB medium with 1.5% agar. Congo red (CR) at a final concentration of 80 mg L−1 was added to prepare LB-CR agar medium. The detailed culture

conditions for strains KL28 and Escherichia coli and the concentration of antibiotics for plasmid maintenance have been described previously (Yun et al., 2007). A KL28 transposon mutant library was generated using the transposon delivery vector pRL27 (Larsen et al., 2002), and disrupted genes were identified as described previously (Yun et al., 2007). Sequence homology between proteins was calculated using the bioedit program (http://www.mbio.ncsu.edu/BioEdit/page2.html). The nucleotide sequence identified in this study was deposited in the NCBI GenBank database and the accession number is HM172486. An in-frame ssg deletion mutant of KL28 was constructed by allelic replacement as described by Schafer et al. (1994). For this study, a gene fragment containing about 70% deletion of the internal region of ssg was created by overlap extension PCR as described previously (Ho et al., 1989). The primers used were dSsgFBHI, 5′-GGATCCTGGCCCATGACTGTT-3′, (BamHI, underlined); dSsgIR, 5′ GCCGATGCGCAGGTTGCGCTGATCGGC-3′; dSsgIF, 5′-GCGACCCTGGCGATCGGCAGCACCGGT-3′ and dSsgRSphI, 5′- GCATGCGGCTTCCAGTGTTCC-3′ (SphI, underlined).