The expression of at least one of these genes (PSPPH_4550) in temperature dependence had been previously observed with similar results [21]. In P. syringae pv. phaseolicola NPS3121, it has been suggested that NRPS genes are part of a genomic island (IG) acquired by horizontal transfer and is postulated to be involved in phaseolotoxin synthesis during peptide assembly. However, only the PSPPH_4550 gene has been demonstrated to have a role in this process [21]. Based on this hypothesis, the profile expression obtained for this group of genes at 18°C could be congruent

RG7422 with the differential expression of the Pht cluster genes and the conditions for phaseolotoxin synthesis. However, the RT-PCR results for the PSPPH_4547 gene showed that the expression of this gene is independent of temperature, presenting constitutive

behavior at both temperatures (Figure 3). Knowledge regarding the role of this P. syringae pv. phaseolicola gene group is limited and experimental work is still necessary. Likewise, is necessary to evaluate whether there is a relationship between these genes and phaseolotoxin synthesis genes, as has been previously proposed, or whether these genes participate in different biological processes that contribute to the fitness of the bacterium in low temperatures. In P. syringae pv. phaseolicola NPS3121, Small molecule library the Type VI secretion system (T6SS) is regulated by temperature Recently, a new secretion system has been recognized, called the Type Arachidonate 15-lipoxygenase VI secretion system (T6SS). This system is encoded within the genomes of most Gram negative bacteria, including plant, animal, and human pathogens, as well as environmental strains. The T6SS components are usually encoded by a gene cluster that is thought to form a genomic island whose composition and number varies among species [22–24]. The in silico analyses have revealed that the genome of P. syringe pv. phaseolicola 1448A carries only one putative T6SS gene cluster (HSI) that comprises the region from PSPPH_0119 to

PSPPH_0135. Furthermore, several genes putatively encoding some proteins of this system are scattered in the genome of this bacterium [24]. The microarrays results showed the induction of eight genes encoding proteins putatively involved in the T6SS in P. syringe pv. phaseolicola NPS3121 (Cluster 3). The PSPPH_0122 gene encodes a hemolysin-coregulated (Hcp) protein homolog, in addition to be an essential component of the secretion machinery, acts as an effector protein that is secreted through this system. The PSPPH_0124 gene encodes a hypothetical protein and the PSPPH_0125 gene encodes the IcmF protein, which in conjunction with the DotU protein (PSPPH_0126), act as associated structural proteins that anchor the secretion system in the cell membrane [25]. Within this cluster is also the PSPPH_0131 gene encoding the hsiG protein and the PSPPH_0135 gene that encodes a hypothetical protein.