Plant Beneficial Features and Application of Paraburkholderia sp. NhPBG1 Isolated from Pitcher of Nepenthes hamblack

Pitchers are the unique structures of carnivorous plants used for the trapping of insects and other small invertebrates. The digestion of captured prey here is assisted by the bacteria, which have been associated with pitchers. These bacterial communities can therefore expect to have a variety of plant beneficial functions. In this study, the bacterial isolate NhPBG1 from the pitcher ofNepenthes hamblackwas screened for activity againstPythium aphanidermatum,Rhizoctonia solani,Fusarium oxysporum, andColletotrichum accutatumand was found to have the inhibitory activity towards all the tested phytopathogens. Interestingly, the isolate was found to have hyper-inhibitory effect againstP. aphanidermatum. Further to this, the isolate was also shown to be positive for plant beneficial traits such as indole-3-acetic acid (IAA) and ammonia production, phosphate, potassium and zinc solubilization, nitrogen fixation, and 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity. BLAST analysis of the 16S rDNA sequence of NhPBG1 has identified it asParaburkholderiasp. Also, theZingiber officinalerhizome pre-treated with NhPBG1 was found to get protected fromP. aphanidermatuminduced infection, whereas the control showed symptoms of infection. This was further confirmed by the microscopic evaluation of the presence of fungal mycelia in the tissues of control. However, the mycelial invasion could not be detected in the NhPBG1 treated rhizome. The metabolite profiling of NhPBG1 by GC-MS has identified variety of general metabolites, while the antifungal compounds pyocyanin and 1-hydroxyphenazine could be identified by the LC-MS/MS analysis.

Automated summary

Pitchers of carnivorous plants are unique structures used for trapping insects and other small invertebrates, assisted by bacterial communities that have beneficial functions for plants. The bacterial isolate NhPBG1 from Nepenthes hamblack pitcher shows inhibitory activity against various phytopathogens and positive plant beneficial traits. Pre-treatment with NhPBG1 protects Zingiber officinale rhizome from pathogenic infection, with metabolite profiling revealing antifungal compounds pyocyanin and 1-hydroxyphenazine.