Indole acetic acid and lipopeptide-producing endophytic bacteria fromTaxus chinesis: toxicity evaluation of metabolic products

Abstract

48Endophytes play an important role in plant growth and development. Some one can 49 produce auxins, ACCs, iron carriers, and so on to help plants grow and resist unhealthy 50 growth environments. In addition, they can produce certain antimicrobial substances to 51 resist pests and diseases. Among them, Bacillus is the most common beneficial endophytic 52 bacterium in plants. In this paper, 20 IAA-producing strains were screened from 53 endophytic bacteria isolated from Taxus chinensis var. mairei plant tissues by high-54 performance liquid-chromatography (HPLC). Based on the 20 IAA-producing strains, 55 LC-TOF-MS technology was used to screen lipopeptide-producing Bacillus sp. As a result, 56 three strains (KLBMPTC01, KLBMPTC10, and KLBMPTC29) of Bacillus-producing 57 lipopeptides with abundant contents and species were obtained. According to the situation 58 of the IAA and lipopeptides produced by these strains, KLBMPTC10 was selected as the 59 experimental strain for later toxicological tests. In an Ames test and oral toxicity 60 experiments in mice, we did not detect mutagenicity and other physiological toxicity. This 61 is hoping to provide a theoretical basis for forest resource protection and biofertiliser 62 production therewith.63