Detection of Acylated Homoserine Lactone (AHL) in the Heterotrophic Bacteria Z-TG01 and Its Ecological Action on the Algae, Chlorella vulgaris

Abstract

Heterotrophic bacteria Z-TG01 was isolated from the phycosphere of Chlorella vulgaris and identified as Sphingomonas paucimobilis by VITEK 2 Compact automated system with an excellent confidence level (99.0% probability). We detected acylated homoserine lactones (AHL) bioactivity in the growth process of Z-TG01 using Agrobacterium tumefaciens KYC55. The effects of C. vulgaris on AHL bioactivity, as well as the mutual influence of C. vulgaris and Z-TG01 in a co-culture system, were investigated. Results showed that AHL bioactivity of bacteria Z-TG01 varied with the bacteria density and was inhibited by supernatants of C. vulgaris culture in the early and middle exponential phases within 2 h (p<0.01), and in the late exponential phase within 1.5 h (p<0.05 or p<0.01). Within a certain cell density, bacteria Z-TG01 and C. vulgaris promote mutual growth in a co-culture system.