A study of antibacterial efficacy of Tetraselmis rubens extracts against tomato phytopathogenic Pseudomonas corrugata

Abstract

This study investigated the antibacterial efficacy of extracts from the microalgae Tetraselmis rubens both in vitro and in vivo against the tomato plant pathogen Pseudomonas corrugata. Initially, the microalgae strain was identified by partial sequencing of the 18S rDNA. Then, in vitro experiments were conducted to evaluate the antibacterial properties of chloroform, methanol, and ethyl acetate extracts of T. rubens against P. corrugata. Subsequently, in vivo experiments assessed the preventive efficacy of these extracts against P. corrugata infection in juvenile tomato plants. The active components in the chloroform extract were analyzed using GC‐MS. The chloroform extract exhibited the most potent in vitro inhibitory impact on P. corrugata, resulting in inhibition zones of 31.33±2.02 mm. Additionally, the in vivo experiments confirmed the high antibacterial activity of T. rubens chloroform extract against P. corrugata when applied as preventive treatment. It reduced the incidence of bacterial spot disease to 5.61% of affected leaves, compared to a 41% infection rate in the positive control and 3% in the negative control.

The chloroform extract of T. rubens contained 15 chloroform-soluble compounds, as indicated by the GC‐MS analysis. These compounds fell under a variety of chemical categories, with a relative abundance of fatty acid esters. The antibacterial activity of these compounds has been demonstrated in previous studies and holds potential for further investigation and optimization for agricultural applications. This innovative study highlighted the potential of T. rubens extracts in developing sustainable solutions for managing infection of tomato plants with P. corrugata.