Insights into the Metabolites Conferring Pathogenicity of Xanthomonas oryzae and Its Inhibition by Trichoderma longibrachiatum EF5

Aims: The present study was aimed to evaluate the effect of volatile and soluble metabolites of Trichoderma longibrachiatum EF5 against Xanthomonas oryzae pv. oryzae, and to identify the metabolites produced by Xanthomonas oryzae pv. oryzae in culture filtrate.

Study Design: In vitro bioassay with CRD.

Place and Duration of Study: Biocatalysts laboratory, Department of Agricultural Microbiology, Tamil Nadu Agricultural University, Coimbatore, 2019-2020.

Methodology: Inverted plate, bipartite plate and agar well method was done under in vitro to observe the efficacy of T. longibrachiatum EF5 VOC against X. oryzae pv. oryzae. Analysis of Xanthomonas oryzae pv. oryzae metabolites by using Gas Chromatography and Mass Spectrometry (GC-MS).

Results: T. longibrachiatum EF5 VOC and metabolites completely inhibited the growth of X. oryzae pv. oryzae in inverted plate assay, whereas in bipartite and agar well diffusion assays unmeasurable growth of X. oryzae pv. oryzae was observed. The metabolites or Diffusible signal factors such as butyrolactone, propionic acid derivatives, phenyl acetic acid, hydrofurans, picoxystrobin, benzoic acid derivatives were produced by X. oryzae pv. oryzae in the growing medium. The role of these metabolites revealed that they are involved in pathogenicity, virulence, quorum sensing and the synthesis of antioxidant.

Conclusion: T. longibrachiatum EF5 volatile and soluble metabolites can be used as biocontrol agent against X. oryzae pv. oryzae.