Antibacterial and plant growth promoting attributes of Limosilactobacillus sp. MYSN3 isolated from noni fruit

Abstract

The aim of the study was to determine the antibacterial, plant growth promotion and bio-control activity of Limosilactobacillus sp. MYSN3 isolated from noni fruit (Morinda citrifolia). The noni fruit yielded eight distinct isolates and one effective isolate MYSN3 was chosen considering their antibacterial activity for further studies. The isolate MYSN3 recorded good inhibitory effect toward the tested plant pathogenic bacteria. The CFS of MYSN3 showed 69.12, 69.98 and 63.60 % inhibition against, Pectobacterium carotovorum sub sp. carotovorum, Ralstonia solanacearum and Xanthomonas oryzae pv. oryzae respectively in microplate assay. The isolate MYSN3 was identified as Limosilactobacillus sp. with accession number OL347895 and was verified using 16sRNA gene sequencing and had 95.23 % similarity with the earlier deposited sequence of Limosilactobacillus sp. - KJ865402. The effective isolate MYSN3 was characterized for growth promotion in plants and biological control attributes. Isolate MYSN3 showed IAA production (35.18 µg/ml), gibberellic acid production (23.45 µg/ml), solubilization of phosphate, potash, zinc and silicon and gave positive outcomes for protease and siderophore production and negative for cellulose degradation activity, HCN production activity and amylase activity. Seed treatment with Limosilactobacillus sp. MYSN3 greatly enhanced the standard of seed germination and seedling vigour of tomato by paper towel method and significantly increased plant height of tomato, chilli and okra under glasshouse condition when compared to control. The findings of the current research revealed that isolated Limosilactobacillus sp. MYSN3 possess promising antibacterial activity, plant growth promoting characteristics and bio-control traits. The potentiality of the isolate as bioinoculants and bio-control agents deserves further investigation.