Exploring the Potentials of Lysinibacillus sphaericus ZA9 for Plant Growth Promotion and Biocontrol Activities against Phytopathogenic Fungi

Abstract

There is an ongoing hunt for biologically active compounds that can combat phytopathogenic fungi and improve plant growth without causing any hazards to the environment. Consequently the present study aims at deciphering the plant growth promotion and antifungal capability of Lysinibacillus sphaericus ZA9. The bacterium was previously isolated and identified in our laboratory from maize rhizosphere using 16S rRNA gene sequencing. The test bacterium L. sphaericus ZA9 was found to produce high quantity of IAA (697 μg/ mL); siderophores (195.79 μg/ mL), HCN and hydrolytic enzyme as compared to the reference strain Bacillus sphaericus Z2-7. The bacterium was also capable of solubilizing silicates (Si), phosphates (P), and potassium (K). The bacterium enhanced the seedling vigor and germination of seeds pretreated with it and promoted the shoot length of both cucumber and tomato seeds in greenhouse experiment. L. sphaericus ZA9 and its cell free culture supernatant showed varied antagonistic behavior against Alternaria alternata, Curvularia lunata, Aspergillus sp., Sclerotinia sp., Bipolaris spicifera, Trichophyton sp. Fermentation broth culture of L. sphaericus ZA9 was then used to isolate antifungal metabolites by silica column chromatography. Identification and determination of antifungal compounds was carried out by Thin-layer chromatography (TLC) followed by NMR spectroscopy. Two compounds were isolated and identified as 2-pentyl-4-quinolinecarboxylic acid (C15H17NO2) which is a quinoline alkaloid and 1- methylcyclohexene which is a cycloalkene. Compound 1; 2-Penthyl-4-quinolinecarboxylic acid was found to be highly antagonistic against most of the fungi tested as compared to the bacterium itself. Its activity was comparable to that of fungicide Benlate, while compound 2; 1- methylcyclohexene did not show any antifungal activity.

Lysinibacillus sphaericusas a Nutrient Enhancer during Fire-Impacted Soil Replantation

“…e role of PGPB in this nutrient cycling consists of their capacity to synthesize organic acids, so that the consequent soil acidi cation can lead to phosphorus release from mineral phosphate, turning it into soluble and available forms for plants uptake [30,31]. Studies reported L. sphaericus solubilization activity in silicate medium agar and biochar, supporting our results [28,32]. Presumably, L.…”

Biocontrol of Bacterial Leaf Blight of Rice and Profiling of Secondary Metabolites Produced by Rhizospheric Pseudomonas aeruginosa BRp3

“…(especially the HAQs), and a routine silica column chromatography was failed to purify them. Although, Naureen et al (2017) have successfully purified the secondary metabolites (2-pentyl-4-quinolinecarboxylic acid and 1- methylcyclohexene) from Lysinibacillus sphaericus ZA9 but the chemistry of these metabolites is significantly different from the HAQs identified in the present study. A high-quality preparatory HPLC system may be required to purify various analogs of HAQs (Wang et al, 2011).…”

Aspergillus terreus Inhibits Growth and Induces Morphological Abnormalities in Pythium aphanidermatum and Suppresses Pythium-Induced Damping-Off of Cucumber

“…In addition, A. terreus produces glucanase enzyme and mevastatin, the activities of which are suggested to play a role in the antagonism against P. aphanidermatum . In addition to the active role of enzymes in biological control, several other secondary metabolites contribute effectively to the control of plant pathogens such as siderophore (Schwyn and Neilands, 1987; Naureen et al, 2017) and Hydrogen cyanide (HCN) (Ramette et al, 2003). Baakza et al (2004) indicated production of siderophore by Aspergillus species including A. terreus .…”