Hippophae rhamnoides L. rhizobacteria exhibit diversified cellulase and pectinase activities

Abstract

Hippophae rhamnoides L. provides an enormous range of medicinal and nutritional benefits. The significant abilities of this plant to survive in Himalayan high altitudes enticed our study to investigate its rhizosphere. Seventeen rhizobacterial strains were isolated from the rhizospheric soil and plant root nodules, belonging to genus Frankia, Azorhizobium, Bacillus, Paenibacillus, Brevibacillus and Pseudomonas, as identified by 16SrRNA sequencing. This varying bacterial population was further examined for the presence of root degrading enzymes pectinase and cellulase, which enable them to intrude the plant roots. Based on the growth and substrate utilization by these rhizobacteria on pectinase screening agar medium and Mandels and Reese agar medium, all the seventeen strains were identified as pectinase and cellulase producing rhizobacteria. The quantitative analysis by DNS method demonstrated varying enzyme activities, spot-lighting the physiological variation in the microbiome. The divergence in the enzyme activities shown by all the strains was analysed statistically, using the software ASSISTAT.

Keywords: Cellulase; Enzyme activity; Hippophae rhamnoides L.; Pectinase.

Fig. 1

Sketch showing root morphology of Hippophae rhamnoides

Fig. 2

Various root modification observed in Hippophae rhamnoidesa brown nodules; b white nodules and c root hair

Fig. 3

Cladogram of the isolated strains representing their relatedness (Uncultured Clostridium A1; Uncultured Clostridium A2; Bacillus subtilis A3; Bacillus A4; Bacillus A5; Bacillus A6; Bacillus cereus A7; Bacillus cereus A8; Azorhizobium caulinodans A9; Frankia F1; Frankia casuarinae F2; Frankia F3; Paenibacillus thermophilus R1; Brevibacillus R2; Pseudomonas R3; Azorhizobium R4 and Azorhizobium doebereinerae RC, respectively)

Fig. 4

Pectinase positive strain on PSAM plate (a) and cellulase positive strain on MRAM plate (b) by bacterial strains isolated from the root nodules and rhizospheric soil of Hippophae rhamnoides