Evaluation of multifarious plant growth promoting traits, antagonistic potential and phylogenetic affiliation of rhizobacteria associated with commercial tea plants grown in Darjeeling, India

Abstract

Plant growth promoting rhizobacteria (PGPR) are studied in different agricultural crops but the interaction of PGPR of tea crop is not yet studied well. In the present study, the indigenous tea rhizobacteria were isolated from seven tea estates of Darjeeling located in West Bengal, India. A total of 150 rhizobacterial isolates were screened for antagonistic activity against six different fungal pathogens i.e. Nigrospora sphaerica (KJ767520), Pestalotiopsis theae (ITCC 6599), Curvularia eragostidis (ITCC 6429), Glomerella cingulata (MTCC 2033), Rhizoctonia Solani (MTCC 4633) and Fusarium oxysporum (MTCC 284), out of which 48 isolates were antagonist to at least one fungal pathogen used. These 48 isolates exhibited multifarious antifungal properties like the production of siderophore, chitinase, protease and cellulase and also plant growth promoting (PGP) traits like IAA production, phosphate solubilization, ammonia and ACC deaminase production. Amplified ribosomal DNA restriction analysis (ARDRA) and BOX-PCR analysis based genotyping clustered the isolates into different groups. Finally, four isolates were selected for plant growth promotion study in two tea commercial cultivars TV-1 and Teenali-17 in nursery conditions. The plant growth promotion study showed that the inoculation of consortia of these four PGPR isolates significantly increased the growth of tea plant in nursery conditions. Thus this study underlines the commercial potential of these selected PGPR isolates for sustainable tea cultivation.

Evaluation of plant growth promotion properties and induction of antioxidative defense mechanism by tea rhizobacteria of Darjeeling, India

“…2 ). Previous studies have shown that the cultivable rhizobacterial population in the tea rhizosphere is dominated by Bacillus genera 12 , 14 , 15 , 49 . Moreover, Bacillus genera are a dominant cultivable member in the rhizosphere soil of different plants, e.g., rice, wheat, tobacco, Panax notoginseng (Chinese ginseng), etc.…”

Silencing of Phytopathogen Communication by the Halotolerant PGPR Staphylococcus Equorum Strain EN21

“…isolated from halophytes have been extensively studied [55], very little is known about the bacterium S. equorum. Also, while PGP activity in the bacteria S. cohnii, S. capitis and S. warneri of the genus Staphylococcus has previously been described [56], to our knowledge, only two studies have characterized this activity in S. equorum strains Se1 and Se2 isolated from halophytes in Arabidopsis thaliana, which showed an increase in weight and root length [57,58].…”

Phylogenetic and Functional Characterization of Culturable Endophytic Actinobacteria Associated With Camellia spp. for Growth Promotion in Commercial Tea Cultivars

“…The tea clones were treated with 10 ml cell suspension by soil drenching at one-month intervals for three months and watered with sterile distilled water daily (Liotti et al, 2018;Zhao et al, 2018). All vegetative parameters such as shoot length, root length, shoot fresh and dry weight and root fresh, dry weight, chlorophyll content and soil parameter analysis were recorded and compared to control (Dutta et al, 2015b;Dutta and Thakur, 2017).…”

“…To date, rhizospheric and endophytic PGP bacteria have been explored and characterized from C. sinensis (Dutta et al, 2015b;Nath et al, 2015;Dutta and Thakur, 2017). However, very few data are available on tea endophytic actinobacteria especially in the North East region of India.…”