Diversity and metabolic potential of culturable bacteria from the rhizosphere of Turkish tea grown in acidic soils

Abstract

The purpose of this study was to investigate the diversity of cultivable phosphate solubilising (PSB) and total bacteria originated from 384 rhizospheric acidic soils samples of tea plants grown at 32 locations. Over 900 rhizoplane bacteria were randomly selected from agar-solidified trypticase soy broth, and identified using fatty acid methyl ester (FAME) profiles. Based on FAME profiles, 53 bacterial genera were identified with a similarity index >0.3, but 60.3% of the identified isolates belonged to five genera: Bacillus (34.6%), Pseudomonas (8.9%), Stenotrophomonas (6.1%), Paenibacillus (5.9%) and Arthrobacter (4.8%). The bacilli group comprised many different species, with the most abundant being B. cereus, B. megaterium and B. sphaericus. The main identified Pseudomonads included P. fluorescens, P. putida, and P. alcaligenes. About 30.4% of the bacterial isolates could not be classified to genus since their similarity indices were <0.3 indicating no close matches. Most of the total and P-solubilizing bacteria isolated were Gram positive (61.3 and 52.3%), and Gram negative constituted only 38.7 and 47.7%. Out of the 214 PSB from a pool of 506 bacterial isolates recovered on the selective media from the rhizosphere of tea, 74 of them were characterized by carbon sources using BIOLOG M GN2 and GP2 plates. Bacillus, Pseudomonas, Paenibacillus and Stenotrophomonas genera were the most prominent P-solubilizing groups in the rhizosphere and soil populations analyzed. B. cereus, P. fluorescens, S. maltophilia, B. megaterium, P. putida, B. sphaericus and Paenibacillus polymyxa were the most frequent P-solubilizing species in the acidic tea rhizosohere soils. Selected Gram-positive PSB appeared to favour carbohydrates, and Gramnegative bacteria appeared to favour carboxylic acids, amino acids and carbohydrates as carbon sources. Selected phosphate solubilizing acid tolerant strains showed high variability in utilizing various carbon sources.

Diazotrophic bacilli isolated from the sunflower rhizosphere and the potential ofBacillus mycoidesB38V as biofertiliser

“…B. mycoides species grow on agar as chains of cells linked end‐to‐end, forming radial filaments curving clock‐ or counter‐clockwise (SIN or DX morphotypes) (Di Franco et al , ). Strains of B. mycoides have already been isolated from the rhizospheres of Elaeagnus angustifolia L. (Ramos et al , ), tea (Pandey & Palni, ; Çakmakçı et al , ), maize (Benizri et al , ) and native grapevine ( Vitis vinifera ) (Karagöz et al , ).…”

Diversity and Metabolic Potential of the Dominant Culturable N&lt;sub&gt;2&lt;/sub&gt;-Fixing and P-Solubilising Bacteria from Tea (&lt;i&gt;Camellia sinensis&lt;/i&gt; L.) Rhizosphere

“…Rhizosphere soil samples were collected carefully by uprooting the root system. Rhizospheric bacteria were isolated and identified according to the procedures described already [11]. Isolates were identified by fatty acid methyl ester (FAME) analysis using the Microbial Identification System (MIDI Inc., Newark, DE, USA).…”

“…Inorganic phosphate-solubilisation activity of the bacterial isolates was detected on Pikovskaya and NBRIP-BPB solid medium containing tricalcium-phosphate as sole source of P, as described earlier [11,13,14]. Soluble P in culture was then determined colorimetrically by the standard vanadomolybdophosphoric acid method.…”

“…Also, the effect of the tea plants on the rhizospheric bacteria has not been studied so far in this area. There is very little knowledge on the rhizosphere microbiology of the tea plants [9,11]. Currently, there is no information on the diversity and functional importance of N 2fixing (NFB) and P-solubilizing bacteria (PSB) in the acidic tea soils of southern coast of the Caspian Sea.…”

Endophytic and rhizospheric bacteria from Opuntia ficus-indica mill and their ability to promote plant growth in cowpea, Vigna unguiculata (L.) Walp

“…The analysis of the profile of cell wall fatty acids has been widely employed in studies on rhizospheric (Çakmakç et al, 2010;Misko and Germida, 2002) and endophytic microbial communities (Dias et al, 2009). This analysis was based in fact that some bacterial groups present unique lipidic profiles (Sasser, 1990).…”