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

Abstract

The purpose of this study was to investigate the diversity of cultivable N 2 -fixing and P-solubilizing bacteria originated from 167 rhizospheric acidic soils samples of tea. Based on the fatty acid methyl ester profiles, 34 bacterial genera were identified with a similarity index of >0.3, but 69.2% of the identified isolates belonged to five genera: Bacillus, Pseudomonas, Paenibacillus, Stenotrophomonas and Arthrobacter. Among the 263 bacterial strains, 213 strains exhibited N 2fixing activity and 159 were efficient in phosphate solubilisation; 134 strains were efficient in N 2 -fixation and P-solubilisation. Most of the N 2 -fixing and P-solubilizing bacteria isolated were Gram-positive (59.3 and 52.8%), and Gram-negative constituted only 40.7 and 47.2%. A total of 102 dominant strains were characterized by carbon sources using BIOLOG M GN2 and GP2 plates. B. pumilus, B. subtilis, B. licheniformis, B. laevolacticus, P. fluorescens, P. putida, S. maltophilia and B. megaterium were the most frequent P-solubilizing and N 2 -fixing species in the tea rhizosphere soils. Utilization of high variety of C-sources by the N 2 -fixing and P-solubilizing acid tolerant strains may play an important role in adapting to a variety of crop plants, and thus potentially beneficial to the growth of tea plants in that specific acidic ecosystem.

The Variability of the Predominant Culturable Plant Growth-Promoting Rhizobacterial Diversity in the Acidic Tea Rhizosphere Soils in the Eastern Black Sea Region

“…The 556 Gram-positive isolates included 403 Firmicutes and 79 Actinobacteria. The data obtained show a greater abundance of Gram-positive bacteria in the tea rhizosphere, in agreement with previous studies (Xue et al, 2008;Rau et al 2009;Çakmakçı et al, 2010Çakmakçı et al, , Karagöz et al, 2012Varmazyari and Çakmakçı 2018) that show a higher level of Gram-positive Bacillus and Paenibacillus species in the in the tea garden soils. Also the tea rhizoplane was dominated by Bacillus (37% or 298/805 identified isolates).…”

“…The results obtained indicated that Bacillus, Pseudomonas, Paenibacillus, Stenotrophomonas, Brevibacillus and Arthrobacter genera were the most prominent culturable groups in the rhizosphere and soil populations. Bacteria from these genera are generally regarded as good phosphate solubilisers, nitrogen fixers and plant growth promoters (Xie et al, 2003;Şahin et al, 2004;Çakmakçı et al, 2006Chen et al 2006;Poonguzhali et al 2006;Beneduzi et al 2008;Hariprasad and Niranjana 2009;Rau et al 2009;Varmazyari and Çakmakçı 2018). B. cereus was the most dominant culturable NFB and PSB in the acidic tea rhizosphere, followed by P. fluorescens, B. megaterium, S. maltophilia, P. putida, B. licheniformis, B. pumilus, B. subtilis and P. polymyxa.…”

“…Selection of an efficient PGPR requires an understanding of the composition and diversity of the rootassociated bacteria, and characterization of its plant growth promotion-related properties. For this reason, there has been considerable interest in examining the effect of soil type, plant species and root zone location on bacterial community structure in the rhizosphere (Varmazyari and Çakmakçı, 2018). Furthermore, a good selection of PGPR strain requires an understanding the dynamic and composition of the bacterial communities colonizing the rhizosphere and characterization of its PGP related properties (Donate-Correa et al 2004;Çakmakçı et al, 2010).…”

Sustainable Applications of Endophytic Bacteria and Their Physiological/Biochemical Roles on Medicinal and Herbal Plants: Review

“…The phytochemical screening of green tea showed the presence of alkaloids, saponins, tannins, catechin, and polyphenols [ 56 , 141 ], which are quality parameters of tea. A study was conducted to examine the diversity of cultivable P-solubilizing bacteria in C. sinensis [ 142 ]. Over 900 rhizoplane bacteria were randomly selected and were identified using fatty acid methyl ester (FAME) analysis and isolates belonging to Bacillus (34.6%), Pseudomonas (8.9%), Stenotrophomonas (6.1%), Paenibacillus (5.9%), and Arthrobacter (4.8%) were identified [ 2 ].…”

A Review on Rhizosphere Microbiota of Tea Plant (Camellia sinensis L): Recent Insights and Future Perspectives

“…Of note, these two mechanisms (solubilization and mineralization) can coexist within the same PBKs . Apart from that, nonsymbiotic N-fixer Azotobacter also can solubilize the phosphate rocks . A critical survey of the available literature showed that most of the research outcomes of phosphate solubilizing microorganisms (PSMs) were focused on common crops, while little is known about tea cultivation’s role and future applicability.…”