scholarly journals Epiphytic and endophytic bacteria that promote growth of ethnomedicinal plants in the subtropical forests of Meghalaya, India

2014 ◽  
Vol 62 (4) ◽  
pp. 1295 ◽  
Author(s):  
Fenella Mary War Nongkhla ◽  
S. R. Joshi

<p>The present study was aimed to investigate the endophytic and epiphytic bacteria associated with selected ethnomedicinal plants from the pristine subtropical forests of Meghalaya and analyse them for plant growth promotion and antagonistic ability. This study is an attempt to explore plant associated bacteria which are beneficial to host plants, and thus aid in the conservation of ethnomedicinal plants of the studied subtropical forests, which are dwindling due to exploitation. The plant growth promotion parameters like indole acetic acid (IAA) production, mineral phosphate solubilisation, acid phosphatase activity, presence of 1-aminocyclopropane-1-carboxylic acid deaminase (ACC) gene, nitrogen fixation, cellulose digestion, chitin and pectin were screened among the isolates. The study revealed significant differences in bacterial population not only between the epiphytic and endophytic microhabitats, but also amongst the host plants. Out of the 70 isolated plant associated bacteria, <em>Bacillus </em>sp<em>., Serratia </em>sp<em>., </em><em>Pseudomonas </em>sp<em>.</em><em>, Pantoea </em>sp., and <em>Lysinibacillus</em> sp. showed potent plant growth promotion properties<em>. Bacillus siamensis </em>C53 and <em>B. subtilis </em>cenB showed significant antagonistic activity against the tested pathogens. This study indicated the isolates inhabiting the plants prevalent in the subtropical sacred forests that could be explored for use as plant growth promoters while practising the cultivation and conservation of ethnomedicinal plants.</p>

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Geetha Rajendran ◽  
Maheshwari H. Patel ◽  
Sanket J. Joshi

One of the ways to increase the competitive survivability of rhizobial biofertilizers and thus achieve better plant growth under such conditions is by modifying the rhizospheric environment or community by addition of nonrhizobial nodule-associated bacteria (NAB) that cause better nodulation and plant growth when coinoculated with rhizobia. A study was performed to investigate the most commonly associated nodule-associated bacteria and the rhizospheric microorganisms associated with theFenugreek(Trigonella foenum-graecum) plant. Isolation of nonrhizobial isolates from root nodules ofFenugreekwas carried out along with the rhizospheric isolates. About 64.7% isolates obtained fromFenugreeknodules were gram-negative coccobacilli, 29.41% were gram-positive bacilli, and all rhizospheric isolates except one were gram-positive bacilli. All the isolates were characterized for their plant growth promoting (PGP) activities. Two of the NAB isolates M2N2c and B1N2b (Exiguobacterium sp.) showed maximum positive PGP features. Those NAB isolates when coinoculated with rhizobial strain—S. meliloti, showed plant growth promotion with respect to increase in plant’s root and shoot length, chlorophyll content, nodulation efficiency, and nodule dry weight.


2020 ◽  
Vol 8 (4) ◽  
pp. 499 ◽  
Author(s):  
Ricardo Soares ◽  
Jesús Trejo ◽  
Maria J. Lorite ◽  
Etelvina Figueira ◽  
Juan Sanjuán ◽  
...  

Lotus spp. are widely used as a forage to improve pastures, and inoculation with elite rhizobial strains is a common practice in many countries. However, only a few Lotus species have been studied in the context of plant-rhizobia interactions. In this study, forty highly diverse bacterial strains were isolated from root nodules of wild Lotus parviflorus plants growing in two field locations in Portugal. However, only 10% of these isolates could nodulate one or more legume hosts tested, whereas 90% were thought to be opportunistic nodule associated bacteria. Phylogenetic studies place the nodulating isolates within the Bradyrhizobium genus, which is closely related to B. canariense and other Bradyrhizobium sp. strains isolated from genistoid legumes and Ornithopus spp. Symbiotic nodC and nifH gene phylogenies were fully consistent with the taxonomic assignment and host range. The non-nodulating bacteria isolated were alpha- (Rhizobium/Agrobacterium), beta- (Massilia) and gamma-proteobacteria (Pseudomonas, Lysobacter, Luteibacter, Stenotrophomonas and Rahnella), as well as some bacteroidetes from genera Sphingobacterium and Mucilaginibacter. Some of these nodule-associated bacteria expressed plant growth promotion (PGP) traits, such as production of lytic enzymes, antagonistic activity against phytopathogens, phosphate solubilization, or siderophore production. This argues for a potential beneficial role of these L. parviflorus nodule-associated bacteria.


Agronomy ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1850
Author(s):  
Mohamad Syazwan Ngalimat ◽  
Erneeza Mohd Hata ◽  
Dzarifah Zulperi ◽  
Siti Izera Ismail ◽  
Mohd Razi Ismail ◽  
...  

The usage of plant growth-promoting (PGP) Streptomyces to improve plant growth is an alternative to existing strategies of chemical fertilizers that commonly caused environmental pollution. The aim of this study was to isolate and characterize PGP Streptomyces from Malaysian rice fields with antagonistic activity against Bacterial Panicle Blight disease in rice caused by Burkholderia glumae. A total of 50 bacterial isolates were recovered from the soil, rhizosphere, and endosphere; 22% showed antagonistic activity against B. glumae. Molecular identification using 16S rRNA amplification and phylogenetic tree analyses revealed that the antagonistic isolates belonged to the genus Streptomyces. Among the antagonistic isolates, Streptomyces sp. TBS5 (26.35 ± 0.14 mm) demonstrated the most antagonistic activity (p < 0.05) against B. glumae. Through API® ZYM analysis, the antagonistic isolates were revealed to have phosphoric hydrolase, ester hydrolase, peptide hydrolase, and glycosidase activities that play a crucial role in plant growth promotion. The antagonistic isolates demonstrated the highest (80%) PGP traits including able to fix nitrogen and solubilize phosphate, as well as produce siderophore and indole-3-acetic acid. Plant growth promotion assay under laboratory and greenhouse conditions were analyzed with the treatment of rice, Oryza sativa, seeds with the antagonistic isolates. Seeds treated with Streptomyces sp. TBS5, JAS2, R2-7, and TKR8 showed improvement in vigor index by more than 100% compared to water-treated control plants under both conditions. Augmentation of root length showed an overall increment of more than 101.5% under laboratory condition and 151.9% under greenhouse condition using Streptomyces sp. TBS5, JAS2, R2-7, and TKR8 treatments. Results suggest that Streptomyces sp. TBS5, JAS2, R2-7, and TKR8 are a good candidate to be developed as both biocontrol agent against B. glumae and PGP agent in rice.


2014 ◽  
Vol 169 (9-10) ◽  
pp. 768-779 ◽  
Author(s):  
Nádia Castanheira ◽  
Ana Catarina Dourado ◽  
Paula Isabel Alves ◽  
Alícia Maria Cortés-Pallero ◽  
Ana Isabel Delgado-Rodríguez ◽  
...  

Biology ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 101
Author(s):  
Udaya Kumar Vandana ◽  
Jina Rajkumari ◽  
L. Paikhomba Singha ◽  
Lakkakula Satish ◽  
Hemasundar Alavilli ◽  
...  

The plant root is the primary site of interaction between plants and associated microorganisms and constitutes the main components of plant microbiomes that impact crop production. The endophytic bacteria in the root zone have an important role in plant growth promotion. Diverse microbial communities inhabit plant root tissues, and they directly or indirectly promote plant growth by inhibiting the growth of plant pathogens, producing various secondary metabolites. Mechanisms of plant growth promotion and response of root endophytic microorganisms for their survival and colonization in the host plants are the result of complex plant-microbe interactions. Endophytic microorganisms also assist the host to sustain different biotic and abiotic stresses. Better insights are emerging for the endophyte, such as host plant interactions due to advancements in ‘omic’ technologies, which facilitate the exploration of genes that are responsible for plant tissue colonization. Consequently, this is informative to envisage putative functions and metabolic processes crucial for endophytic adaptations. Detection of cell signaling molecules between host plants and identification of compounds synthesized by root endophytes are effective means for their utilization in the agriculture sector as biofertilizers. In addition, it is interesting that the endophytic microorganism colonization impacts the relative abundance of indigenous microbial communities and suppresses the deleterious microorganisms in plant tissues. Natural products released by endophytes act as biocontrol agents and inhibit pathogen growth. The symbiosis of endophytic bacteria and arbuscular mycorrhizal fungi (AMF) affects plant symbiotic signaling pathways and root colonization patterns and phytohormone synthesis. In this review, the potential of the root endophytic community, colonization, and role in the improvement of plant growth has been explained in the light of intricate plant-microbe interactions.


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