scholarly journals Cultivable Endophytic Bacteria in Seeds of Dongxiang Wild Rice and Their Role in Plant-Growth Promotion

Diversity ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 665
Author(s):  
Zhibin Zhang ◽  
Tingting Liu ◽  
Xiao Zhang ◽  
Jing Xie ◽  
Ya Wang ◽  
...  

Dongxiang wild rice (Oryza rufipogon Griff.) germplasm is a precious resource for the improvement of agronomic traits in rice. Rice seeds also harbor a diverse endophytic bacterial community, and their interactions with their hosts and each other can influence plant growth and adaptability. Here, we investigated the community composition of cultivable endophytic bacteria obtained from the surface-sterilized seeds of Dongxiang wild rice and screened them for plant growth-promoting traits. Phylogenetic analysis of 16S rRNA gene sequences indicated that the 47 isolates were affiliated with five classes and 13 discrete genera, and Bacillus and Microbacterium predominated. Evaluations of plant growth promoting (PGP) traits showed that 45 endophytic bacteria isolates produced between 3.37 and 90.11 μg mL−1 of Indole-3-acetic acid (IAA), with the highest yield of 90.11 μg mL−1 (Fse28). Further, 37 of the isolates were able to solubilize mineral phosphate, while 28 other isolates had the ability of N2-fixation, 17 isolates possessed 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity with the highest yield of 20.72 μmol mg−1 protein h−1 (Fse35), and 17 isolates were also able to produce siderophores. The two strains Fse28 and Fse35 had multiple PGP traits that significantly improved the agronomic traits (root length, shoot length, dry matter, and chlorophyll content) of cultivated rice seedlings. Our results illustrate the rich diversity of seed endophytic bacteria in Dongxiang wild rice and their potential for developing novel efficient bioinoculants to enhance soil fertility and favor seedling growth.

2011 ◽  
Vol 108 ◽  
pp. 167-175 ◽  
Author(s):  
Qing Gui Zeng ◽  
Fei Luo ◽  
Zhi Bin Zhang ◽  
Ri Ming Yan ◽  
Du Zhu

The capability of bacterial strain T21 isolated from Dongxiang wild rice (Oryza rufipogon) rhizosphere to behave as plant growth promoting bacteria (PGPB) was investigated. Rhizosphere bacteria T21 showed P-solubilizing capability when cultured in the PVK medium amended with tricalcium phosphate. The strain T21 also showed nitrogen-fixing activity in N-free medium, and produced indole-3-acetic (IAA) and siderophore. The strain T21 was identified as Pantoea agglomerans by morphology, physiological and biochemical properties, and 16S rDNA sequence analysis. The strain T21 was formulated as an inoculant in order to evaluate its growth promotion effect in the field when applied on the cultivated rice at the sowing time. It showed a significant plant growth-promoting effect on seedling length, root length, fresh weight and dry weight of the cultivated rice (Oryza sativa). These findings fetched us to conclude that wild rice rhizospheric microorganism Pantoea agglomerans T21 could stimulate the growth of cultivated rice in vivo in poor soil.


Author(s):  
R. Thamizh Vendan ◽  
D. Balachandar

Background: Symbiotic associations between legumes and Rhizobia are ancient and fundamental. However, the plant growth-promoting endophytes other than Rhizobia are not yet fully explored for pulses productivity. The present study was aimed to isolate efficient endophytic bacteria from pulses, assess their diversity, screen their plant growth-promoting activities and to test their potential as bio inoculants for pulses.Methods: We have isolated several endophytic bacteria from pulse crops more specifically from blackgram (Vigna mungo) and greengram (Vigna radiata). After careful screening, 15 promising endophytic isolates were selected for this study. The identification of endophytic bacterial isolates was performed by 16S rRNA gene sequencing. The isolates were tested for their potential for the plant growth-promoting traits such as nitrogen fixation, phosphate solubilization, indole-3-acetic acid production, siderophore secretion and antifungal activity. Pot culture experiments were conducted with the screened potential endophytic cultures.Result: The 16S rRNA gene sequencing revealed that species of Enterobacter, Bacillus, Pantoea, Pseudomonas, Acromobacter, Ocrobacterium were found as endophytes in blackgram and greengram. The in vitro screening identified Bacillus pumilus (BG-E6), Pseudomonas fluorescens (BG-E5) and Bacillus licheniformis (BG-E3) from blackgram and Pseudomonas chlororaphis (GG-E2) and Bacillus thuringiensis (GG-E7) from greengram as potential plant growth-promoting endophytes. These strains showed antagonism against plant pathogenic fungi. Upon inoculation of these endophytic PGPR strains, the blackgram and greengram growth and yield got increased. Among the strains, BG-E6 recorded 14.7% increased yield in blackgram and GG-E2 accounted for a 19.5% yield increase in greengram compared to respective uninoculated control. The experimental results showed that there was a host specificity found among the endophytic bacterial cultures with pulses. The cross inoculation of endophytic strains did not perform well to enhance the growth and yield of their alternate hosts. 


Plants ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 1987
Author(s):  
Fahad Alotaibi ◽  
Soon-Jae Lee ◽  
Marc St-Arnaud ◽  
Mohamed Hijri

Phytoremediation, a method of phytomanagement using the plant holobiont to clean up polluted soils, is particularly effective for degrading organic pollutants. However, the respective contributions of host plants and their associated microbiota within the holobiont to the efficiency of phytoremediation is poorly understood. The identification of plant-associated bacteria capable of efficiently utilizing these compounds as a carbon source while stimulating plant-growth is a keystone for phytomanagement engineering. In this study, we sampled the rhizosphere and the surrounding bulk soil of Salixpurpurea and Eleocharis obusta from the site of a former petrochemical plant in Varennes, QC, Canada. Our objectives were to: (i) isolate and identify indigenous bacteria inhabiting these biotopes; (ii) assess the ability of isolated bacteria to utilize alkanes and polycyclic aromatic hydrocarbons (PAHS) as the sole carbon source, and (iii) determine the plant growth-promoting (PGP) potential of the isolates using five key traits. A total of 438 morphologically different bacterial isolates were obtained, purified, preserved and identified through PCR and 16S rRNA gene sequencing. Identified isolates represent 62 genera. Approximately, 32% of bacterial isolates were able to utilize all five different hydrocarbons compounds. Additionally, 5% of tested isolates belonging to genera Pseudomonas, Acinetobacter, Serratia, Klebsiella, Microbacterium, Bacillus and Stenotrophomonas possessed all five of the tested PGP functional traits. This culture collection of diverse, petroleum-hydrocarbon degrading bacteria, with multiple PGP traits, represents a valuable resource for future use in environmental bio- and phyto-technology applications.


2021 ◽  
Author(s):  
Jia-Qi Liu ◽  
Chun-Mei Zhang ◽  
Yuan Gong ◽  
Ming-Jie Xu ◽  
Ke Xing ◽  
...  

Abstract Purpose Arctium lappa L. is one of the medicinal and food homologous plants in China, which is rich in nutrients and medicinal ingredients. The use of plant growth promoting (PGP) endophytic bacteria is a useful alternative in agricultural production to reduce the use of chemical fertilizers. The aim of this study was to analysis the diversity of endophytic bacteria in different cultivars of A. lappa L. collected from two different geographical locations in China and evaluate PGP traits of the isolates and their potential PGP ability in greenhouse condition. Methods Endophytic bacterial community was investigated by culture-dependent and culture-independent methods. Isolates were screened and investigated for multiple PGP traits, and representative strains were inoculated host seedlings to evaluate the growth promoting effect. Results A total of 348 endophytic bacteria were obtained and they distributed into four phyla, 30 genera and 73 different species. In addition, high throughput sequencing revealed more abundant bacterial community, including 17 bacterial phyla, and 207 different known genera. A high proportion of PGP traits were detected, including production of indole acetic acid, siderophore, ammonia and phosphate solubilization. Four representative strains with multiple PGP traits of the most prevalent genera were further selected for host inoculation and growth promoting evaluation, and they significantly increase seedlings length, root length and fresh weight. Conclusion This study demonstrated that A. lappa L. harbors abundant endophytic bacteria, and plant genotype and geographical origin affect their composition. Moreover, some endophytic bacteria showed good potential for the development of microbial fertilizer in the future.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Sangeeta Pandey ◽  
Shikha Gupta

Abstract1-Aminocyclopropane-1-carboxylate (ACC) deaminase activity is one of the most beneficial traits of plant growth promoting (PGP) rhizobacteria responsible for protecting the plants from detrimental effects of abiotic and biotic stress. The strain S3 with ACC deaminase activity (724.56 nmol α-ketobutyrate mg−1 protein hr−1) was isolated from rhizospheric soil of turmeric (Curcuma longa), a medicinal plant, growing in Motihari district of Indian state, Bihar. The halotolerant strain S3, exhibited optimum growth at 8% (w/v) NaCl. It also exhibited multiple PGP traits such as indole acetic acid production (37.71 μg mL−1), phosphate solubilization (69.68 mg L−1), siderophore, hydrocyanic acid (HCN) and ammonia production as well as revealed antagonism against Rhizoctonia solani. The potential of isolated strain to alleviate salinity stress in tomato plants was investigated through pots trials by inoculating strain S3 through-seed bacterization, soil drenching, root dipping as well as seed treatment + soil drenching. The strain S3 inoculated through seed treatment and soil drenching method led to improved morphological attributes (root/shoot length, root/shoot fresh weight and root/shoot dry weight), photosynthetic pigment content, increased accumulation of osmolytes (proline and total soluble sugar), enhanced activities of antioxidants (Catalase and Peroxidase) and phenolic content in salt stressed tomato plants. The biochemical characterisation, FAMEs analysis and 16S rRNA gene sequencing revealed that strain S3 belongs to the genus Pseudomonas. The overall findings of the study revealed that Pseudomonas sp. strain S3 can be explored as an effective plant growth promoter which stimulate growth and improve resilience in tomato plants under saline condition.


Plants ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 42 ◽  
Author(s):  
Clarisse Brígido ◽  
Sakshi Singh ◽  
Esther Menéndez ◽  
Maria Tavares ◽  
Bernard Glick ◽  
...  

The aims of this study were to isolate, identify and characterize culturable endophytic bacteria from chickpea (Cicer arietinum L.) roots grown in different soils. In addition, the effects of rhizobial inoculation, soil and stress on the functionality of those culturable endophytic bacterial communities were also investigated. Phylogenetic analysis based on partial 16S rRNA gene sequences revealed that the endophytic bacteria isolated in this work belong to the phyla Proteobacteria, Firmicutes and Actinobacteria, with Enterobacter and Pseudomonas being the most frequently observed genera. Production of indoleacetic acid and ammonia were the most widespread plant growth-promoting features, while antifungal activity was relatively rare among the isolates. Despite the fact that the majority of bacterial endophytes were salt- and Mn-tolerant, the isolates obtained from soil with Mn toxicity were generally more Mn-tolerant than those obtained from the same soil amended with dolomitic limestone. Several associations between an isolate’s genus and specific plant growth-promoting mechanisms were observed. The data suggest that soil strongly impacts the Mn tolerance of endophytic bacterial communities present in chickpea roots while rhizobial inoculation induces significant changes in terms of isolates’ plant growth-promoting abilities. In addition, this study also revealed chickpea-associated endophytic bacteria that could be exploited as sources with potential application in agriculture.


Author(s):  
Eder Gonçalves Queiroz ◽  
Juliana Degenhardt ◽  
Marguerite Quoirin ◽  
Krisle da Silva

Abstract: The objective of this work was to isolate endophytic bacteria from tissue culture and leaves of jaboticaba (Plinia peruviana) and to evaluate their potential as plant growth-promoting bacteria. The bacteria were isolated from nodal segments grown in vitro and from leaves from a tree under natural conditions, totaling 11 and 54 isolates, respectively. The isolates were characterized by colony morphology. The indolic compounds produced by the isolates, in the presence or absence of 100 mg L-1 tryptophan, were quantified. The greatest producers of these compounds were identified by sequencing the 16S rRNA gene and were inoculated on jaboticaba seeds, using Azospirillum brasilense (Ab-V6) as a positive control. The sensitivity of bacteria to eight antibiotics was also evaluated. All assessed bacteria produced indolic compounds, especially Bacillus sp., with a content of 27.41 μg mL-1. The germination rate of the seeds inoculated with Stenotrophomonas sp. was high - 97.34% compared with that of 74.67% of the negative control. Bacillus sp. and Stenotrophomonas sp. also sped up germination. Chloramphenicol limited the growth of 82% of the isolates, followed by amoxicillin, gentamicin, levofloxacin, and tetracycline, which limited 70%; erythromycin was only effective against 35%. The endophytic bacteria isolated from jaboticaba show characteristics of plant growth-promoting bacteria, and Bacillus sp. and Stenotrophomonas sp., obtained from tissue culture, are capable of enhancing jaboticaba seed germination.


2016 ◽  
Vol 68 (2) ◽  
pp. 363-374 ◽  
Author(s):  
Pankaj Kumar ◽  
Ramesh Dubey ◽  
Dinesh Maheshwari ◽  
Yong-Ha Park ◽  
Vivek Bajpai

In vitro screening of plant growth-promoting (PGP) traits was carried out using eight Pseudomonas spp., PPR1 to PPR8, isolated from the rhizosphere of Phaseolus vulgaris growing on the Uttarakhand Himalayan range in India. All the isolates were fast growers, positive for catalase, oxidase and urease activities, and utilized lactose and some amino acids. All the isolates were indole acetic acid (IAA) positive, however PPR8 solubilized potassium and zinc along with various other types of inorganic (tricalcium, dicalcium and zinc phosphate) and organic (calcium phytate) phosphates, as well as producing siderophore and ACC deaminase. PPR8 also produced cyanogens, extracellular chitinase, ?-1,3-glucanase, ?-1,4-glucanase and oxalate oxidase. Based on the PGP traits of all isolates, PPR8 was found to be the most potent plant growth-promoting rhizobacteria (PGPR). Further, PPR8 was identified as Pseudomonas sp. PPR8, based on 16S rRNA gene sequencing analysis. Moreover, the PGP activities of PPR8 confirmed it to be a potent biocontrol agent, inhibiting the growth of various plant pathogenic fungi. This study reveals the potential of Pseudomonas sp. PPR8 to be used as a good bioinoculant for growth promotion of common bean and for the protection of important legume crops from various deleterious phytopathogens.


2021 ◽  
Author(s):  
Frederico Leitão ◽  
Glória Pinto ◽  
Joana Amaral ◽  
Pedro Monteiro ◽  
Isabel Henriques

Abstract The rhizobiome is being increasingly acknowledged as a key player in plant health and breeding strategies. The pine pitch canker (PPC), caused by the fungus Fusarium circinatum, affects pine species with varying susceptibility degrees. Our aims were to explore the bacterial rhizobiome of a susceptible (Pinus radiata) and a resistant (Pinus pinea) species together with other physiological traits, and to analyze shifts upon F. circinatum inoculation. Pinus seedlings were stem inoculated with F. circinatum spores and needle gas exchange and antioxidant-related parameters were analyzed in non-inoculated and inoculated plants. Rhizobiome structure was evaluated through 16S rRNA gene massive parallel sequencing. Species (non-inoculated plants) harbored distinct rhizobiomes (<40% similarity), where P. pinea displayed a rhizobiome with increased abundance of taxa described in suppressive soils, displaying plant-growth-promoting (PGP) traits and/or antifungal activity. Plants of this species also displayed higher levels of phenolic compounds. Fusarium circinatum induced slight changes in the rhizobiome of both species and a negative impact in photosynthetic-related parameters in P. radiata. We concluded that the rhizobiome of each pine species is distinct and higher abundance of bacterial taxa associated to disease protection was registered for the PPC-resistant species. Furthermore, differences in the rhizobiome are paralleled by a distinct content in phenolic compounds, which are also linked to plants’ resistance against PPC. This study unveils a species-specific rhizobiome and provides insights to exploit the rhizobiome for plant selection in nurseries and for rhizobiome-based plant-growth-promoting strategies, boosting environmentally friendly disease control strategies.


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