scholarly journals Multi-Trait Wheat Rhizobacteria from Calcareous Soil with Biocontrol Activity Promote Plant Growth and Mitigate Salinity Stress

2021 ◽  
Vol 9 (8) ◽  
pp. 1588
Author(s):  
Anastasia Venieraki ◽  
Styliani N. Chorianopoulou ◽  
Panagiotis Katinakis ◽  
Dimitris L. Bouranis

Plant growth promoting rhizobacteria (PGPR) can be functional microbial fertilizers and/or biological control agents, contributing to an eco-spirit and safe solution for chemical replacement. Therefore, we have isolated rhizospheric arylsulfatase (ARS)-producing bacteria, belonging to Pseudomonas and Bacillus genus, from durum wheat crop grown on calcareous soil. These isolates harbouring plant growth promoting (PGP) traits were further evaluated in vitro for additional PGP traits, including indole compounds production and biocontrol activity against phytopathogens, limiting the group of multi-trait strains to eight. The selected bacterial strains were further evaluated for PGP attributes associated with biofilm formation, compatibility, salt tolerance ability and effect on plant growth. In vitro studies demonstrated that the multi-trait isolates, Bacillus (1.SG.7, 5.SG.3) and Pseudomonas (2.SG.20, 2.C.19) strains, enhanced the lateral roots abundance and shoots biomass, mitigated salinity stress, suggesting the utility of beneficial ARS-producing bacteria as potential microbial fertilizers. Furthermore, in vitro studies demonstrated that compatible combinations of multi-trait isolates, Bacillus sp. 1.SG.7 in a mixture coupled with 5.SG.3, and 2.C.19 with 5.SG.3 belonging to Bacillus and Pseudomonas, respectively, may enhance plant growth as compared to single inoculants.

2017 ◽  
Vol 9 (1) ◽  
pp. 167-172
Author(s):  
Sonal Bhardwaj ◽  
Bhawna Dipta ◽  
Shruti Kirti ◽  
Rajesh Kaushal

In the current study, a total of 25 isolates were isolated from the rhizosphere and roots of cauliflower (Brassica oleraceavar. botrytis L.) from the vicinity of Una district of Himachal Pradesh. The isolates were tested in vitro for their ability to solubilise phosphorous and produce siderophore, indole acetic acid (IAA), hydrogen cyanide (HCN) and antifungal metabolites against the soil borne pathogens. Results revealed that out of 25, only 4 rhizospheric isolates (SB5, SB11, SB8 and SB10) have maximum plant growth promoting attributes. The isolates were identified as Bacillus sp. on the basis of Bergey’s manual of systematic bacteriology. The isolate SB11 recorded highest phosphate solubilizing efficiency in solid medium (109.09%) and in liquid medium (350μg/ml). Maximum production of IAA (51.96μg/ml), siderophore (91.41%) and HCN were also observed for the same isolate. Further-more, the isolate SB11 produced highest antifungal metabolite production against Rhizoctoniasolani(37.11%), Sclerotiniasclerotiorum(41.11%), and Pythium sp. (71.11%) causing root rot, stalk rot and damping off diseases in cauliflower, respectively. The selected isolate (SB11) showed optimum growth at a pH of 7.0, 35°C temperature and 2% NaCl. On the basis of multifarious PGP-traits the SB11 isolate has tremendous potential to be used as a bioferti-lizer/bioprotectant for growth promotion and natural protection of cauliflower under low hill conditions of Himachal Pradesh.


2021 ◽  
Vol 15 (1) ◽  
pp. 428-436
Author(s):  
Devendra Jain ◽  
Gunnjeet Kaur ◽  
Ali Asger Bhojiya ◽  
Surya Chauhan ◽  
S.K. Khandelwal ◽  
...  

The present research was conducted to characterize the indigenous plant growth promoting (PGP) Azotobacter strains isolated from plant root interface of semi-arid regions of Rajasthan (India) and to study their potential to be used as bio-fertilizers. A total of 172 Azotobacter strains were isolated, purified and based on the morphological test i.e. gram staining, pigmentation, cyst formation, fluorescence etc, broadly classified as Azotobacter. Further the secluded strains were examined for biochemical analysis and plant growth promoting characters. All the isolates showed different biochemical characteristics and significant PGP traits. IAA activity of the Azotobacter strains ranges from 54.5-6000 µg/mL. Ammonia, HCN and siderophore was produced by 92.4%, 78.4% and 80.23% of the total isolates respectively. Solubilization of phosphate was observed in 97.6% of the total isolates. These strains were also characterized for qualitative and quantitative N2 fixation abilities and the result indicated that 114 strains showed positive results on nitrogen free malate agar medium (NFMM) containing bromothymol blue (BTB) and able to produce 18.93-475.6 N-moles C2H4 mg protein−1 h−1 of acetylene reduced by Azotobacter strains. In vitro pot studies revealed that the selected native Azotobacter strains having high ARA results significantly increase the plant growth characters. Shoot length, root length, root number and chlorophyll content and leaf number increases by 45.62%, 17.60%, 97.49%, 49.69% and 27.83% respectively in pot inoculated with AZO23-3 as compared to control. These effective strains can further be utilized for development of effective microbial formulations.


2020 ◽  
Author(s):  
Lubna Lubna ◽  
Muhammad Aaqil Khan ◽  
Sajjad Asaf ◽  
Rehmatullah Jan ◽  
Muhammad Waqas ◽  
...  

Abstract Background Salinity stress is one of the most devastating environmental stress that inhibits plants growth and development. Many strategies including plant growth promoting fungi have been reported to mitigate salt stress. Results In this study, we adopted environmental friendly technique and screened different plant growth promoting fungi for different PGP traits and salinity stress. Among these isolate CSL1 were selected based on the basis of plant growth promoting characteristics producing IAA, GAs, organic acid and tolerance to NaCl stress. Furthermore, inoculation of fungal isolate CSL1 significantly increased shoot length (16%), root length (37%), shoot fresh and dry weight (19% and 25%), root fresh and dry weight (47 and 51%) and chlorophyll content (24%) under NaCl stress (200 mM). Endogenous ABA level (0.77 folds) were significantly decreased while SA contents (16%) were increase in CSL1 inoculated plants under NaCl stress. Similarly, higher level of antioxidants such as MDA (2 folds), SOA (29%), POD (8 folds) and PPO (3 folds) was observed in NaCl treated non-inoculated plants. ICP analysis showed an increase in Na+ (11 folds) and decrease in K+ content (15%). Furthermore, CSL-1 inoculation improved soybean adaptability against NaCl stress and a significant decrease in GmFDL19 expression (5 folds) GmNARK (4 folds) and GmSIN1 (3 folds) was observed. However, higher expression of GmAKT2 (15%) were observed in CSL-1 treated plants. Conclusion Fungal isolate CSL-1 have capability to mitigate salinity stress in soybean, increase plant growth and could be used as valuable ecofriendly microorganism resource, low cost based biotechnological approach for sustainable agriculture in salt affected areas.


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.


Author(s):  
Peguy Flora Djuidje Kouomou ◽  
Cécile Annie Ewane ◽  
Sylvain Lerat ◽  
Denis Omokolo Ndoumou ◽  
Carole Beaulieu ◽  
...  

The focus of this study was to isolate, evaluate and characterize cocoyam rhizospheric actinobacteria collected from Mount Cameroon for their potential antagonistic activities against Pythium myriotylum, the causative agent of cocoyam root rot disease, and/or their ability to promote plant growth. Actinobacteria were isolated from soil samples by using serial dilution method. Dual culture assay was used to screen the isolates against fungal phytopathogens including P. myriotylum. The selected isolates were characterized morphologically, physiologically, biochemically and genetically. Furthermore, these isolates were subjected to in vitro production of various plant growth promoting (PGP) traits. Among the 287 isolates distributed into 12 distinct groups, PFK4, PFBOT7 and PFEL2 had high antagonistic effects against P. myriotylum and they were regarded as promising candidates for further study of their biocontrol ability. The identification of actinobacterial isolates was done using universal PCR of partial 16S rRNA sequences combined with bioinformatics and phylogenetic procedures. The results revealed that all these isolates belong to the genus Streptomyces spp. The isolate PFK4 showed 99% similarity with Streptomyces albulus while PFBOT7 showed 99% similarity with Streptomyces albus and PFEL2 showed 98% similarity with Streptomyces gandoceansis based on their 16S rRNA gene sequences. In this study for the first time, we report S. gandocaensis strain for the biological control of Pythium myriotylum. The role of these isolates in Plant Growth Promotion (PGP) by in vitro production of PGP traits such as phosphate solubilisation, siderophore, indole-3-acetic acid (IAA), ACC deaminase and cell wall degrading enzymes production were also evaluated and showed as potential PGP agents. Concurrent production of PGP substances coupled with broad spectrum of antifungal and antibacterial activities of these three strains suggest their potential use as promising biocontrol and PGP tools for the development of an alternative control method for cocoyam cultivation.


2020 ◽  
Author(s):  
Diriba Temesgen Dagaga ◽  
Fassil Assefa Tuji

Abstract BackgroundSoybean [Glycine max (L) Merr.] is an annual leguminous crop serving as a source of food and feed, green manure, biodiesel and fiber It is nodulated by diverse slow growing and fast growing rhizobia belonging to the genus Bradyrhizobium and Sinorhizobium, respectively. In Ethiopia, it has been cultivated since 1950s with lower grain yield history. Yield improvement efforts have been more concentrated on agronomic studies, inoculation of exotic Bradyrhizobium japonicum including TAL379 and/or fertilizer application. The results have usually been unsatisfactory and inconsistent. This study was initiated to identify promising indigenous soybean rhizobial inoculant that can enhance yield of the crop in the country.Methods Native soybean rhizobia, designated GMR for Glycine max rhizobia, were trapped using soybean (cv. Ethio-Yugoslavia) from soils collected across agro-ecologies of Ethiopia. Indigenous soybean rhizobia were screened for in vitro tolerance against physico-chemical stresses, plant growth promoting (PGP) traits and symbiotic performances at greenhouse and field levels A reference B. japonicum (TAL379) was included in all experiments. A soybean plant growth promoting Achromobacter sp. was also included in field trials for co-inoculation. Quantitative data were assessed by analysis of variance (ANOVA) employing SAS computer software package version 9.3. Mean separations were undertaken using the Duncan’s Multiple Range Test at p≤0.05.Result GMR that produced acid and grew faster with larger colonies were identified as Sinorhizobium spp. and those which produced alkali and grew slowly with smaller colonies were identified as Bradyrhizobium spp though further genetic analysis should be performed for verification and identification of their genus and species, respectively. Two Sinorhizobium spp (GMR120C and GMR125B) profoundly nodulated different soybean cultivars under greenhouse conditions and significantly improved grain yield (p≤0.05; maximum 3.98 tons ha-1) compared to 2.41, 2.82 and 2.69 recorded as maximum grain yield (tons ha-1) for TAL379 inoculation, positive control and negative control, respectively in field trials. Higher yield was recorded when GMR125B was coinoculated with Achromobacter sp., but when GMR120C was inoculated singly. These GMR also showed efficient utilization of numerous substrates, some PGP traits and potential adaptation to various ecological stresses. Conclusion The two Sinorhizobium spp. (GMR120C and GMR125B) are promising soybean inoculants that can be used to enhance the productivity of the crop in the country.


Plants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 912
Author(s):  
Shuming Liu ◽  
Hongmei Liu ◽  
Rui Chen ◽  
Yong Ma ◽  
Bo Yang ◽  
...  

Miscanthus spp. are energy plants and excellent candidates for phytoremediation approaches of metal(loid)s-contaminated soils, especially when combined with plant growth-promoting bacteria. Forty-one bacterial strains were isolated from the rhizosphere soils and roots tissue of five dominant plants (Artemisia argyi Levl., Gladiolus gandavensis Vaniot Houtt, Boehmeria nivea L., Veronica didyma Tenore, and Miscanthus floridulus Lab.) colonizing a cadmium (Cd)-contaminated mining area (Huayuan, Hunan, China). We subsequently tested their plant growth-promoting (PGP) traits (e.g., production of indole-3-acetic acid, siderophore, and 1-aminocyclopropane-1-carboxylate deaminase) and Cd tolerance. Among bacteria, two strains, Klebsiella michiganensis TS8 and Lelliottia jeotgali MR2, presented higher Cd tolerance and showed the best results regarding in vitro growth-promoting traits. In the subsequent pot experiments using soil spiked with 10 mg Cd·kg−1, we investigated the effects of TS8 and MR2 strains on soil Cd phytoremediation when combined with M. floridulus (Lab.). After sixty days of planting M. floridulus (Lab.), we found that TS8 increased plant height by 39.9%, dry weight of leaves by 99.1%, and the total Cd in the rhizosphere soil was reduced by 49.2%. Although MR2 had no significant effects on the efficiency of phytoremediation, it significantly enhanced the Cd translocation from the root to the aboveground tissues (translocation factor > 1). The combination of K. michiganensis TS8 and M. floridulus (Lab.) may be an effective method to remediate Cd-contaminated soils, while the inoculation of L. jeotgali MR2 may be used to enhance the phytoextraction potential of M. floridulus.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Sujit Shah ◽  
Krishna Chand ◽  
Bhagwan Rekadwad ◽  
Yogesh S. Shouche ◽  
Jyotsna Sharma ◽  
...  

Abstract Background A plant growth-promoting endophytic bacterium PVL1 isolated from the leaf of Vanda cristata has the ability to colonize with roots of plants and protect the plant. PVL1 was isolated using laboratory synthetic media. 16S rRNA gene sequencing method has been employed for identification before and after root colonization ability. Results Original isolated and remunerated strain from colonized roots were identified as Bacillus spp. as per EzBiocloud database. The presence of bacteria in the root section of the plantlet was confirmed through Epifluorescence microscopy of colonized roots. The in-vitro plantlet colonized by PVL1 as well as DLMB attained higher growth than the control. PVL1 capable of producing plant beneficial phytohormone under in vitro cultivation. HPLC and GC-MS analysis suggest that colonized plants contain Indole Acetic Acid (IAA). The methanol extract of Bacillus spp., contains 0.015 μg in 1 μl concentration of IAA. PVL1 has the ability to produce antimicrobial compounds such as ethyl iso-allocholate, which exhibits immune restoring property. One-way ANOVA shows that results were statistically significant at P ≤ 0.05 level. Conclusions Hence, it has been concluded that Bacillus spp. PVL1 can promote plant growth through secretion of IAA during root colonization and ethyl iso-allocholate to protect plants from foreign infections. Thus, this study supports to support Koch’s postulates of bacteria establishment.


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