scholarly journals Enhanced growth of cabbage seedlings by a Paenibacillus isolate in the presence of Xanthomonas campestris pv campestris

2015 ◽  
Vol 68 ◽  
pp. 173-178
Author(s):  
H. Ghazalibiglar ◽  
J.G. Hampton ◽  
E. van_Zijll De_Jong ◽  
A. Holyoake

Paenibacillus spp are rhizobacteria that can promote plant growth through a range of mechanisms A New Zealand isolate of Paenibacillus P16 has reduced the incidence of black rot caused by Xanthamonas campestris pv campestris (Xcc) in brassicas To investigate if this response was provided through plant growth promotion isolate P16 was coapplied with Xcc as a seed treatment In the presence of Xcc P16treated seedlings had significantly greater root length leaf area and root and shoot dry weight compared to the positive control (Xcc alone) There were no significant differences in plant growth parameters between P16treated seedlings in the absence of the pathogen and the negative control (seeds without Xcc or P16) Isolate P16 enabled plants to survive and grow normally by preventing disease development; the mechanism of disease suppression requires further investigation

Author(s):  
Mahmoud Ahmed Touny El-Dabaa ◽  
Hassan Abd-El-Khair

Abstract Background Orobanche crenata is an obligate root parasite belonging to Orbanchaceae. Broomrape causes great damage to the faba bean. Several attempts were applied for controlling parasitic weeds. So, the aim of this work is to study the application of Trichoderma spp. as well as three rhizobacteria species in comparison to herbicidal effect of Glyphosate (Glialka 48% WSC) for controlling broomrape infesting faba bean (Vicia faba). Materials and methods Three pot experiments were carried out in the greenhouse of the National Research Centre, Dokki, Giza, Egypt during two successive winter seasons. Trichoderma inocula were adjusted to 3.6 × 108 propagules/ml and the bacterium inocula were adjusted at 107–109 colony-forming unit (CFU)/ml. All treatments were applied, before 1 week of sowing, at rate of 50 ml per pot in experiments I and II, while 100 ml per pot in experiment III. Results Trichoderma spp. (T. harzianum, T. viride and T. vierns) as well as three rhizobacteria species (Pseudomonas fluorescens, Bacillus subtilis and Bacillus pumilus) enhanced the growth parameters in faba bean plants, i.e. shoot length, shoot fresh weight, shoot dry weight and leaf number in the first experiment when applied without O. crenata infection. In the second experiment, all bio-control could protect plants against O. crenata infection, where it had better juvenile number reduction, than glyphosate after 2 months of application. Both B. subtilis and B. pumilus had the highest reduction to juvenile fresh weight, while their effect was equal to herbicide for juvenile dry weight, respectively. The bio-control agents had high effects until the 4th month, but it was less than that of the herbicide. In experiment III, the bio-control agents could highly reduce the juvenile parameters after 2 months, as well as juvenile fresh weight and juvenile dry weight after 4 months, than the herbicide, respectively. The bio-control agents were effective until 6 months, but less than the herbicide effect. All bio-control treatments highly increased the plant growth parameters, than the herbicide. Conclusion The application of Trichoderma spp. as well as rhizobacteria species could play an important role in controlling broomrape in faba bean as a natural bioherbicide.


mSphere ◽  
2020 ◽  
Vol 5 (4) ◽  
Author(s):  
Dario X. Ramirez-Villacis ◽  
Omri M. Finkel ◽  
Isai Salas-González ◽  
Connor R. Fitzpatrick ◽  
Jeffery L. Dangl ◽  
...  

ABSTRACT Glyphosate is a commonly used herbicide with a broad action spectrum. However, at sublethal doses, glyphosate can induce plant growth, a phenomenon known as hormesis. Most glyphosate hormesis studies have been performed under microbe-free or reduced-microbial-diversity conditions; only a few were performed in open systems or agricultural fields, which include a higher diversity of soil microorganisms. Here, we investigated how microbes affect the hormesis induced by low doses of glyphosate. To this end, we used Arabidopsis thaliana and a well-characterized synthetic bacterial community of 185 strains (SynCom) that mimics the root-associated microbiome of Arabidopsis. We found that a dose of 3.6 × 10−6 g acid equivalent/liter (low dose of glyphosate, or LDG) produced an ∼14% increase in the shoot dry weight (i.e., hormesis) of uninoculated plants. Unexpectedly, in plants inoculated with the SynCom, LDG reduced shoot dry weight by ∼17%. We found that LDG enriched two Firmicutes and two Burkholderia strains in the roots. These specific strains are known to act as root growth inhibitors (RGI) in monoassociation assays. We tested the link between RGI and shoot dry weight reduction in LDG by assembling a new synthetic community lacking RGI strains. Dropping RGI strains out of the community restored growth induction by LDG. Finally, we showed that individual RGI strains from a few specific phyla were sufficient to switch the response to LDG from growth promotion to growth inhibition. Our results indicate that glyphosate hormesis was completely dependent on the root microbiome composition, specifically on the presence of root growth inhibitor strains. IMPORTANCE Since the introduction of glyphosate-resistant crops, glyphosate has become the most common and widely used herbicide around the world. Due to its intensive use and ability to bind to soil particles, it can be found at low concentrations in the environment. The effect of these remnants of glyphosate in plants has not been broadly studied; however, glyphosate 1,000 to 100,000 times less concentrated than the recommended field dose promoted growth in several species in laboratory and greenhouse experiments. However, this effect is rarely observed in agricultural fields, where complex communities of microbes have a central role in the way plants respond to external cues. Our study reveals how root-associated bacteria modulate the responses of Arabidopsis to low doses of glyphosate, shifting between growth promotion and growth inhibition.


Biocelebes ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 1-9
Author(s):  
Wahyu Harso ◽  
Isna Isna ◽  
Yusran Yusran

Arbsucular mycorrhizal fungi promote plant growth by enhancing mineral uptake. Contribution degree of arbuscular mycorrhizal fungi to promote plant growth depend on species of plant-fungus association. The aim of this study was to compare the ability of three species of Glomus to promote maize plant growth. Maize plants were inoculated with 20 g inoculum of either Glomus deserticola, Glomus etunicatum, or Glomus clorum.  Inoculum was soil containing spore, hyphae and infected root. Maize plants without addition inoculum were also used as a control. Water availability in the soil as growing medium was maintained on 40% field capacity. The results showed that addition of inoculum from three species of Glomus increased average of maize plant shoot dry weight  although there was no statisticaly significant differences.  Maize plant inoculated with G. clorum had higher shoot dry weight than maize plant inoculated either with G. etunicatum or G. deserticola while root colonization by G. clorum was lowest.


2019 ◽  
Vol 67 (4) ◽  
Author(s):  
Felipe Romero-Perdomo ◽  
Jhonnatan Ocampo-Gallego ◽  
Mauricio Camelo-Rusinque ◽  
Ruth Bonila

In this study, we aimed at examining the potential to stimulate growth in Pennisetum clandestinum using four isolated bacterial strains from soils obtained from a Colombian tropical silvopastoral system. We previously identified genetically the strains and characterized two plant growth promotion activities. We found that the four bacterial strains were phylogenetically associated with Klebsiella sp. (strains 28P and 35P), Beijerinka sp. (37L) and Achromobacter xylosoxidans (E37), based on partial 16S rRNA gene sequencing. Moreover, the in vitro biochemical assays demonstrated that the strains exhibited some plant growth promotion mechanisms such as 1-aminocyclopropane-1-carboxylic acid deaminase activity and indole compound synthesis. Notably, bacterial inoculation under greenhouse conditions showed a positive influence on P. clandestinum growth. We found a significant (p < 0.05) effect on root and shoot length, and shoot dry weight. Shoot length increased by 52% and 30% with 37L and 35P, respectively, compared to those without inoculation treatment. Similarly, the use of 37L and 28P raised shoot dry weight values by 170% and 131%, respectively. In root development, inoculation with strains 37L and E37 increased root length by 134% and 100%, respectively. Beijerinckia sp. 37L was the most effective of the four strains at increasing P. clandestinum biomass and length.


Author(s):  
Zhao L ◽  
◽  
Zhao W ◽  
Deng H ◽  
◽  
...  

Some fungi may promote plant growth by production of siderophores, Indole Acetic Acid (IAA) and phosphorus dissolving capability. In this study, eight fungi were isolated from the mushroom substrate, and their siderophores production, IAA production and phosphorus dissolving traits were determined. Although there was no significant difference in IAA production among the eight fungi, but the strain M13026-2 was a fungus with strong growth promoting traits compared with other seven fungi. In order to study the correlation between the growth promoting effect of cucumber pot culture and the above three traits, five fungi with different strength of traits were tested in pot. As a result, M13026- 2 which was identified as Talaromyces purpureogenus could significantly improve the growth parameters of cucumber seedlings, and could colonize in the rhizosphere soil and the tissue of cucumber stably. All the results suggested that the most relevant to their ability to promote plant growth is the trait of phosphorus dissolving, followed by siderophores production. The results of this study will provide scientific basis for the efficient selection and identification of a large number of fungi resources with the function of promoting plant growth, and reveal the good application potential of T. purpureogenus in agriculture fields.


Author(s):  
Anju Sehrawat ◽  
Aakanksha Khandelwal ◽  
Satyavir Singh Sindhu

Mesorhizobium sp. indirectly promote the growth of plants as a biocontrol agent by inhibiting the growth of pathogens particularly Fusarium wilt of chickpea. Out of 24 Mesorhizobium isolates obtained from chickpea nodules, eight isolates showed antagonistic effect against Fusarium oxysporum. Salinity stress severely affects growth, nodulation and yield of chickpea. Mesorhizobium isolates were tested for their salt tolerance capacity at 1, 2, 4, 6 and 8% NaCl concentrations. Only two Mesorhizobium isolates MCA5 and MCA22 were found salt-tolerant upto 8% of salt concentration. Maximum increase (45.5%) in shoot dry weight was observed by inoculation of isolate MCA20 at 40 days of chickpea growth under chillum jar conditions, whereas isolate MCA23 resulted in 166.2% increase in root dry weight. Likewise, 112.6% increase in shoot dry weight was observed on inoculation of MCA14 isolate at 80th day of observation. Further extensive research is required to understand the mechanism of potential Mesorhizobium isolates of chickpea in controlling Fusarium wilt disease and salt tolerance. Selection of mesorhizobia with twin functional traits (plant growth promoting and biocontrol agent) can be exploited as future biofertilizer in chickpea.


2020 ◽  
Vol 38 ◽  
Author(s):  
S. BANARAS ◽  
A. JAVAID ◽  
A. SHOAIB

ABSTRACT: Urdbean [Vigna mungo (L.) Hepper] is an important leguminous crop whose production is severely affected by charcoal rot disease caused by Macrophomina phaseolina. This study was undertaken to seek an environmental friendly alternative to synthetic fungicides for management of this disease. Dry biomass of an allelopathic weed Sonchus oleraceous L. was used to combat the menace. Fumigated sandy loam pot soil, pre-inoculated with M. phaseolina, was amended with different doses of dry biomass of the weed ranging from 0.5% to 3%. Application of 2% weed biomass completely controlled the disease. Soil inoculation with M. phaseolina inoculation (positive control) reduced shoot dry weight and grain yield of urdbean by 59% and 91%, respectively, over negative control. Application of different doses of soil amendment in pathogen inoculated soil enhanced shoot dry weight and grain yield of urdbean by 107-307% and 438-7400%, respectively, over positive control. The highest positive effect on growth and yield of uedbean in M. phaseolina contaminated soil was recorded due to 2.5% amendment. M. phaseolina inoculation significantly enhanced peroxidase (POX) and phenyl alanine ammonia lyase (PAL) activities. However, application of different doses of S. oleraceous biomass to the soil gradually decreased activities of these enzymes. The present study concludes that application of 2.5% dry biomass of S. oleraceous can completely control charcoal rot of urdbean and significantly enhance crop growth and yield.


Bionatura ◽  
2019 ◽  
Vol 4 (1) ◽  
Author(s):  
Jorge A. Sierra-Escobar ◽  
John Alexander Ortíz-Correa

A greenhouse experiment was designed to determine the mycorrhizal symbiotic effectiveness in native mycorrhizal fungi population associated with different soil coverage in the Cesar department. The experimental design was completely randomized with nine treatments and six variations per treatment, 54 experimental units in all. Treatments consisted of combination of soils which contained a substrate from different mulches or soil coal mining (soil-coverage): natural forest (NF), transition soil (TS), a horizon (AH), mining waste (MW), palm (PM), pastures (PT), undisturbed soil (US), with its respective controls, positive Glomus mosseae (GM) and negative sterile substrate without inoculum (WI). The variables studied were foliar P content was monitored as a function of time; at harvest, shoot dry weight, shoot P content, and mycorrhizal colonization represented the time increments. The higher contents of P foliar obtained in the sampling period were for the positive control (GM) showing significant differences between soil-coverage, except for ST and US assessed on the sampling day 74. Shoot dry weight had a significant difference in GM, NF, TS, AH, PM and US treatments compared to the remaining three. Treatments with the most weight were US and GM (positive control). Mining waste (MW), PT and WI (negative control) had the lowest values in mass. As expected, shoot P content in the GM samples was higher and had significant differences compared to the other treatments. Soil-coverage closest to the positive control were NF, US, and TS. All assessed treatments showed mycorrhizal colonization except the negative control (WI). Three soil-coverages PM, PT, and US were similar to the positive control, with colonization percentages of 29, 24 and 48 respectively. In conclusion, this kind of research suggests that symbiotic effectiveness experiments are an excellent tool for the selection of native arbuscular mycorrhizal fungi. Besides, and as evidenced, soil-coverage NIT was statistically similar to the positive control (GM), which makes it a candidate for mass crude inoculum production for restoration purposes.


2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Enriqueta Amora-Lazcano ◽  
Héctor J. Quiroz-González ◽  
Cristofer I. Osornio-Ortega ◽  
Juan A. Cruz-Maya ◽  
Janet Jan-Roblero

Background: Deficiency in sorghum growth in ecosystems of low-nutrient soils has been scarcely studied. This soil deficiency can be overcome by the addition of plant growth-promoting bacteria which increase sorghum growth. Questions and/or Hypotheses: indole acetic acid (IAA) producing and phosphate solubilizing bacteria can promote sorghum growth under nutritional stress. Studied species: Sorghum bicolor (L.) Moench. Study site and dates: Mexico City, 2018. Methods: Of the twelve bacterial strains utilized, three produce IAA (group BI), two strains produce IAA and siderophores (BIS group), four strains produce IAA and solubilize phosphate (BIP group), and three strains produce IAA, solubilize phosphate, and produce siderophores (BIPS group). Hydroponic bioassays and low-nutrient soil bioassay were used. Results: In hydroponic bioassays, for BI and BIS groups, five strains significantly increased the growth parameters with respect to the control, and for the BIP and BIPS groups, two strains promoted stem development and shoot dry weight. In a low-nutrient soil bioassay, Pseudomonas sp. BI-1 (from BI group) was the one that presented the highest percentages 32, 48, 140 and 79 % in stem diameter, height and dry weight of the shoot and dry weight of the root, respectively, followed by the P. mohnii BIPS-10 strain (from BIPS group) that exhibited similar results. Conclusions: IAA producing Pseudomonas strains improve the sorghum growth in a low-nutrient soil and suggest thatPseudomonas sp. BI-1 and P. mohnii BIPS-10 could be used as potential bioinoculants for sorghum.


2019 ◽  
Vol 22 (02) ◽  
pp. 395-400
Author(s):  
Saqer Alotaibi

The reaction of four wheat RbcS RNAi mutants and wild type to the infection of M. incognita was investigated in a greenhouse pot experiment using plant growth parameters as well as nematode reproduction. Obtained results revealed that all estimated growth parameters of lines under study were reduced by M. incognita infection to various extents. RSS13.2 line showed the highest percentage of reduction of plant total fresh weight, length, and shoot dry weight. It did act as good host for root-knot nematode; therefore, it was classified as susceptible host. In addition, the lowest reduction percentage of fresh and dry weights was observed in RSS8.5 line although it showed high values for nematode development and reproduction parameters; therefore, it seemed to be as a tolerant host. The maximum reduction in chlorophyll content was recorded in RSS7.6 line, whereas, the minimum was obtained from RSS11.5 line. It was evident that none of the five tested wheat lines was immune to M. incognita infection. The lowest numbers of second stage juveniles, galls, and egg-masses were observed in soil and on roots of RSS11.5 line although its plant growth was slightly affected; therefore, it is considered as partially resistant line. It could be concluded from the results of this study that, RNAi mutants of the RbcS were partially effective in suppressing root-knot nematode development. © 2019 Friends Science Publishers


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