Tomato bacterial endophytes in controlling Verticillium wilt and their advantage on biostimulation

2021 ◽  
Vol 14 (1) ◽  
pp. 1-13
Author(s):  
N. Zendehdel ◽  
N. Hasanzadeh ◽  
F.B. Firouzjahi ◽  
S. Naeimi

SummaryA total of 688 bacterial endophytes were isolated from both greenhouse and field-grown tomatoes in the Tehran and Alborz provinces, Iran in order to obtain effective bacterial endophytes against the fungus Verticillium dahliae. 128 bacterial isolates, with respect to their different phenotypic characteristics were further analysed. All bacteria with positive hypersensitivity reaction on tobacco and geranium leaves and potato soft rot were eliminated, and totally 39 isolates were selected for in vitro antagonism and greenhouse tests. The potential biocontrol isolates were evaluated using seed treatment and soil drench methods on two tomato cultivars. The results indicated that seven bacterial isolates had a high potential for the control of the fungus and reduced the severity disease to 95-98%. This reduction was coincided with an increase in some growth factors like plant dry weight, root dry weight, plant height, root length, root fresh weight and plant fresh weight ranged between 92-98%. The seven antagonists’ preliminary identification was confirmed using 16SrRNA gene sequencing analysis. The BLAST analysis was performed, and the bacteria were also identified as Bacillus pumilus (two isolates), Bacillus subtilis, Bacillus safensis, Enterobacter ludwigi, Serratia marcesens and Pseudomonas beatica. Biocontrol mechanisms examination indicated that protease production was positive for all isolates and differentiated isolates E. ludwigii and P. beatica as higher producers with protease levels up to 65%. The three bacteriocins producing isolates inhibited the phytopathogenic mycelium up to 70% in dual culture assay. Also, five of the isolates produced siderophores and P. baetica, S. marcesens and E. ludwigii produced remarkable amount of auxin hormone.

2020 ◽  
Vol 14 (2) ◽  
pp. 178-186
Author(s):  
Lisa Novita Arios ◽  
Dwi Suryanto . ◽  
Kiki Nurtjahja . ◽  
Erman Munir .

Assay on ability of endophytic bacteria isolated from peanut to inhibit Sclerotium sp. growth in peanut seedlings.   A study on assay of ability of endophytic bacteria to inhibit Sclerotium sp. in peanut seedling has been done. The bacteria were isolated from peanut healthy plants, while Sclerotium sp. was isolated from infected peanaut plant. Antagonistic assay was conducted by dual culture method.  In vivo assay of inhibiting Sclerotium sp. was conducted by dipping peanut seed in bacterial solution, and planting the seed in soil:compost (3:1) growing media. Six endophytic bacterial isolates showed to inhibit the growth of Sclerotium sp. in vitro. LN1 seemed to inhibit more of Sclerotium sp., while LN5 showed to inhibit less. Two potential isolates LN1 of gram-negative and LN2 of gram-positive using for further study showed to decrease more of dumping off. It also seemed that the isolates increased the seedling height, number of leaves, and dry weight.


Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5340
Author(s):  
Alicja Tymoszuk

The interactions between nanoparticles and plant cells are still not sufficiently understood, and studies related to this subject are of scientific and practical importance. Silver nanoparticles (AgNPs) are one of the most commonly produced and used nanomaterials. This study aimed to investigate the influence of AgNPs applied at the concentrations of 0, 50, and 100 mg·L−1 during the process of in vitro germination as well as the biometric and biochemical parameters of developed seedlings in three vegetable species: Solanum lycopersicum L. ‘Poranek’, Raphanus sativus L. var. sativus ‘Ramona’, and Brassica oleracea var. sabellica ‘Nero di Toscana’. The application of AgNPs did not affect the germination efficiency; however, diverse results were reported for the growth and biochemical activity of the seedlings, depending on the species tested and the AgNPs concentration. Tomato seedlings treated with nanoparticles, particularly at 100 mg·L−1, had shorter shoots with lower fresh and dry weights and produced roots with lower fresh weight. Simultaneously, at the biochemical level, a decrease in the content of chlorophylls and carotenoids and an increase in the anthocyanins content and guaiacol peroxidase (GPOX) activity were reported. AgNPs-treated radish plants had shorter shoots of higher fresh and dry weight and longer roots with lower fresh weight. Treatment with 50 mg·L−1 and 100 mg·L−1 resulted in the highest and lowest accumulation of chlorophylls and carotenoids in the leaves, respectively; however, seedlings treated with 100 mg·L−1 produced less anthocyanins and polyphenols and exhibited lower GPOX activity. In kale, AgNPs-derived seedlings had a lower content of chlorophylls, carotenoids, and anthocyanins but higher GPOX activity of and were characterized by higher fresh and dry shoot weights and higher heterogeneous biometric parameters of the roots. The results of these experiments may be of great significance for broadening the scope of knowledge on the influence of AgNPs on plant cells and the micropropagation of the vegetable species. Future studies should be aimed at testing lower or even higher concentrations of AgNPs and other NPs and to evaluate the genetic stability of NPs-treated vegetable crops and their yielding efficiency.


2021 ◽  
Vol 13 (1) ◽  
pp. 69-80
Author(s):  
Majida Hadi Mahdi Alsaady ◽  
Hussein Ali Salim ◽  
Rakib A. Al-ani ◽  
Hadi M. Aboud ◽  
Jamal Talib M Al Roubaie

In this study, the antagonistic effect of five bacteria genera namely Bacillus, Pseudomonas, Azotobacter, Azospirillum, and Streptomyces isolated from rhizosphere of wheat were evaluated against Fusarium graminearum as potential biocontrol agents in vitro. F. graminearum was molecularly diagnosed using the Polymerase chain reaction (PCR) technique. Each bacteria were tested for the production of catalase enzyme, oxidase enzyme, analysis of starch, analyze of gelatin, and the motility, where Azotobacter, Azospirillum, and Bacillus subtilis were positive for all tested. Fungal inhibition tests were performed by using the dual culture method and agar well diffusion technique. Among them, Streptomyces and Azospirillum exhibited potent inhibition to the growth of F. graminearum (72.14% and 66.42%) respectively, followed by B.pumillus, P.fluorescens, B. subtilis and Azotobacter ( 58.28%, 43.23%, 39.71% and 35.71%) respectively as compared with the control treatment (0.0%).The dry weight of the fungus biomass was decreased with bacteria P. fluorescens, Streptomyces sp, Azotobacter sp, Azospirillum sp, B. subtilis, and B. pumillus which reached (0.114, 0.103, 0.147, 0.101, 0.143, and 0.107 g) respectively compared to the control treatment that was 0. 665 g.


2015 ◽  
Vol 82 (1) ◽  
pp. 268-278 ◽  
Author(s):  
Yannick Raoul des Essarts ◽  
Jérémy Cigna ◽  
Angélique Quêtu-Laurent ◽  
Aline Caron ◽  
Euphrasie Munier ◽  
...  

ABSTRACTDevelopment of protection tools targetingDickeyaspecies is an important issue in the potato production. Here, we present the identification and the characterization of novel biocontrol agents. Successive screenings of 10,000 bacterial isolates led us to retain 58 strains that exhibited growth inhibition properties against severalDickeyasp. and/orPectobacteriumsp. pathogens. Most of them belonged to thePseudomonasandBacillusgenera.In vitroassays revealed a fitness decrease of the testedDickeyasp. andPectobacteriumsp. pathogens in the presence of the biocontrol agents. In addition, four independent greenhouse assays performed to evaluate the biocontrol bacteria effect on potato plants artificially contaminated withDickeya dianthicolarevealed that a mix of three biocontrol agents, namely,Pseudomonas putidaPA14H7 andPseudomonas fluorescensPA3G8 and PA4C2, repeatedly decreased the severity of blackleg symptoms as well as the transmission ofD. dianthicolato the tuber progeny. This work highlights the use of a combination of biocontrol strains as a potential strategy to limit the soft rot and blackleg diseases caused byD. dianthicolaon potato plants and tubers.


2016 ◽  
Vol 27 (2) ◽  
pp. 128-135 ◽  
Author(s):  
J Akte ◽  
S Yasmin ◽  
MJH Bhuiyan ◽  
F Khatun ◽  
J Roy ◽  
...  

Five rice varieties viz. Binadhan-4, Binadhan-5, Binadhan-6, Binadhan-10 and Iratom-24 were evaluated in vitro under different water stress conditions. Several parameters such as germination percentage, shoot length, root length, shoot-root ratio, fresh weight, dry weight, turgid weight, relative water content and proline accumulation were studied. Drought condition was created by MS medium supplemented with five treatments of PEG, with a control such as 0%, 1%, 2%, 3% and 4% of PEG. The highest germination (100%) was found in the variety Binadhan-10 under low water stress conditions induced by 1% PEG. Similarly, the highest percentage of germination was found in all varieties under control condition (0% PEG). The lowest percentage of germination was obtained in the variety Iratom-24. But under severe stress (4% PEG), the highest percentage of germination was found only in the variety Binadhan-10. Moreover, the variety Binadhan-10 was found to be the best at 4% PEG for shoot length, root length, shoot-root ratio, relative water content and also the best at 1% PEG for fresh weight, dry weight, turgid weight. Water stress decreased relative water content and increased proline accumulation in rice. The highest relative water content was recorded in the variety Binadhan-10 and the lowest value recorded in the variety Binadhan-5. The highest proline content was obtained from the binadhan-6 at the highest treatment (4% PEG). Binadhan-10 showed the best performance almost in all the parameters under drought stress because of its own nature of tolerancy.Progressive Agriculture 27 (2): 128-135, 2016


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Hassan O. Shaikhaldein ◽  
Fahad Al-Qurainy ◽  
Mohammad Nadeem ◽  
Salim Khan ◽  
Mohamed Tarroum ◽  
...  

Abstract Silver nanoparticles (AgNPs) are presently the most commonly generated engineered nanomaterials and are found in a wide range of agro-commercial products. The present study was designed to synthesize AgNPs biologically using Ochradenus arabicus leaves and investigate their effect on the morphophysiological properties of Maerua oblongifolia raised in vitro. Physicochemical methods (ultraviolet–visible spectroscopy, Fourier transform infrared spectroscopy, and transmission electron microscopy were performed for characterization and for obtaining microphotographs of the AgNPs. Shoots of M. oblongifolia (2–3 cm) grown in Murashige and Skoog medium supplemented with different concentrations of AgNPs (0, 10, 20, 30, 40, or 50 mg L−1) were used. Following 6 weeks of in vitro shoot regeneration, the shoot number, shoot length, leaf number, fresh weight, dry weight, chlorophyll content, total protein, proline level, and antioxidant enzyme activities of the plants were quantified. We found that 20 mg L−1 AgNPs increased the shoot number, shoot length, fresh weight, dry weight, and chlorophyll content of the plants. The maximum total protein was recorded in plants that were administered the lowest dose of AgNPs (10 mg L−1), while high concentrations of AgNPs (40 and 50 mg L−1) increased the levels of proline and the enzymes superoxide dismutase and catalase. Our results indicate that green-synthesized AgNPs may be of agricultural and medicinal interest owing to their effects on plants in vitro.


Processes ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 482 ◽  
Author(s):  
Nader A. Ashmawy ◽  
Said I. Behiry ◽  
Asma A. Al-Huqail ◽  
Hayssam M. Ali ◽  
Mohamed Z. M. Salem

Phenolic acids and natural extracts, as ecofriendly environmental agents, can be used as bio bactericides against the growth of plant pathogenic bacteria. In this study, isolation trails from infected potato tubers and stems that showed soft rot symptoms in fields revealed two soft rot bacterial isolates and were initially identified through morphological, physiological, and pathogenicity tests. The molecular characterization of these isolates via PCR, based on the 16S rRNA region, was carried out by an analysis of the DNA sequence via BLAST and Genbank, and showed that the soft rot bacterial isolates belong to Pectobacterium carotovorum subsp. carotovorum (PCC1) and Dickeya solani (Ds1). The in vitro results of the tested phenolic acids against the cultured bacterial isolates proved that concentrations of 800, 1600, and 3200 μg/mL were the most effective. Ferulic acid was the potent suppressive phenolic acid tested against the Ds1 isolate, with an inhibition zone ranging from 6.00 to 25.75 mm at different concentrations (25–3200 μg/mL), but had no effect until reaching a concentration of 100 μg/mL in the PCC1 isolate, followed by tannic acid, which ranged from 7.00 to 25.50 mm. On the other hand, tannic acid resulted in a significant decrease in the growth rate of the PCC1 isolate with a mean of 9.11 mm. Chlorogenic acid was not as effective as the rest of the phenolic acids compared with the control. The n-hexane oily extract (HeOE) from Bougainvillea spectabilis bark showed the highest activity against PCC1 and Ds1, with inhibition zone values of 12 and 12.33 mm, respectively, at a concentration of 4000 μg/mL; while the HeOE from Citharexylum spinosum wood showed less activity. In the GC/MS analysis, nonanal, an oily liquid compound, was found ata percentage of 38.28%, followed by cis-2-nonenal (9.75%), which are the main compounds in B. spectabilis bark HeOE, and 2-undecenal (22.39%), trans-2-decenal (18.74%), and oleic acid (10.85%) were found, which are the main compounds in C. spinosum wood HeOE. In conclusion, the phenolic acids and plant HeOEs seem to raise the resistance of potato plants, improving their defense mechanisms against soft rot bacterial pathogens.


Author(s):  
Anam Choudhary ◽  
Shabbir Ashraf

AbstractThe present study was carried out to evaluate the effect of bioagents and organic amendments in suppressing the dry root rot of mungbean incited by Rhizoctonia bataticola. The locally isolated pathogen and fungal biocontrol agents were identified based on morphological and molecular characterization. These identified bioagents were tested in vitro, and the highest mycelial inhibition was recorded in dual culture assay by Trichoderma harzianum (74.44%), and among organic amendments, maximum mycelial inhibition was found in neem cake (61.11%). In a greenhouse study, T. harzianum + neem cake effectively enhanced the percent germination (93.33%) and decreased the percent disease mortality (11.67%) than the other treatments. The morphological parameter like plant height (57.50 cm), dry weight (22.83 g) root nodules (51), pods/plant (58), and 100-seed weight (5.78 g) were found to be at the maximum in this combined application. Physiological pigments viz. chlorophyll (2.41 mg/g) and carotenoids (0.19 mg/g), protein content (5.85 mg/g), and leghemoglobin (11.75 mg/g) were also found to be maximum in T. harzianum + neem cake and minimum phenol content (1.41 mg/g). The study concludes that T. harzianum + neem cake can be recommended as an effective approach for the management of dry root rot of mungbean.


1981 ◽  
Vol 61 (3) ◽  
pp. 665-671 ◽  
Author(s):  
G. LAFOND ◽  
L. E. EVANS

The effect of the "leafless" mutations (in which tendrils replace leaflets, af, and the stipules are reduced to a vestigial form, st) upon chlorophyll content, total protein, soluble protein, ribulose biphosphate carboxylase activity, and fresh weight/dry weight ratio were studied. Comparison of three near-isogenic lines of Century, Freezer and Trapper for the genotypes af af st st (leafless), af af + + (semi-leafless) and + + st st (reduced stipules) were compared with the conventional (+ + + +) plants. Chlorophyll contents were reduced by as much as 50% in the leafless phenotypes, as compared to the leafed plants. The leafless phenotype showed significantly higher levels of total nitrogen than the leafed plants. Tendrils had significantly lower levels of soluble protein than leaflets in two of the three cultivars examined. The fresh weight/dry weight ratio was significantly higher in the leafless phenotypes than the leafed types as a result of changes in morphology, going from a leaflet to a tendril. The internal arrangement of cells in the tendril was typical of pith and cortex tissue with very few intercellular spaces between the parenchyma cells. The intercellular space index within the tendrils was significantly lower than in the leaflet. In vitro measurements of ribulose biphosphate carboxylase activity were calculated per unit fresh weight and per unit chlorophyll. No significant differences were found between the different phenotypes per unit fresh weight; however, when the activity was measured per unit chlorophyll, the values for tendrils were significantly higher than for leaflets.


HortScience ◽  
2007 ◽  
Vol 42 (2) ◽  
pp. 325-328 ◽  
Author(s):  
Jeffrey Adelberg ◽  
Maria Delgado ◽  
Jeffrey Tomkins

Two tetraploid and two diploid genotypes of Hemerocallis spp. were micropropagated on an orbital shaker in Murashige and Skoog liquid medium in a factorial combination of two sucrose concentrations (90 mm and 180 mm), two 6-benzylaminopurine (benzyladenine) concentrations (0.32 μm and 3.2 μm), at two densities (57 explants/L and 171 explants/L), in the presence (0.32 μm) and absence of α-cyclopyl-α-[4-mehtoxyphenyl]-5-pyrimididinmethanol (ancymidol). There were linear relationships between fresh weight and water use (R 2 = 0.800, P < 0.0001), dry weight and sucrose use (R 2 = 0.636, P < 0.0001), and relative dry weight (dry weight/fresh weight = relative dry weight) to concentration of sucrose residual in medium after culture (R 2 = 0.553, P < 0.0001). Eighty-five percent of the water used and 74% of the sucrose used were incorporated as plant fresh weight and dry weight, respectively. A 1% increase in percent sucrose residual (mass/volume in spent medium) was correlated to an increase of 1.8% relative dry weight over the range 7% to 22% relative dry weight. In vessels with 90 mm initial sucrose, where the most growth had occurred (>15 g fresh weight), sucrose was depleted (<0.2% sucrose) and plantlets had the lowest relative dry weight (≈6.9%). In vessels from 180 mm initial sucrose, with similarly high fresh weight, plantlets had 12.0% relative dry weight with 2.1% sucrose residual in medium. Fresh weight, dry weight, or relative dry weight of plantlets in the laboratory did not correlate with subsequent survival or growth in the greenhouse. Plantlets grown without ancymidol at the lower benzyladenine concentration acclimatized to the greenhouse with 93% survival. However, greenhouse survival of plants grown with ancymidol and a higher level of benzyladenine was only 4%. ‘Barbara Mitchell’ was the largest plant in the laboratory, but often had poorest growth in the greenhouse. When optimizing a liquid micropropagation protocol for larger vessels, sucrose and water requirements may be directly related to targeted biomass yield, but each genotype needs to be handled independently with ex vitro validation of plant vigor.


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