Individual Inoculation Research Articles

EFFECT OF MYCORRHIZA AND RHIZOBIUM INOCULATION ON THE GROWTH AND YIELD OF MUNG (VIGNA RADIATA) PLANT

In this study, the effect of Rhizobium and mycorrhizal fungal spores were examined on Vigna radiata (Mung bean). Seeds of Mung bean var. PDM-139-SAMRAT were sown in plastic pots, in the mixture of half soil and half sand. Rhizobium and mycorrhizal fungal spores inoculated individually and in combination with mung seeds. After germination data have been reported for plant height, leaf area, number of root nodules and pods, chlorophyll amount and yield measured after 30,45,60,75,90 and 120 days of sowing. Results of these experiments showed that Rhizobium and mycorrhiza positively affected the growth and yield of mung plant. Combined inoculation of Rhizobium and mycorrhiza shows better results in comparison to their individual inoculation. Mixture of Rhizobium and mycorrhizal spores improve the growth, yield, number of root nodules and pods, leaf area and chlorophyll amount of mung plant.

Physiological response of Arizona cypress to Cd-contaminated soil inoculated with arbuscular mycorrhizal fungi and plant growth promoting rhizobacteria

Increasing some industrial activities has been constantly contaminated the soil with different toxic metals leading to serious environmental concerns. However, some beneficial soil microorganisms would be useful tools for reducing toxic effects of heavy metals without producing toxic residuals. Therefore, present study was conducted to evaluate potential role of Pseudomonas fluorescens and arbuscular mycorrhizal fungi (AMF) in reducing cadmium toxicity in the Arizona cypress seedlings both individually and in combination. Factorial experiment was conducted based on a completely randomized design with three factors comprising AMF inoculation (Rhizophagus irregularis or Funneliformis mosseae or a mixture of both species, and non-inoculated controls), bacterial inoculation (P. fluorescens or Non-inoculated), and five levels of Cd (0, 5, 10, 15, and 20 mg kg−1) using three replications. Results of this study showed that, Arizona cypress growth decreased when exposed to high levels of Cd contamination. However, co-inoculation plants with all mycorrhizae and P. fluorescens grown under the highest levels of Cd contamination, showed increased photosynthetic pigments. Furthermore, AMF and P. fluorescens increased ascorbate peroxidase activity, which is responsible for the elimination of H2O2 when plants exposed to Cd stress. Moreover, high levels of Cd contamination negatively influenced phosphorus uptake by the plants, especially in control plants. Moreover, in seedlings inoculated with mycorrhizal fungi, accumulation of Cd was found to be less, apparently as a result of AMF modification of the influx of Cd into the host plants, as confirmed by reduced hydrogen peroxide and enhanced antioxidant enzyme activities compared to the control plants. AMF treatments increased glomalin related soil proteins concentration compared to the control plants. Also, the highest amount of glomalin production was observed in two species of Mix and FM. In conclusion, either co-inoculation with AMF and P. fluorescens or individual inoculation with AMF could potentially ameliorate harmful effects of Cd on Arizona cypress growth. .

Alleviation of zinc deficiency in wheat inoculated with root endophytic fungus Piriformospora indica and rhizobacterium Pseudomonas putida

Plant growth, grain yield, and the nutritional grain quality reduce in Zinc (Zn)-deficient soils. As a practical approach, the utilization of plant growth-promoting microorganisms offers a promising approach to cope with Zinc deficiency. This study was carried out to determine the effects of endophytic fungus Piriformospora indica and rhizobacterium Pseudomonas putida on growth, nutrient status, and antioxidant enzyme activities of two wheat (Triticum aestivum L.) genotypes under Zn deficiency. The experiment was conducted using a completely randomized factorial design with three replications and three treatments: wheat genotypes [Zn-efficient (H-Zn) genotype, Azadi and Zn-inefficient (L-Zn) genotype, Niknejad]), Zn concentrations (0 and 2 μmol Zn L−1) and microbial inoculations (P. indica and P. putida). Under Zn deficiency, P. indica, P. putida, and dual inoculation of P. indica with P. putida significantly increased the shoot dry weight of L-Zn genotype up to 10.3%, 25.6% and, 15.4% compared to control plants, respectively. Inoculation of P. indica led to an increase in thinner and highly-branched roots and subsequently increased Zn uptake in the shoot of L-Zn genotype under Zn deficiency. Under such condition, individual inoculation of L-Zn genotype with P. putida and P. indica increased peroxidase activity by 85.7% and 40% compared with non-inoculated plants. Malondialdehyde content of both wheat genotypes inoculated with P. indica was significantly decreased compared to the non-inoculated plants. Generally, depending on the wheat genotype, P. indica and P. putida can increase plant tolerance by affecting only part of the tolerance mechanisms (including antioxidant and non-antioxidant mechanisms) under Zn deficiency stress. In summary, P. indica and P. putida could improve the fitness of the L-Zn genotype under Zn-deficiency stress.

Impact of the alkaloid colletotrichumine A on the pathogenicity of Colletotrichum capsici in Capsicum annum L

Herein we report a study examining the effects of colletotrichumine A, an indole-pyrazine alkaloid isolated from the anthracnose pathogen Colletotrichum capsici, on chilli plants. A colletotrichumine A-pathogen combination was more toxic to the host than individual inoculations of colletotrichumine A or the pathogen. The colletotrichumine A-pathogen combination led to an increased activity of defense related enzymes viz. PPO and SOD, while levels of the lignification enzymes PAL and PO decreased. Higher levels of phenols including catechin and ferulic acid were also observed with the colletotrichumine A-pathogen combination compared to individual treatment. The likely role of colletotrichumine A during chilli anthracnose infection is supported by histochemical analysis of infected plants that showed increased cell death after infection.

Individual and combined application of Cu-tolerant Bacillus spp. enhance the Cu phytoextraction efficiency of perennial ryegrass

Forage grasses have recently received a remarkable amount of attention as promising candidates for decontaminating metal-polluted soils, but this strategy is time-consuming and inefficient. The present study aimed to address the beneficial effects of screened plant growth-promoting rhizobacteria (PGPR) strains Bacillus sp. EhS5 and EhS7 on perennial ryegrass and tall fescue. Single or combined inoculation considerably increased the biomass yield and Cu content of inoculated ryegrass compared with uninoculated plants, thereby enhancing the extraction efficiency at different Cu contamination levels. Bioaugmentation did not show a positive impact on the improvement of fescue’s phytoextraction efficiency. Principal component analysis (PCA) and Pearson correlation coefficient results identified root development and photosynthesis as the key variables influencing ryegrass biomass. Antioxidant activities and Cu bioavailability are the key variables influencing Cu accumulation. The inoculated ryegrass showed improved photosynthetic status as the photosystem II system efficiency parameters increased and energy dissipation in the form of heat (DIo/RC) decreased with the help of PGPR. The root length, diameter, surface area, and forks of inoculated ryegrass increased remarkably. The levels of scavengers of reactive oxygen species were enhanced in these plants. Moreover, PGPR significantly increased soil Cu bioavailability by secreting siderophores and organic acid and by increasing soil organic carbon content. Dual inoculation showed better results than individual inoculation in improving ryegrass growth and Cu translocation under high Cu contamination level according to PCA. This study systematically explored the effects and mechanisms of the Bacillus–ryegrass combined remediation and provided a novel method for cleaning Cu-contaminated sites.

Pathogenicity of Meloidogyne incognita and Fusarium oxysporum f. sp. vasinfectum on Growth and Yield of Two Okra Varieties Cultivated in Ghana

The interaction of the fungus, Fusarium oxysporum f. sp. vasinfectum (FOV), and the nematode, Meloidogyne incognita, on wilt disease on “Essoumtem” and Clemson spineless okra varieties, was examined in pot and field experiments from September 2016 to June 2017, in the University of Ghana farms. Four-week-old “Essoumtem” and Clemson spineless seedlings for pot experiment and one-week-old “Essoumtem” and Clemson spineless seedlings for field experiment were inoculated with fungus, Fusarium oxysporum, and nematode, Meloidogyne incognita. The individual, simultaneous, and sequential inoculation of second stage juveniles (at 1000 J2/kg soil) of Meloidogyne incognita and Fusarium oxysporum (1.1 × 106 cells/kg soil) resulted in significant reduced plant growth parameters (plant height, plant girth, chlorophyll content, fresh and dry shoot weights, and fresh and dry root weights). Maximum suppression in plant growth parameters was observed in plants that received NF21 (Fusarium oxysporum inoculated 21 days after Meloidogyne incognita on okra) and F21 (fungus inoculated 21 days after seedling emergence) treatments for pot and field experiments, respectively. The least suppression of plant growth parameters was observed in separate inoculations of the two pathogens for both pot and field experiments. Maximum suppression in yield parameters was observed in okra plants that received NF21 and F21 treatments for pot and field experiments, respectively. Minimal yield suppression was observed for individual inoculations (N and F treatments) in both pot and field experiments. The highest severity of wilt disease was observed on okra plants that received NF21 and F21 treatment in both pot and field experiments. Plants in control plots had higher yields and the least wilt incidences (0.0%).

Isolation and Characterization of Indigenous Plant Growth-Promoting Rhizobacteria (PGPR) from Cardamom Rhizosphere.

The present study was conducted to explore the native plant growth-promoting (PGP) bacteria from cardamom rhizosphere in few districts of Kerala and Tamilnadu under cardamom cultivation. The isolates obtained were screened for their PGP characteristics and their beneficial effect on cardamom was evaluated. Of the total 88 isolates, ten were screened as promising based on their performance in growth promoting attributes such as production of indole acetic acid, gibberellic acid, siderophore, hydrogen cyanide, heavy metal tolerance and antibiotic resistance. Diazotrophy of the screened isolates were tested by nitrogenase assay and evaluated using the diversity of nif genes. Genetic analysis was carried out to assess the phylogenetic relationship using 16S rRNA sequencing. The phylogenetic analysis exhibited clear clustering of isolates into three phyla namely Firmicutes, Actinobacteria and γ-proteobacteria. Majority of the isolates were grouped into Bacillus and Pseudomonas at genus level. Three different plant inoculation study at nursery and field level, viz., Bacillus subtilis TAUC1, Bacillus subtilis TAUC2 and Pseudomonas putida TAUC10. The combined inoculation of bioinoculants were superior over individual inoculation with respect to growth, soil and plant nutrient content, biochemical constituents, rhizosphere population, soil enzyme activities and yield. Hence the present study reveals the potential effect of PGPR for bioinoculant production for enhancing growth and development of cardamom under field conditions.

Tolerance of five mango cultivars to malformation disease in Mexico

Mango malformation (Fusarium spp.) is one of most the severe diseases and is difficult to control in dry tropical areas worldwide. In Mexico, the disease reduces yields by up to 40–50%. In this study, the tolerance of two current mango cultivars (‘Ataulfo’ and ‘Haden’) and three recently introduced to Mexico (‘Rosigold’, ‘Mallika’ and ‘Nam Doc Mai’) to infection by Fusarium subglutinans (Fs) and F. mexicanum (Fm) was determined with a standardized inoculation procedure. The experiment was repeated and carried out in an experimental nursery located in Huamuxtitlan, Guerrero, Mexico, in 2015 and 2016. Each pathogenicity test was conducted on five healthy 6-month-old mango plants per cultivar by infiltration, singly and in combination, of Fs and Fm conidial suspension into the apical bud and the first three subapical (axillary) buds. The combination of Fusarium species induced higher severity (30.8%) than individual inoculation, independent of the cultivar. The incubation period before typical vegetative malformation symptoms was longer in ‘Ataulfo’ (267 d) than the rest of the cultivars (168–198 d). Comparatively, ‘Ataulfo’ also showed lower incidence (23.3%), disease severity index (3.6%), final severity (Yf = 0.6), infection rate (b−1 = 0.039) and area under the disease progress curve (AUDPC = 0.53). According to the severity scale used, ‘Ataulfo’ was tolerant, and ‘Nam Doc Mai’ and ‘Rosigold’ were susceptible, while ‘Mallika’ and ‘Haden’ were highly susceptible.

Synergistic inoculation of Azotobacter vinelandii and Serendipita indica augmented rice growth

In the rhizosphere, microbes act as crucial constituent for plant growth and development. The root-endophytic plant growth-promoting fungus-Serendipita indica and nitrogen fixing bacterium Azotobacter vinelandii are well known for plant growth promotion and stress alleviation. Individual inoculation of S. indica or A. vinelandii strain SRIAz3 has already been reported to augment plant growth. Therefore, it would be interesting to investigate the mutual interaction among these two microbes along with their symbiotic influence on growth of rice plant. The present study explores the interaction of S. indica and A. vinelandii strain SRIAz3 under in vitro condition and perceive their cumulative effect on rice growth. Differential growth response of S. indica was observed after inoculation of A. vinelandii strain SRIAz3 on different days. An enhanced S. indica growth in terms of hyphal radius and dry cell weight was found when SRIAz3 was inoculated 7 days after fungal inoculation. Moreover, confocal microscopy analysis revealed that A. vinelandii strain SRIAz3 cell-free supernatant increased S. indica spore germination. The sequential inoculation of A. vinelandii strain SRIAz3 on seventh day after S. indica inoculation in rice variety IR64 demonstrates better growth in terms of root-shoot biomass and chlorophyll content as compared to the non-inoculated and to singly inoculated plants. These findings recommend the sequential inoculation of S. indica followed by A. vinelandii strain SRIAz3 for the enhancement of rice growth.

Fungal endophytes promote the accumulation of Amaryllidaceae alkaloids in Lycoris radiata.

Lycoris radiata is a main source of Amaryllidaceae alkaloids; however, the low content of these alkaloids in planta remains a limit to their pharmaceutical development and utilization. The accumulation of secondary metabolites can be enhanced in plants inoculated with fungal endophytes. In this study, we analysed the diversity of culturable fungal endophytes in different organs of L. radiata. Then, by analysing the correlation between the detectable rate of each fungal species and the content of each tested alkaloid, we proposed several fungal candidates implicated in the increase of alkaloid accumulation. This was verified by inoculating these candidates to L. radiata plants. Based on the results of two independent experiments conducted in May 2018 and October 2019, the individual inoculation of nine fungal endophytes significantly increased the total content of the tested alkaloids in the entire L. radiata plants. This is the first study in L. radiata to show that fungal endophytes are able to improve the accumulation of various alkaloids. Therefore, our results provide insights into a better understanding of interactions between plants and fungal endophytes and suggest an effective strategy for enhancing the alkaloid content in the cultivation of L. radiata.

Effect of Compatible and Incompatible Endophytic Bacteria on Growth of Chickpea Plant

Chickpea is one of the important pulse crops among legumes due to its high protein content. During the last few decades chickpea production has declined because of various biotic and abiotic factors. To increase its production farmers are relying on the traditional methods (using chemical fertilizers) that pollute the environment. An alternative to chemical fertilizers is the eco-friendly process of endophytic inoculation. Compatible endophytic coinoculations improve plant growth as compared to single inoculation due to the synergistic performance of the constituent bacteria. In the current study, the compatibility of six bacterial inoculants (BM5 (rhizobial), BP2 and P36 (phosphate solubiliser), RE2, HE8, and ME9 (other endophytes) was tested. Among these bacterial inoculants, endophyte ME9 was found to be compatible with phosphate solubilising bacteria (P36) and rhizobial culture BM5. However, the endophytic bacteria RE2 and HE8 were found to be incompatible with phosphate solubilising bacteria and rhizobial bacteria. Further, individual inoculation, combined compatible and combined incompatible inoculants were applied to chickpea seeds in the pot house experiment. The results revealed that among all the inoculations, compatible bacterial consortia (ME9, P36 and BM5) produced highest increase in shoot (225%) and root dry weight (600 %) and grain weight (250 % ) compared to the control group. The incompatible inoculations were ineffective in improving the root dry weight, shoot dry weight, and grain weight in comparison to the respective individual inoculations.

Proteus mirabilis causing cellulitis in broiler chickens.

Given the need to understand the virulence profile of Proteus mirabilis isolates from cellulitis in broiler chickens and their ability to cause lesions, the present study aimed to characterize genotypically and phenotypically the virulence profiles of two strains of P. mirabilis isolated from cellulitis in broilers, as well as to evaluate their ability to experimentally reproduce the lesions in vivo. The strain with the highest virulence potential (LBUEL-A33) possessed mrpA, pmfA, ucaA, atfA (fimbriae), zapA, ptA (proteases), hpmA (hemolysin), and ireA (siderophore) genes, formed a very strong biofilm, and expressed the pattern of aggregative adhesion and cytotoxicity in Vero cells. The strain with the lowest virulence potential (LBUEL-A34) did not present the pmfA and ucaA genes, but expressed the pattern of aggregative adhesion, formed a strong biofilm, and did not show cytotoxicity. Both strains developed cellulitis in an animal model within 24h post-inoculation (PI), and the degree of lesions was not significantly altered up to 120h PI. The LBUEL-A33 strain was also inoculated in combination with an avian pathogenic Escherichia coli (APEC 046), and the lesions showed no significant changes from the individual inoculation of these two strains. Histological analysis showed that the LBUEL-A33 strain developed characteristic cellulitis lesions. Thus, both strains of P. mirabilis isolated in our study have several virulence factors and the ability to develop cellulitis in broilers.

USING SOME BIOFERTILIZATION TREATMENTS TO PROMOTE YIELD AND BERRIES QUALITY OF FLAME SEEDLESS GRAPEVINES (Vitis vinifera L.)

Flame Seedless cultivar is one of the most popular grape cultivar in Egypt. However, in Minia region, it faces some problems such as poor yield and poor coloration of berries, which in turn negatively affect marketing of such grapevine cv. The present study was conducted during two seasons 2017 and 2018 on Flame seedless grapevines in order to study the possibility of using single and combined inoculation with Arbuscular Mmycorrhizal fungi (AMF), Azospirillum brasilense bacteria (AZSB) and Azotobacter chrococcum bacteria (AZBB) on improving productivity and fruit quality of Flame Seedless grapevines grown clay soil under Minia region conditions, Egypt. The obtained results confirmed that inoculation the vines with the three examined microorganisms (AMF, AZSB and AZBB) individually or in combination was remarkably improved the yield and its components, berries physical properties and berries chemical properties comparison to un-inoculated vines. Furthermore, any combined inoculation was more effectiveness on yield and berries physical and chemical than the individual inoculation, during the two experimental seasons. The vines inoculated with the mixture of the three microorganism's AFM+AZSB+AZBB in-combination gave the highest yield and best berries physical and chemical properties.

Beneficial Endophytic Bacteria-Serendipita indica Interaction for Crop Enhancement and Resistance to Phytopathogens.

Serendipita (=Piriformospora) indica is a fungal endophytic symbiont with the capabilities to enhance plant growth and confer resistance to different stresses. However, the application of this fungus in the field has led to inconsistent results, perhaps due to antagonism with other microbes. Here, we studied the impact of individual bacterial isolates from the endophytic bacterial community on the in vitro growth of S. indica. We further analyzed how combinations of bacteria and S. indica influence plant growth and protection against the phytopathogens Fusarium oxysporum and Rhizoctonia solani. Bacterial strains of the genera Bacillus, Enterobacter and Burkholderia negatively affected S. indica growth on plates, whereas Mycolicibacterium, Rhizobium, Paenibacillus strains and several other bacteria from different taxa stimulated fungal growth. To further explore the potential of bacteria positively interacting with S. indica, four of the most promising strains belonging to the genus Mycolicibacterium were selected for further experiments. Some dual inoculations of S. indica and Mycolicibacterium strains boosted the beneficial effects triggered by S. indica, further enhancing the growth of tomato plants, and alleviating the symptoms caused by the phytopathogens F. oxysporum and R. solani. However, some combinations of S. indica and bacteria were less effective than individual inoculations. By analyzing the genomes of the Mycolicibacterium strains, we revealed that these bacteria encode several genes predicted to be involved in the stimulation of S. indica growth, plant development and tolerance to abiotic and biotic stresses. Particularly, a high number of genes related to vitamin and nitrogen metabolism were detected. Taking into consideration multiple interactions on and inside plants, we showed in this study that some bacterial strains may induce beneficial effects on S. indica and could have an outstanding influence on the plant-fungus symbiosis.

Açaí palm seedling growth promotion by rhizobacteria inoculation.

Lower growth rate of the açaí palm seedlings limits the crops' commercial expansion. The goal was evaluating the biometry, biomass accumulation, nutrient contents, chlorophyll-a fluorescence, and gas exchange in açaí seedlings inoculated with rhizobacteria. The treatments were individual inoculations of the seven rhizobacteria isolates and one control (without inoculation) on the roots. Biometry and biomass data were submitted to cluster analysis to separate the isolates into groups according to the similarity degree, and groups' means were compared through the SNK test. Three groups were formed; group 1 was composed of the control; group 2 of the UFRA-35, UFRA-38, UFRA-58, UFRA-61, UFRA-92, and BRM-32111 isolates; and group 3 was composed of the BRM-32113 isolate. Group 2 and 3 isolates promoted an increase in growth, biomass accumulation, higher levels of nutrients and chlorophyll, and improvements in the gas exchange and chlorophyll-a fluorescence in comparison with the control. The results evidenced that the rhizobacteria accelerate the growth, increase the photosynthetic efficiency, and induce the leaf nutrient accumulation in açaí palm seedlings. The rhizobacteria inoculation can contribute to the sustainable management of the açaí palm seedling production in nurseries.

Management of bacteria Pectobacterium carotovorum, Xanthomonas campestris pv. carotae, and fungi Rhizoctonia solani, Fusarium solani and Alternaria dauci with silicon dioxide nanoparticles on carrot

ABSTRACT Diseases of carrot (Daucus carota L.) that cause yield losses include bacterial soft-rot incited by Pectobacterium carotovorum pv. carotovorum (Jones) Waldee; bacterial leaf blight incited by Xanthomonas campestris pv. carotae (Pammel) Dowson; fungal leaf blight incited by Alternaria dauci (J.G. Kühn) J.W. Groves & Skolko; rot incited by Fusarium solani (Martius) Sacc., and crown rot incited by Rhizoctonia solani Kuhn. Nanoparticles are used to increase plant growth and provide protection against plant pathogens on various crops, but their effectiveness on carrot is not well understood. Effect of silicon dioxide nanoparticles (SiO2 NPs) after seed were primed, or applied to foliage, on inhibition of P. carotovorum, X. campestris pv. carotae, A. dauci, F. solani or R. solani, on growth, chlorophyll, carotenoid and proline contents of carrot were determined. Inoculation of plants with all pathogens reduced shoot and root dry weights, and chlorophyll and carotenoid contents over uninoculated controls. Inoculation of R. solani caused the greatest reduction (65.18%) in root dry weight and X. campestris pv. carotae the least (20.13%). Seed priming or foliar application with SiO2 NPs increased plant growth, and chlorophyll and carotenoid contents in inoculated plants, and the uninoculated control. Foliar application was better than seed priming in increasing growth, and chlorophyll and carotenoid contents of inoculated plants. The least increase in root dry weight (17.09%) was when plants derived from SiO2 NPs primed seed were inoculated with P. carotovorum, and the most was with foliar-applied SiO2 NPs against R. solani (85.29%). Individual inoculation of plants with pathogens caused increased proline content over the uninoculated control. Proline contents were further increased by the application of SiO2 NPs. Soft rot and bacterial blight index was 3 of 5 when plants were inoculated with P. carotovorum and X. campestris pv. carotae, respectively. Leaf blight/crown rot and root-rot indices were 4 of 5 when inoculation was with A. dauci, F. solani, and R. solani. Application of SiO2 NPs could be useful for the control of bacteria and fungi infecting carrot.

Broad and systemic immune-modulating capacity of plant-derived dsRNA.

Double-stranded RNA (dsRNA) is well characterized as an inducer of anti-viral interferon responses. We previously reported that dsRNA extracted from a specific edible plant possesses an immune-modulating capacity to confer, in mice, resistance against respiratory viruses, including the H1N1 strain of the influenza A virus (IAV). We report here that the systemic immune-activating capacity of the plant-derived dsRNA protected mice from infection by a highly virulent H5N1 strain of the IAV. In addition, subcutaneous inoculation of the dsRNA together with the inactivated virion of the H5N1 strain of the IAV suppressed the lethality of the viral infection as compared with individual inoculation of either dsRNA or HA protein, suggesting its potential usage as a vaccination adjuvant. Moreover, intra-peritoneal inoculation of the dsRNA limited the growth of B16-F10 melanoma cells through the activation of NK cells in murine models. Taken together, this study demonstrated the systemic immune-modulating capacity of a plant-derived dsRNA and its potential for nucleic acid-based clinical applications.

Sunflower response to inoculation with single and mixed species of arbuscular mycorrhizal fungi: Agronomic characteristics

The impact of indigenous arbuscular mycorrhizal fungi (AMF) on agronomic characteristics of sunflower (Helianthus annuus L.) was evaluated in a pot experiment. The indigenous AMF, including Glomus intraradices, Glomus mosseae, and Glomus viscosum, were isolated from an agricultural field in which cotton and sunflower plants were grown. The most abundant species (G. viscosum) was multiplied in a monospecific culture. Sunflower plants were inoculated with the mixture of three selected AMF species or solely with G. viscosum. The number of leaves, shoot length, head diameter, above ground biomass, and seeds mass were significantly higher in the plant inoculated with AMF mixture followed by individual inoculation with G. viscosum followed by the control. AMF mixture outperformed the G. viscosumby increasing mycorrhizal dependency and mycorrhizal inoculation effect of sunflower. The results indicate that AMF mixture could be considered as a good inoculum for improving growth and yield of sunflower in sustainable agriculture.

ACC Deaminase Producing PGPR Bacillus amyloliquefaciens and Agrobacterium fabrum along with Biochar Improve Wheat Productivity under Drought Stress

Drought stress retards wheat plant’s vegetative growth and physiological processes and results in low productivity. A stressed plant synthesizes ethylene which inhibits root elongation; however, the enzyme 1-Aminocyclopropane-1-Carboxylate (ACC) deaminase catabolizes ethylene produced under water stress. Therefore, the ACC deaminase producing plant growth promoting rhizobacteria (PGPR) can be used to enhance crop productivity under drought stress. Biochar (BC) is an organically active and potentially nutrient-rich amendment that, when applied to the soil, can increase pore volume, cation exchange capacity and nutrient retention and bioavailability. We conducted a field experiment to study the effect of drought tolerant, ACC deaminase producing PGPR (with and without timber waste BC) on plant growth and yield parameters under drought stress. Two PGPR strains, Agrobacterium fabrum or Bacillus amyloliquefaciens were applied individually and in combination with 30 Mg ha−1 BC under three levels of irrigation, i.e., recommended four irrigations (4I), three irrigations (3I) and two irrigations (2I). Combined application of B. amyloliquefaciens and 30 Mg ha−1 BC under 3I, significantly increased growth and yield traits of wheat: grain yield (36%), straw yield (50%), biological yield (40%). The same soil application under 2I resulted in greater increases in several of the growth and yield traits: grain yield (77%), straw yield (75%), above- and below-ground biomasses (77%), as compared to control; however, no significant increases in chlorophyll a, b or total, and photosynthetic rate and stomatal conductance in response to individual inoculation of a PGPR strain (without BC) were observed. Therefore, we suggest that the combined soil application of B. amyloliquefaciens and BC more effectively mitigates drought stress and improves wheat productivity as compared to any of the individual soil applications tested in this study.

Quantitative proteomic profiling of ochratoxin A repression in Penicillium nordicum by protective cultures

Dry-cured meat products are usually contaminated with moulds during ripening. Although fungal development contributes to the desired sensory characteristics, some moulds, such as Penicillium nordicum are able to produce ochratoxin A (OTA) on meat products. Therefore, strategies to prevent OTA contamination in ripened meat products are required. Microorganisms isolated from these meat products can be adequate as biocontrol agents, given that no negative sensory impact is expected. The PgAFP antifungal protein-producer Penicillium chrysogenum (Pc) and Debaryomyces hansenii (Dh) have been shown to successfully inhibit toxigenic moulds. However, scarce information about the mechanism of action of these biocontrol agents on toxigenic mould inhibition is available. Comparative proteomic analysis is a powerful tool to investigate the physiological response of microorganisms to stimuli. Proteomic analysis was carried out on P. nordicum co-cultured with Pc, Dh, PgAFP, and their combinations on a dry-cured ham-based medium. Additionally, OTA production by P. nordicum in the different cultures was measured. The individual inoculation of Pc or Dh repressed OTA production by P. nordicum by 5 and 3.15 fold, respectively. A total of 2844 unique P. nordicum proteins were identified by proteomic analysis. The impact of the biocontrol agents on the proteome of P. nordicum was higher for Pc-containing cultures, followed by Dh-containing treatments. PgAFP alone had minimal impact on the proteome of P. nordicum. Proteomic analyses indicated Pc repressed P. nordicum OTA production through nutrient competition, potentially reducing glucose availability. Data also suggest that Dh and Pc inhibited P. nordicum through cell wall integrity impairment. Both Pc and Dh seem to hamper P. nordicum secondary metabolism (SM) as indicated by lower levels of MAP kinases and SM-associated proteins found in the co-inoculated P. nordicum. This work paves the way to use antifungal agents in the most efficient way to prevent OTA formation in meat products.