Potential Bioagent Research Articles

Biological characterization and complete genome analysis of a novel Stenotrophomonas maltophilia phage vB_SM_ytsc_ply2008005c

Multidrug-resistant bacteria have become a major threat to global public health. Bacteriophages are regarded as a promising substitute. Here, we present a novel lytic Stenotrophomonas maltophilia phage, vB_SM_ytsc_ply2008005c, which was isolated from sewage water samples in Qingdao, east China. Virion morphology of phage particles indicated that ply2008005c has an icosahedral head (56 ± 5 nm in diameter) and a noncontractile sheathed tail (129 ± 6 nm in length), which are the typical characteristics of phages belonging to the family Siphoviridae. Phage ply2008005c could be used for phage therapy for its stability in a wide pH (4 to 12) range and high temperature (up to 70°C) environment. Genome analysis revealed that ply2008005c has a circular double-strand DNA of 42,318 bp with a G+C content of 63.02%. It shared the closest relationship with phage vB_PaeS_PAO1_Ab18, but the homology coverage is just 20%. There were 54 open reading frames predicted in its genome, including three unique proteins and 34 functional genes in different modules. The phylogenetic analysis revealed that ply2008005c forms a distinct branch of the family Siphoviridae. These results demonstrated that ply2008005c was supposed to be a representative new member within the family Siphoviridae, which could be considered a potential bioagent against multidrug-resistant S. maltophilia.

Pseudomonas fluorescens VSMKU3054 mediated induced systemic resistance in tomato against Ralstonia solanacearum

Plant growth-promoting rhizobacteria (PGPR) are potential bio agents for the suppression of various soil-borne diseases in crop plants and considered as viable alternative to chemical pesticides. The selected Pseudomonas fluorescens isolate VSMKU3054 is an effective biological control inoculum for the suppression of wilt disease of tomato incited by Ralstonia solanacearum by inducing plant defense enzymes viz., peroxidase (POX), polyphenol oxidase (PPO), lipoxygenase (LOX), phenylalanine ammonia-lyase (PAL) and total phenol content. The highest level of defense enzymes viz., POX, PAL, PPO, LOX and total phenol contents were observed in tomato seedlings treated with P. fluorescens at 24h, 36h, 36h, 48h and 24h after challenge inoculation of R. solanacearum, respectively. Whereas application of P. fluorescens alone in tomato plants also brought about induction of higher levels of POX, PAL, LOX and total phenol contents, and a moderate level of PPO activity compared to pathogen inoculated plants and control plants. The maximum induction of four prominent PPO isoforms was observed in tomato plants upon the treatment of P. fluorescens VSMKU3054 and challenged with R. solanacearum. Thus, this study showed that induction of defense-related genes by P. fluorescens plays an important role against R. solanacearum.

Evolving Dimension of Security: Bioterrorism

Bioterrorism became a burning issue in the USA after the human-induced incidence of Anthrax and the attack on WTO in 2001. At present, the world is trapped in the COVID 19 pandemic having an estimated monetary loss of 76.69 billion USD, engulfed more than 4.5 million people, and 211 million suffering to date. There is increasing concern toward bioterrorism globally which can happen either intentionally or due to poor laboratory practices. In recent decades technological progress in bioscience has simplified the development of bioweapons. Moreover, the advancement of genetic engineering is chronic biologically. Over a hundred pathogens have been identified as possible bioterrorism agents. The research article aims to explore bioterrorism as an evolving dimension of threat to the public and national security in developing countries like Nepal. In present article introduction section deals with background, statement of the problem and rationale of our study. The main body deals with biological agents of bioterriorism and their targets, history, present scenario of bioterrorism. Finally, awareness and control measures, challenge and prospects of biosecurity in Nepal. The ubiquity of biological equipment, technical knowledge and ease of production has stimulated the threat of bioterrorism. Some of the challenging dimensions are agroterrorism and bioterrorism because the attack is very difficult to detect and has a devastating effect in a short period. The social and environmental consequences of these attacks can be catastrophic. The study revealed that it would be better to pay attention and go for precaution before the occurrence of bioterror. Improving forensic techniques of the national security wing for detecting and disabling biological weapons will assist in rapid detection. The restriction against easy access to potential bioagents, physical protection, border controls, risk policies and strict law enforcement are the major steps for ensuring biosecurity.

Antagonistic and growth-promoting potential of multifarious bacterial endophytes against Fusarium wilt of chickpea

BackgroundChickpea is the most important legume crop in India, and its productivity is significantly lowered due to biotic constraints such as wilt caused by Fusarium oxysporum f. sp. ciceris. Endophytes help plants to thrive better under stress conditions by regulating plant hormones and inducing systemic resistance. The aim of the present study was to identify chickpea root bacterial endophytes having antagonistic ability for the management of the Fusarium wilt.ResultsTwenty endophytic bacterial strains were isolated from the susceptible and resistant chickpea cultivar, amongst which 35% bacterial endophytes gave positive results for siderophore and 15% isolates were HCN producers, whereas 55% showed good growth on ACC-supplemented medium. Based upon 16S rRNA phylogenetic analysis, efficient endophytic bacterial isolates CRBE1, CRBE3 and CRBE7 were identified as Priestia megaterium, Brucella haematophila and Microbacterium paraoxydans, respectively. Bacterial endophyte CRBE7 and CRBE3 showed pronounced antagonistic activity against Fusarium oxysporum f. sp. ciceris under in vitro conditions. Inoculation of chickpea with isolated bacterial endophytes alone and in combination through seed priming resulted in significant biocontrol activity against Fusarium wilt of chickpea under screenhouse conditions. Biopriming of chickpea seeds alone with CRBE3 and as consortium of CRBE3 + CRBE7 upsurged the phenol content in susceptible and resistant chickpea varieties JG 62 and HC 3, which indicated the role of promising endophytes as potential bio-agents under in vivo conditions.ConclusionsChickpea root bacterial endophytes Priestia megaterium (CRBE1), Brucella haematophila (CRBE3) and Microbacterium paraoxydans (CRBE7) exhibiting antagonistic activity could be incorporated in integrated disease management module against Fusarium wilt of chickpea.

Crystal structure of a short-chain dehydrogenase/reductase from Burkholderia phymatum in complex with NAD.

Burkholderia phymatum is an important symbiotic nitrogen-fixing betaproteobacterium. B. phymatum is beneficial, unlike other Burkholderia species, which cause disease or are potential bioagents. Structural genomics studies at the SSGCID include characterization of the structures of short-chain dehydrogenases/reductases (SDRs) from multiple Burkholderia species. The crystal structure of a short-chain dehydrogenase from B. phymatum (BpSDR) was determined in space group C2221 at a resolution of 1.80 Å. BpSDR shares less than 38% sequence identity with any known structure. The monomer is a prototypical SDR with a well conserved cofactor-binding domain despite its low sequence identity. The substrate-binding cavity is unique and offers insights into possible functions and likely inhibitors of the enzymatic functions of BpSDR.

Potential Biocontrol Agents Diversity for Coffee Leaf Rust <i>Hemileiavastatrix </i>from Southwesten Ethiopia

Coffee leaf rust (CLR), caused by Hemileiavastatrixis the main coffee disease, occurring in the main coffee producing countries worldwide. Effective management of CL Rintegrated approch including the development of resistant varieties, cultural management, biocontrol and chemicals. Considering both the potential source of potential bioagents by this ecological niche and the possibility of practical uses as a tool to be deployed against coffee leaf rust. White colourmycoparasitic growth is often observed on H. vastatrixpustules. The common report is a complex of “white colony forming-taxa” which has been promptly labeled as Verticilliumsp., Lecanicilliumsp. or, at a supposedly more precise level, as Verticilliumlecanii. Taxonomic information about such potential biocontrol fungi is lacking in Ethiopia. In order to investigate the identity of mycoparasites of H. vastatrixand to obtain potential biocontrol agents for the pathogen of coffee, a survey of fungicolous associated with coffee leaf rust was conducted at major coffee producing areas of Ethiopia. One hundred and ten different mycoparasite isolates from H. vastatrixpustules have been captured and characterized. The identified isolates belonging to twelve genera: Akanthomyces, Alternaria, Cladosporium, Fusarium, Gonatophragmium, Lecanicillium, Ochroconis, Paraphaeosphaeria, Phoma, Pleurodesmospora, Sarcopodiumand Simplicillium. Biological control of CLR with mycoparasites remains promising possibility for the future. Nevertheless, without firm taxonomic knowledge and the aid of modern tools, the rapid and precise identification of potential biocontrol agents remain a bottleneck. Therefore, morphological and cultural characterization of these mycoparasites should be supported with appropriate molecular tools and the phylogenic tree approach. Although very little is known about mycoparasites, this work provide piece of informationaboutpotential biocontrolagents deserving more attention by plant pathologists and related scientists for exploiting their service in fight against CLR.

Screening of indigenous rhizobacteria as potential biological control against faba bean (Vicia faba L.) gall disease caused by Olpidium viciae

BackgroundEmerged faba bean gall disease attacks the stem and leaves of the plant and results in complete crop losses. This study was initiated to screen multi-trait rhizobacteria for their antagonistic efficacy under in-vitro and in-vivo conditions against Olpidium viciae to control the effect of gall disease on faba bean. Sixty antagonistic isolates were first examined for their morphological, biochemical, and phenotypic traits.ResultsPseudomonas fluorescens AAUPF62, P. aeruginosa AAUS31, Bacillus AAUMF42, and Bacillus AAUAm28 showed greater than 68, 62, 57, and 54% suppression of O. viciae in dual culture, volatile metabolites, culture filtrate assay, and detached leaves experiments, respectively. The in-vivo study revealed that early treatment of the crop with P. aeruginosa AAUS31 reduced severity by 63% (in FB-Obse) and 54% (in FB-26869) faba bean varieties. The co-inoculation of P. fluorescens AAUPF62 and P. aeruginosa AAUS31 significantly enhanced the shoot (P = 0.003; mean = 122 cm) and root (P = 0.018; mean = 94 cm) length, increased shoot dry weight by 8 factors (83 g pot −1), and reduced final disease severity by 92% in FB-Obse variety.ConclusionsThe results revealed that P. fluorescens AAUPF62 and P. aeruginosa AAUS31 strains could be the potential antagonistic agents of gall disease. The use and early treatment of moderately resistant faba bean varieties by co-inoculation of synergistic potential bioagents were recommended.

Efficacy of different entomopathogenic fungal isolates against chilli aphid, Myzus Persicae (Sulz.)

In recent years, microbial control of insect pests is becoming popular as insect pathogens such as bacteria, viruses, fungi and nematodes serve as potential bioagents in pest management. Among the different microbial agents, entomopathogenic fungi (EPF) are gaining importance in pest control. They can be easily mass cultured on artificial media without affecting their virulence at a cheaper cost. They are highly species specific with minimal impact on non-target organisms. The current study aimed to study the efficacy of entomopathogenic fungal isolates against aphid, Myzus Persicae (Sulz.) in chilli. Laboratory and field experiments were conducted to evaluate the pathogenicity of Beauveria bassiana, Metarhizium anisopliae and Lecanicillium lecanii against chilli aphid. From the study it is revealed that B. bassiana @ 108 spores ml-1 were found to be effective and found to be more superior to the other entomopathogenic fungal isolates viz., Metarhizium anisopliae and Lecanicillium lecanii against chilli aphid.

Evaluation of the Biological Control Agent’s Efficiency Against the Causal Agent of Early Blight of Solanum melongena

Eggplant, an important vegetable crop in Iraq, faces yield losses due to early blight disease caused by Alternaria solani. Two antagonistic fungi (Aspergillus niger and Purpureocillium lilacinum) isolated from eggplant rhizosphere were tested in vitro (dual confrontation technique) and in vivo (preventive treatments) as potential bioagents against the most virulent A. solani isolates. A. niger and P. lilacinum at 30% conidia/ml exhibited high inhibitory rate (55.11%) against A. solani mycelial growth. Furthermore, these two antagonistic species when applied preventively at 30% of the stock conidial suspension in vivo, reduced significantly disease severity index (<28.41%). Moreover, A. niger (11.98 units/g of soluble protein) and P. lilacinum (8.11 units/g of soluble protein) enhanced the polyphenol oxidase activity. Based on the results obtained by this study, it appears that A. niger and P. lilacinum could be employed as foliar treatments against A. solani to promote eggplant growth and development and induce plant systemic resistance. To control A. solani, it is encouraged to use natural enemies as components in integrated disease management. Keywords: Alternaria solani, biological control, polyphenol oxidase, Solanum melongena, antagonistic fungi

Protective and Curative Effects of Trichoderma asperelloides Ta41 on Tomato Root Rot Caused by Rhizoctonia solani Rs33

Two molecularly identified tomato isolates, Trichoderma asperelloides Ta41 and Rhizoctonia solani Rs33, were characterized and antagonistically evaluated. The dual culture technique showed that Ta41 had a high antagonistic activity of 83.33%, while a light microscope bioassay demonstrated that the Ta41 isolate over-parasitized the pathogen completely. Under greenhouse conditions, the application of Ta41 was able to promote tomato plant growth and had a significant increase in plant height, root length, and shoot fresh, shoot dry, root fresh, and root dry weight. It also improved chlorophyll content and total phenol content significantly, both in protective and in curative treatments. The protective treatment assay exhibited the lowest disease index (16.00%), while the curative treatment showed a disease index of 33.33%. At 20 days post-inoculation, significant increases in the relative expression levels of four defense-related genes (PR-1, PR-2, PR-3, and CHS) were observed in all Ta41-treated plants when compared with the non-treated plants. Interestingly, the plants treated with Ta41 alone showed the highest expression, with relative transcriptional levels of CHS, PR-3, PR-1, and PR-2 that were, compared with the control, 3.91-, 3.13-, 2.94-, and 2.69-fold higher, respectively, and the protective treatment showed relative transcriptional levels that were 3.50-, 3.63-, 2.39-, and 2.27-fold higher, respectively. Consequently, the ability of Ta41 to promote tomato growth, suppress Rs33 growth, and induce systemic resistance supports the incorporation of Ta41 as a potential bioagent for controlling root rot disease and increasing the productivity of crops, including tomatoes.

Development of marine oligosaccharides for potential wound healing biomaterials engineering

This study aims to investigate the oxidative degradation of chitosan to produce chitooligosaccharides (CHOS) as a potential bioagent for biomaterials engineering. CHOS was produced via microwaved-assisted oxidative degradation of chitosan by using hydrogen peroxide in an acidic aqueous solution. The effects of the H2O2 concentration, reaction time, microwave power, and reaction temperature on the degradation of chitosan were investigated. Following optimization of these parameters, three soluble CHOS fractions CHOS 1 (4-8 kDa), CHOS 2 (3-5 kDa), and CHOS 3 (1-3 kDa) were synthesized and the physicochemical, structural, thermal properties and water solubility were investigated. No significant structure alteration of the initial chitosan was detected by Fourier transform infrared spectroscopy (FTIR), UV–vis, and nuclear magnetic resonance (NMR) analyses, making our microwave-assisted oxidative degradation a valuable method for the production of CHOS. Interestingly, CHOS fractions exhibited improved radical scavenging activities and antibacterial activities compared to the initial chitosan. The half maximal effective concentration (EC50) of the CHOS fractions were found to be in the range of 2.69–0.724 mg/mL significantly lower than the chitosan (7.75, mg/mL). Besides, the CHOS fractions exhibited lower minimum inhibitory concentration (MIC; in the range of 62.5–500 µg/mL) compared to the initial chitosan (>1000 µg/mL). Moreover, the 3T3-Ll fibroblast cells treated with CHOS fractions exhibited more than 95% viability after 48 h of culture. Cell migration and collagen production assays also showed the positive effect of CHOS fractions, particularly CHOS 3. These results indicate that CHOS can be a promising bioactive agent in biomedical applications, in particular for wound healing applications.

Diadegma aegyptiator Shaumer 1966 (Hymenoptera: Ichneumonidae): New Record Parasitoid on the Rib Miner, Scrobipalpa ocellatella Boyd. (Lepidoptera: Gelechiidae) in Egyptian Sugar Beet Fields

The larvae of the rib miner,Scrobipalpa ocellatella Boyd feed on the sugar beet leaves and roots causing huge damage in such a way that the root rot and thus it caused a reduction in the yield of roots and the sugar content in the roots. Parasitoids are the most effective natural enemies for insect biological control. In nature, several parasitoids were observed to be potential bio-agents of serious crop pests. The future of insecticide-less pest management will be driven by a bouquet of parasitoids and predators complimented by entomopathogens. The reduction in insecticide residues in food - sugar beet is a food crop - is desirable for public health. The present study was carried out at the experimental farm of Sakha Agricultural Research Station, Kafr El-Sheikh Governorate-Egypt throughout two successive seasons 2018/2019 and 2019/2020. New parasitoid was recorded from the rib miner pupae. It was identified as Diadegma aegyptiator on S.ocellatella for the first time in Egypt. The Overall of parasitism were 24.52 and 31.03% in the two seasons, respectively. As well as, statistical analysis proved that a highly positive significant correlation coefficient values between S.ocellatella and its parasitoid in two seasons, respectively.These results elucidate that this parasitoid is a promising tool in reducing S.ocellatella populations.

Current strategies and perspectives in detection and control of basal stem rot of oil palm.

The rapid expansion of oil palm (OP) has led to its emergence as a commodity of strategic global importance. Palm oil is used extensively in food and as a precursor for biodiesel. The oil generates export earnings and bolsters the economy of many countries, particularly Indonesia and Malaysia. However, oil palms are prone to basal stem rot (BSR) caused by Ganoderma boninense which is the most threatening disease of OP. The current control measures for BSR management including cultural practices, mechanical and chemical treatment have not proved satisfactory. Alternative control measures to overcome the G. boninense problem are focused on the use of biological control agents and many potential bioagents were identified with little proven practical application. Planting OP varieties resistant to G. boninense could provide the ideal long-term solution to basal stem rot. The total resistance of palms to G. boninense has not yet been reported, and few examples of partial resistances have been observed. Importantly, basidiospores are now recognized as the method by which the disease is spread, and control methods require to be revaluated because of this phenomenon. Many methods developed to prevent the spread of the disease effectively are only tested at nursery levels and are only reported in national journals inhibiting the development of useful techniques globally. The initial procedures employed by the fungus to infect the OP require consideration in terms of the physiology of the growth of the fungus and its possible control. This review assesses critically the progress that has been made in BSR development and management in OP.

Pseudomonas mendocina LYX: A novel aerobic bacterium with advantage of removing nitrate high effectively by assimilation and dissimilation simultaneously

The problem of nitrate accumulation in aerobic tank and total nitrogen excessive discharge in effluent was very common in traditional livestock and poultry farming wastewater treatment systems owing to the lengthy process flow and low process control level. A strain LYX of aerobic bacterium was isolated from the activated sludge of a wastewater treatment system in a pig farm, which could remove nitrate effectively in aerobic tank and was identified Pseudomonas mendocina by 16S rRNA sequencing. Under the condition of nitrate as the sole nitrogen source, this strain removed over 90% of NO3−-N with an initial concentration of 110 mg/L under aerobic conditions within 48 hours. Among them, 37.9% of NO3− -N was assimilated into Bio-N, about 51.9% was reduced to gaseous nitrogen and less than 0.5% of nitrogen was replaced by NO3−-N and NH4+-N, 9.7% NO3−-N remained in the effluent at the end. At the same time, four key genes (napA, nirK, norB and nosZ) related to nitrate nitrogen removal were expressed during the denitrification process of P. mendocina LYX, in which the transcription level of the indicator genes of this aerobic denitrifying bacterium (napA) was the highest. In addition, it was found with the 15N tracer technique that inoculation of this strain on sludge increased the amount of nitrogen loss from 9.26 nmol N/(g·h) to 23.835 nmol N/(g·h). Therefore, P. medocina LYX is a potential bioagent for advanced nitrogen removal by assimilating and reducing nitrate simultaneously in aerobic tanks.

Compatibility of Trichoderma spp. with fungicides and efficiency against Rhizoctonia solani

Laboratory experiment was conducted to test the compatibility of Trichoderma, a potential bio-control agent with commonly recommended fungicides viz; three systemic fungicides carbendazim (50% WP), carboxin (75% WP) and tebuconazole (2% DS) and one contact fungicide copper oxychloride (50% WP) by poison food technique (50,100, 250, 500, 1000 and 1500 ppm). These fungicides were also used to check efficacy against R. solani causing agent of okra damping off. All four potential bioagents showed compatibility with copper oxychloride but Trichoderma sp.-2 also showed highest compatibility as 55.33 per cent inhibition was observed at 1500 ppm followed by Trichoderma sp.-9 in which 64.57 per cent was observed.Carbendazim was found best fungicide as it gave complete inhibition of fungal pathogen even at 250 ppm concentration. Among four fungicides tested in vitro carbendazim was most effective against R. solani but incompatible with bioagents while copper oxychloride was found compatible with bioagents.

Characterization of a novel heterotrophic nitrifying and aerobically denitrifying bacterium, Halomonas sp. Z8, as a potential bioagent for wastewater treatment

Characterization of a novel heterotrophic nitrifying and aerobically denitrifying bacterium, Halomonas sp. Z8, as a potential bioagent for wastewater treatment

Evaluation of bioagents and chemicals for the management of root rot disease of bell pepper

Bell pepper (Capsicum annuum L. var. grossum Sendt.) a member of Solanaceae family, commonly known as “Sweet pepper ” or “Capsicum ” or “Shimla mirch ” has attained a status of high value crop among vegetables in India because of its delicacy and pleasant flavor besides being rich in fatty acids, flavanoids, volatile oil and carotene. Out of total six bioagent tested under in vitro condition, Trichoderma harzianum (SMA-5) and Trichoderma sp. (AF2) were observed as potential bioagents which inhibited the mycelial growth upto 84.7 per cent. Studies on different methods of application of bioagent revealed that drenching was effective in controlling disease (61.1%). In vitro evaluation of fungicides revealed that out of seven fungicides tested, Ridomil MZ and Moximate @ 100 μg/ml were highly fungitoxic as compare to other fungicides. Under pot experiments, Ridomil MZ and Moximate @ 0.25 per cent were found highly effective in managing root rot disease upto 64.7 and 59.0 per cent, respectively. Integrated application of Trichoderma sp. (PF2) with Ridomil MZ (1.75g/l) was found most effective in the management of Phytophthora root rot of bell pepper under polyhouse conditions.

Molecular and morphological characterization of rice phylloplane fungi and determination of the antagonistic activity against rice pathogens

Cladosporium spp. is a cosmopolitan fungal genus. In the literature, it has been reported as a biological agent for controlling several plant diseases, but its mechanism of action has never been clarified. The present study aims to identify Cladosporium spp. based on the DNA phylogeny of nine isolates obtained from the phylloplane of rice and their potential antagonistic activity against the main fungal pathogens that affect rice crop. Nine isolates of Cladosporium spp. were identified based on DNA phylogeny, molecular and morphological characterization, and their antagonistic effects with the rice pathogens C. miyabeanus, M. oryzae, M. albescens and S. oryzae. Four isolates were selected to study lytic enzymes such as β-1,3-glucanase, chitinase and protease, and only one isolate was selected for a conidial germination and appressoria formation assay. The nine isolates were identified as C. cladosporioides, C. tenuissimum and C. subuliforme. Four isolates, identified as C. cladosporioides, inhibited the mycelial growth of rice pathogens such as C1H (68.59%) of S. oryzae, C5 G (74.32%) of C. miyabeanus, C11 G (75.97%) of M. oryzae and C24 G (77.39%) of M. albescens. C24 G showed a high activity of lytic enzymes, was tested against C. miyabeanus and M. oryzae, and inhibited conidial germination and appressorium formation by more than 59.36%. The characterization of C. cladosporioides suggested this species as a potential bioagent for the management of several rice diseases, especially rice blast. This is the first time that a potential biological agent from the genus Cladosporium identified at the species level was isolated from the rice phylloplane, and some of its mechanisms of action were demonstrated, such as increasing lytic enzyme activity against rice pathogens.

ANTAGONISTIC POTENTIAL OF RHIZOSPHERIC BIOCONTROL AGENTS AGAINST SOYBEAN ROOT ROT- WILT DISEASE COMPLEX SYNDROME

Biological control is an environmentally safe alternative technique for management of plant pathogenic fungi. This work aims to identify and characterize potential bioagents prevalent in soybean soil. A total of 27 fungal isolates were recovered from soybean plants exhibiting typical wilt and root rot symptoms. Pathogenicity of each isolate was examined on soybean seedlings, and the most pathogenic isolates, were selected. Those isolates were identified based on their microscopic features as Fusarium oxysporum Schlecht, F. solani Mart and Rhizoctonia solani Kuhn. The identity of each isolate was confirmed by molecular phylogeny based on internal transcribed spacer (ITS) sequence. Additional 31 microorganisms of the population within soybean rhizosphere were isolated and their potential antagonistic ability was characterized in vitro and in vivo. A collection of three fungi, four bacteria, one actinomycete and one yeast isolate showed significant reduction of mycelial growth of the tested fungal pathogens. The same potential bioagents allocate significant decrease in disease severity percentage of wilt-root rot complex disease under greenhouse and open field conditions compared with mycorrhizae and Rhizolex-T. Potential mechanisms by which the bioagents suppressed soybean wilt-root rot complex disease, were addressed. Application with bioagents induced expression of peroxidase, polyphenol oxidase, chitinase, β-1,3-gluctronase, total carbohydrates and total phenols in treated soybeans, which significantly contribute to plant disease resistance. Quality parameters of soybean seeds from bioagent-treated plants showed favorable elevation in total proteins and oils within the seeds.

Heavy metals/metalloids remediation from wastewater using free floating macrophytes of a natural wetland

Abstract Potential bio-agents in context of phyto-technological innovation for removal of heavy metals/metalloids have been tightly linked with amelioration of environmental and human health. The present research investigated the prospective of three wetland plants Pistia stratiotes (water lettuce) Spirodela polyrhiza (a duckweed), and Eichhornia crassipes (water hyacinth) for synchronized multi-metallic removal of six hazardous/non-essential metals (Fe, Cu, Cd, Cr, Zn, Ni) and As (a metalloid) from a Ramsar site of a biodiversity hotspot. Results revealed high removal (>79%) of different metals during 15 days experiment in microcosms. Further, a saturation limit was reached in relation to heavy metals/metalloid removal, and thus it declined after two weeks of phytoremediation experiment in case of water lettuce and water hyacinth (about 8 days saturation limit noticed for duckweed). In the context of phyto-technological efficiency of selected wetland plants, E. crassipes was the most efficient for the removal of selected heavy metals followed by P. stratiotes and S. polyrhiza Significant correlations between metal concentration in remediated water and wetland plants/macrophytes were obtained. Therefore, these wetland plants may be used in devising eco-friendly remediation of hazardous heavy metals from wastewater.