Production of Trichoderma harzianum K179 bioagent for maize diseases control: complete laboratory stage bioprocess development.

AIMS: In order to be competitive on the market, the production of biopreparations needs to be optimized, modelled, and assessed in the early stages of its development. The aim of this paper was to optimize medium for the production of Trichoderma harzianum K179 biocontrol agent, to analyze its kinetics at enlarged laboratory scale and finally economic analysis of the production of this high-value product through simulation modelling. METHODS AND RESULTS: The results showed that the bioprocess of T. harzianum K179 bioagent production in a laboratory bioreactor on the medium with optimal composition (dextrose 10 g l-1, soy flour 6.87 g l-1, K2HPO4 1.51 g l-1, KCl 0.5 g l-1, and MgSO4 × 7H2O 0.5 g l-1), at stirring speed of 1.75 × g and aeration intensity of 1.5 vvm, can be shortened from 96 to 36 h. The results of bioprocess economic analysis showed that with a 25-year project lifetime and an investment payback time of 7.58 years, this project represents an economically viable system. CONCLUSIONS: Complete analysis of the bioprocess of T. harzianum K179 biocontrol agent production showed that the biologically produced preparation can be competitive on the market with synthetic preparations.

Strategy of Nematophagous Fungi in Determining the Activity of Plant Parasitic Nematodes and Their Prospective Role in Sustainable Agriculture.

In this review, we supply a framework for the importance of nematophagous fungi (nematophagous fungi [NF]) and their role in agricultural ecosystems. We characterize the taxonomy, diversity, ecology, and type of NF, depending on their interaction with plant-parasitic nematodes (PPNs). We described potential mechanisms of NF in the control of PPNs, the efficiency and methods of utilization, and the use of nematicides in sustainable agriculture. We explain the utilization of NF in nanotechnology as a new approach. NF are significant in the soil for having the effective potential for use in sustainable agriculture. These types of fungi belong to wide taxa groups, such as Ascomycota, Basidiomycota, and other groups. Diverse NF are available in different kinds of soil, especially in soils that contain high densities of nematodes. There is a relationship between the environment of nematodes and NF. NF can be divided into two types according to the mechanisms that affect nematodes. These types are divided into direct or indirect effects. The direct effects include the following: ectoparasites, endoparasites, cyst, or egg parasites producing toxins, and attack tools as special devices. However, the indirect effect comprises two groups: paralyzing toxins and the effect on the life cycle of nematodes. We explained the molecular mechanisms for determining the suitable conditions in brief and clarified the potential for increasing the efficacy of NF to highly impact sustainable agriculture in two ways: directly and indirectly.

A Combined Use of Rhizobacteria and Moringa Leaf Extract Mitigates the Adverse Effects of Drought Stress in Wheat (Triticum aestivum L.).

Less nutrient availability and drought stress are some serious concerns of agriculture. Both biotic and abiotic stress factors have the potential to limit crop productivity. However, several organic extracts obtained from moringa leaves may induce immunity in plants under nutritional and drought stress for increasing their survival. Additionally, some rhizobacterial strains have the ability to enhance root growth for better nutrient and water uptake in stress conditions. To cover the knowledge gap on the interactive effects of beneficial rhizobacteria and moringa leaf extracts (MLEs), this study was conducted. The aim of this experimental study was to investigate the effectiveness of sole and combined use of rhizobacteria and MLEs against nutritional and drought stress in wheat. Nitrogen-fixing bacteria Pseudomonas aeruginosa (Pa) (108 CFU ml-1) was inoculated to wheat plants with and without foliar-applied MLEs at two different concentrations (MLE 1 = 1:15 v/v and MLE 2 = 1:30 v/v) twice at 25 and 35 days after seed sowing (50 ml per plant) after the establishment of drought stress. Results revealed that Pa + MLE 2 significantly increased fresh weight (FW), dry weight (DW), lengths of roots and shoot and photosynthetic contents of wheat. A significant enhancement in total soluble sugars, total soluble proteins, calcium, potassium, phosphate, and nitrate contents validated the efficacious effect of Pa + MLE 2 over control-treated plants. Significant decrease in sodium, proline, glycine betaine, electrolyte leakage, malondialdehyde, hydrogen peroxide, superoxide dismutase (SOD), and peroxide (POD) concentrations in wheat cultivated under drought stress conditions also represents the imperative role of Pa + MLE 2 over control. In conclusion, Pa + MLE 2 can alleviate nutritional stress and drought effects in wheat. More research in this field is required to proclaim Pa + MLE 2 as the most effective amendment against drought stress in distinct agroecological zones, different soil types, and contrasting wheat cultivars worldwide.

The Possible Biotechnological Use of Edible Mushroom Bioproducts for Controlling Plant and Animal Parasitic Nematodes.

The present paper reviewed publications on the nematocidal activity of edible mushrooms (EM) and their potential use as sustainable tools for the control of parasitic nematodes affecting agriculture and livestock industry. Nematodes are organisms living in the soil and animals' guts where they may live as parasites severely affecting economically important crops and farm animals, thus causing economic losses to worldwide agriculture. Traditionally, parasitic nematodes have been controlled using commercial pesticides and anthelmintic (AH) drugs. Over the years, nematodes developed resistance to the AH drugs, reducing the usefulness of many commercial drugs. Also, the use of pesticides/anthelmintic drugs to control nematodes can have important negative impacts on the environment. Different EM have been not only used as food but also studied as alternative methods for controlling several diseases including parasitic nematodes. The present paper reviewed publications from the last decades about the nematocidal activity of EM and assessed their potential use as sustainable tools for the control of nematodes affecting agriculture and livestock industry. A reduced number of reports on the effect of EM against nematodes were found, and an even smaller number of reports regarding the potential AH activity of chemical compounds isolated from EM products were found. However, those studies have produced promising results that certainly deserve further investigation. It is concluded that EM, their fractions and extracts, and some compounds contained in them may have biotechnological application for the control of animal and plant parasitic nematodes.

Identification and Production of Beauvericin by Fusarium subglutinansand F. sacchari from Sugarcane

Abstract Fusarium is producing several important mycotoxins including beauvericin (BEA). Two species of Fusarium viz. F. subglutinans and F. sacchari cause the Pokkahboeng disease of sugarcane. The studies on the occurrence and toxicity of BEA are scarce. Therefore, this study aimed to identify the isolates of Fusarium and detect their ability to produce BEA. The toxicity of BEA was also tested on brine shrimp Artemia salina. Many isolates of Fusarium were isolated from the infected plants of sugarcane in Malaysia. We identified the species of Fusarium according to their morphological characteristics. The capability of Fusarium isolates for producing the BEA was estimated by using a thin layer chromatography. The toxicity bioassay of BEA was conducted on the brine shrimp larvae. The results were identified on F. subglutinans and F. sacchari in 55 isolates of Fusarium. All isolates demonstrated the ability to produce BEA. Interestingly, BEA exhibited variation in toxicity between low toxic to very higher toxicity 100%. F. subglutinans and F. sacchari were able to produce BEA and possibly BEA may be causing toxicity in the host tissue and may be acting as a potential pathogenicity factor. Therefore, we consider BEA as an interesting factor in determining the virulence of fusarium isolate.