Biological Control Of Diseases Research Articles

Protective role of foliar application of green-synthesized silver nanoparticles against wheat stripe rust disease caused by Puccinia striiformis

Abstract Green-synthesized nanoparticles have a tremendous antimicrobial potential to be used as an alternative to hazardous fungicides. In this study, the green synthesis of silver nanoparticles (AgNPs) was performed by using Moringa oleifera leaf extract as a reducing and stabilizing agent. The synthesized AgNPs were subjected to different characterization techniques. UV-visible spectroscopy confirmed the surface plasmon resonance band in the range of 400–450 nm, and zeta analysis revealed that the synthesized AgNPs ranged 4–30 nm in size. Scanning electron microscopy depicted tiny fused rectangular segments and the crystalline nature of the synthesized AgNPs was confirmed using X-ray diffraction. Energy dispersive X-ray (EDX) detector confirmed the presence of metallic silver ions. Fourier-transform infrared analysis revealed the presence of phenols as main reducing agents in the plant extract. Foliar application of different concentrations (25, 50, 75, and 100 ppm) of AgNPs was applied on wheat plants inoculated with Puccinia striiformis to assess the disease incidence against stripe rust disease. AgNPs at a conc. of 75 ppm were found to be more effective against wheat stripe rust disease. Furthermore, the application of AgNPs enhanced morpho-physiological attributes and reduced nonenzymatic compounds and antioxidant enzymes in wheat. The present study highlights the potential role of the green-synthesized AgNPs as a biological control of yellow rust disease.

Mode of Attack of Microbiological Control Agents against Plant Pathogens for Sustainable Agriculture and Food Security

Plant diseases accounts for huge losses in agriculture. To ensure food security and sustainability, an agricultural yield must be improved to meet the growing world population. Due to growing awareness of the effect of pesticides and herbicides on human health and the environment, an alternative safe method of controlling phytopathogens has become a subject of intense research. Biological control of plant diseases is the use of living organisms to suppress or inhibit plant pathogens. Microbiological control agents (MBCAs) employ microorganisms to protect crops from destruction by phytopathogens through different modes of action. They may act by direct interaction with the pathogens through hyperparasitism. Indirect antagonistic interaction with the pathogen through induction of host resistance and priming is another mode of attack by MBCAs. Competition for nutrients and space is another important indirect mode of attack by which MBCAs suppress the growth of pathogens through nutrient deprivation. The MBCAs can also interact with the plant through secretion of antibiotics or antimicrobial secondary metabolites with inhibitory effect against the pathogens. A clear understanding of the mode of action of MBCAs is vital to achieving a successful biocontrol operation as well as improving the biocontrol process that is devoid of risks to humans and the environment. Such improvement could be achieved through the use of microbial consortia to enhance the stability and efficiency of the biocontrol process. Further studies on aspects of mass production and formulation to produce more effective, stable, safer and cost effective MBCAs are needed.

Populações de insetos-praga: diversidade e similaridade em cultura agrícola

The anthropic actions expressed by conventional-modern agriculture greatly alter the environment, interfering with the balance of natural processes and making its recovery mechanisms precarious. Thus, the interest in the use of microorganisms in agricultural practices has increased significantly in recent years, both in promoting plant growth and in the biological control of plant pests and diseases. The objective of the present work was to identify the insect pest population in the cucumber crop after foliar application of effective microorganisms (EM). The experiment was carried out in a rural family farm located in the city of São Sebastião-AL. Yellow (4) and blue (4) adhesive plates were used in a usable area of ​​128.8 m2. EM was diluted at a concentration of 4.7% and the applied dose was 50 mL/plant. Six collections were carried out, from December 2020 to February 2021. The individuals sampled were screened and identified at the level of class, order, family and when identified as a pest, at the level of gender. A total of 1301 invertebrate individuals of the Insecta and Arachnida classes were collected. Of these, 55.11% were identified as pest insects and 44.8% as visiting arthropods. The taxon that presented the highest relative frequency was the order Diptera (30.6%) followed by the orders Hemiptera (25.4%), Hymenoptera (24%), Coleoptera (13%), Lepidoptera (5.7%), Araneae (0.8%) and Odonata (0.5%). The pests were representatives of the genera Diabrotica spp, Anastrepha spp, Myzus spp, Bemisia spp, Atta spp and Diaphania spp. 24.7% of the visiting arthropods were predators. The arthropod population increase occurred from the 40th day after planting, with growth peak at the 57th day.

Biological control of Fusarium tomato-wilt disease by cyanobacteria Nostoc spp.

This study investigated the effect of foliar application of extract and culture of Nostoc calcicola and Nostoc linckia on the Fusarium oxysporum f. sp. lycopersici (FOL) that infects tomatoes (Solanum lycopersicum) plant in vitro and in vivo. Cyanobacterial isolates were isolated from saline soils at El-Hamoul and Seidy Salem locations Kafr Elsheikh, Egypt, and identified to be N. calcicola and N. linckia Bioactive compounds of extract were analyzed by Gas chromatography-mass spectrometry (GC-MS). Dry weight, carotene, chlorophyll content, and total phenolic compounds of isolates were measured. Plant height, dry weight, fruit number, and fruit weight of tomatoes were estimated. GC/MS analysis showed 49 and 35 bioactive compounds in extracts of N. calcicola and N. linckia, respectively. N. calcicola possesses the highest values of chlorophyll a, carotenoid, and total phenol contents in dry weight compared with N. linckia. After 100days of tomato growth, the results showed the highest yield of tomato fruits with the application of N. calcicola and N. linckia compared with the untreated plants and the plants which were infected with Fusarium, suggesting that N. calcicola and N. linckia can serve as a new bioagent for biological control of the soil fungus Fusarium oxysporum f. sp. lycopersici (FOL).

Screening of Bacillus subtilis HAAS01 and Its Biocontrol Effect on Fusarium wilt in Sweet Potato

Fusarium wilt, a disease caused by Fusarium oxysporum f.sp batatas (Fob) is an important disease in sweet potato production. Using endophytic bacteria for biological control of sweet potato diseases is one of the important ways. A Bacillus subtilis with antagonistic effect on Fusarium wilt of sweet potato was isolated from soil by confrontation culture. According to the biological characteristics, 16S rDNA sequence analysis, and physiological and biochemical analysis, the Bacillus subtilis HAAS01 was named. A pot experiment was conducted for the biological control experiment of strain HAAS01, and the endogenous hormone content, antioxidant enzyme activity, soluble protein content, and related gene expressions of sweet potato plants were detected. The results showed that the HAAS01 strain could promote the production of endogenous hormones and resist the infection of plant diseases together with defensive enzymes and upregulation of related gene expressions. In summary, Bacillus subtilis HAAS01 was effective in controlling Fusarium wilt of sweet potato and has potential for application and development.

Biocontrol efficacy of Bacillus velezensis HC-8 against powdery mildew of honeysuckle caused by Erysiphe lonicerae var. Lonicerae

Powdery mildew caused by Erysiphe lonicerae var. lonicerae is a serious disease that causes significant loss to honeysuckle production in China. This disease is difficult to control by chemical measures, thus biological control may constitute a powerful alternative strategy. To develop an environmentally friendly microbial agent for biocontrol of powdery mildew, we screened strains of Bacillus spp. for biocontrol potential. One of the 102 isolates, strain HC-8, demonstrated high antifungal activity against three phytopathogenic fungi and efficiently suppressed the conidia germination of E. lonicerae under in vitro conditions. This isolate, which offered significant biocontrol of powdery mildew disease in honeysuckle, was identified as belonging to Bacillus velezensis. After challenge inoculation with E. lonicerae, honeysuckle plants treated with a concentration of 1 × 108 CFU/ml showed the highest protection value (PV). Biocontrol efficacy was highest when strain HC-8 was applied prior to pathogen inoculation, and the minimum PV was recorded when HC-8 was used 1 day after pathogen inoculation. Populations of the GFP-tagged strain HC-8-gfp persisted on honeysuckle leaves up to 25 days after spraying. In addition, we found that B. velezensis HC-8 induced defense-related enzyme activities in the leaves of honeysuckle. Thus, the present study provides a potential high-efficiency strategy for the biological control of powdery mildew disease and shows that B. velezensis HC-8 has significant potential as a biocontrol agent for honeysuckle production.

Aureobasidium pullulans S-2 reduced the disease incidence of tomato by influencing the postharvest microbiome during storage

Biological control of postharvest fruit diseases by antagonistic microorganisms is considered an effective alternative to chemical fungicides. The influence of microbial antagonists on the fruit-associated microbiome provides a new perspective for the in-depth study of the antagonistic mechanism. In this study, the biocontrol effect of A. pullulans S-2 against postharvest diseases of tomatoes was investigated. At the same time, the fungal and bacterial microbiota on tomato surfaces were investigated by high-throughput sequencing. The results showed that A. pullulans S-2 could inhibit the decay incidence, maintain fruit firmness and reduce weight loss of tomato. In addition, the treatment group could maintain higher titratable acidity, ascorbic acid and lycopene content than the control group. More dramatic changes in fungal diversity than in bacterial diversity were observed in the microbiota after the application of A. pullulans S-2. Aureobasidium was significantly enriched in the treatment group, while Cladosporium, Mycosphaerella, Alternaria and Penicillium decreased compared to the control group. Pantoea, Brevibacterium, Brachybacterium, Serratia, Glutamicibacter and Pseudomonas also showed significant differences between the two groups. This study shows that the application of A. pullulans S-2 leads to changes in the bacterial and fungal community that can inhibit plant pathogens and reduce the incidence of fruit diseases. It provides new insights into the dynamics of the surface microbiome of tomato after treatment with microbial antagonists.

English

This work aimed to assess in vitro insecticidal and antifungal activities of Mentha rotundifolia and Myrtus communis essential oils against the red flour beetle (Tribolium castaneum) and three fungal species (Botrytis cinerea, Fusarium solani and Colletotrichum acutatum). Oxygenated monoterpenes presented the dominant group with 72.94 and 58.92% respectively for M. rotundifolia and M. communis essential oils. M. rotundifolia and M. communis essential oils composition was dominated by 72.94 and 58.92% of oxygenated monoterpenes, respectively. The determined lethal concentrations of mentha essential oils against T. castaneum adults revealed high toxicity respectively for fumigant and contact tests, LC50 = 0.113 μL cm-2 and LC50 = 32.71 μL L-1 air. However, common myrtle oil showed a weak fumigant activity (LC50 = 357.67 μL L-1 air) and no contact toxicity. Furthermore, M. rotundifolia essential oil showed a marked antifungal toxicity against all the fungal strains. The mycelial growth of the three fungal strains was completely inhibited at the concentrations of 0.33 μL L-1 by contact application and 8, 10 and 12 μL by fumigant application. M. communis essential oil displayed only a contact antifungal toxicity against B. cinerea at the concentration 21.33 μL L-1. Additionally, M. rotundifolia completely inhibited conidial germination of B. cinerea and F. solani, and significantly affected their morphology, with morphological modifications at the rate of 92.94 and 51.11% respectively. In light of in vitro tests results, the mentha essential oil appeared to be an excellent source of antifungal and insecticidal components and will allow the potential development of this species in the biological control of several pests and fungal diseases. © 2021 Friends Science Publishers

Machine learning applied to canopy hyperspectral image data to support biological control of soil-borne fungal diseases in baby leaf vegetables

Baby leaf vegetables constitute a significant segment of the convenience fresh food market. Due to cultivation conditions under plastic tunnels favourable to pathogen and to restrictions about synthetic fungicide applications, these crops are prone to soil-borne diseases and need effective biological management. Real-time tracking by digital means of the performances of antagonistic agents against plant pathogens may be a great opportunity to optimize field practices and increase disease biocontrol efficacy. In this study, a non-linear machine learning approach, based on Artificial Neural Networks technique, was used to assess the biocontrol efficacy of Trichoderma spp. from VIS-NIR spectral reflectance, estimating disease severity in baby leaf young plants during specific plant-pathogen-antagonist interactions. The most successful accurate model architecture achieved a predictive success rate of 74%. The variable impact analysis on the 207 variables considered showed that the 20 most important frequencies lie in the intervals Δω1 = [426,460] nm Δω2 = [495,530] nm Δω3 = [570,667] nm Δω4 = [770,880] nm Δω5 = [940,1000] nm. The model with improved classification accuracy is highly suitable for the automated detection of healthy status considering a wide spectrum of crop/pathogen targets under Trichoderma spp. beneficial dealings. Findings indicate that hyperspectral image-derived features could be used as proxy for disease level tracking under biological control of telluric pathogens in baby leaf vegetable cultivations.

Microbial Consortia for Effective Biocontrol of Root and Foliar Diseases in Tomato.

The use of beneficial microorganisms for the biological control of plant diseases and pests has emerged as a viable alternative to chemical pesticides in agriculture. Traditionally, microbe-based biocontrol strategies for crop protection relied on the application of single microorganisms. However, the design of microbial consortia for improving the reliability of current biological control practices is now a major trend in biotechnology, and it is already being exploited commercially in the context of sustainable agriculture. In the present study, exploiting the microbial library of the biocontrol company Koppert Biological Systems, we designed microbial consortia composed of carefully selected, well-characterized beneficial bacteria and fungi displaying diverse biocontrol modes of action. We compared their ability to control shoot and root pathogens when applied separately or in combination as microbial consortia, and across different application strategies that imply direct microbial antagonism or induced systemic plant resistance. We hypothesized that consortia will be more versatile than the single strains, displaying an extended functionality, as they will be able to control a wider range of plant diseases through diverse mechanisms and application methods. Our results confirmed our hypothesis, revealing that while different individual microorganisms were the most effective in controlling the root pathogen Fusarium oxysporum or the foliar pathogen Botrytis cinerea in tomato, the consortia showed an extended functionality, effectively controlling both pathogens under any of the application schemes, always reaching the same protection levels as the best performing single strains. Our findings illustrate the potential of microbial consortia, composed of carefully selected and compatible beneficial microorganisms, including bacteria and fungi, for the development of stable and versatile biological control products for plant protection against a wider range of diseases.

Endophytic colonization of entomopathogenic fungi increases plant disease resistance by changing the endophytic bacterial community.

Various mechanisms are involved in plant disease resistance mediated by entomopathogenic fungi; however, the role of plant endophytic microbes in disease resistance is unknown. In the present study, we showed that the disease incidence of northern corn leaf blight caused by Exserohilum turcicum (Et) on maize was reduced significantly by soil inoculation with Beauveria bassiana (Bb). Meanwhile, B. bassiana colonization and E. turcicum infection increased the diversity and abundance and diversity of endophytic bacteria and fungi, respectively, while the abundance of endophytic bacterial of the Bb + Et treatment decreased significantly compared with that of Et treatment alone. However, Bb + Et treatment increased the relative abundance of plant beneficial bacteria significantly, for example, Burkholderia and Pseudomonas. Network analyses showed that the microbiome complexity increased after soil inoculation with B. bassiana. Taken together, these results revealed the potential mechanism by which entomopathogenic fungi exert biological control of maize leaf spot disease.

Effects of potassium fulvic acid and potassium humate on microbial biodiversity in bulk soil and rhizosphere soil of Panax ginseng

Potassium fulvic acid (BSFA) and potassium humate (KHM), as organic fertilizers, can improve soil structure, increase soil nutrient levels and prevent plant diseases. However, knowledge is limited regarding how BSFA and KHM influence soil microbial communities and the interrelationships between community members associated with Panax ginseng. Soil pH and nutrient content increased significantly as a result of the addition of BSFA and KHM. The pH, NH4+-N, NO3−-N, AP and AK increased by 1.72 %–5.55 %, 70.09 %–108.39 %, 35.38 %–216.20 %, 1.21 %–14.19 % and 3.40 %–5.94 %, respectively, in the BSFA and KHM treatments. The soil nutrient increase may be related to Micrococcaceae and arbuscular mycorrhizal fungi (AMF). The structure of the microbial community also changed radically from that of the control group, and Chloroflexi (2.69 %–3.15 %), Actinobacteria (4.33 %–7.53 %) and Acidobacteria (9.44 %–11.62 %) were the dominant microorganisms at the phylum level in bacteria. In contrast, the dominant fungi at the phylum level were Ascomycota (77.39 %–78.08 %), Glomeromycota (0.36 %–2.68), Olpidiomycota (0.02 %–3.78 %) and Basidiomycota (0.80 %–1.17 %). Fusarium oxysporum and Ascomycota were biomarkers for BSFA and KHM, which may be related to pathogenic bacteria. Network analysis revealed that the association among members of the soil microbial community was more positive than negative following application of KHM, and more positive (62.5 %) than negative (37.5 %) correlations were observed between bacteria, whereas the fungal community exhibited more positive (97.3 %) than negative (2.7 %) correlations. PICRUST predicted the microbial function of adding KHM and BSFA to the soil, and these pathways mainly belong to the degradation and metabolism of organic matter, saprophytic organisms and plant pathogens. In summary, our study demonstrated that the addition of BSFA and KHM increased the nutrients in the ginseng soil and reshaped the microbial function in soils, providing a theoretical foundation for soil improvement and biological control of ginseng diseases. However, due to the limitations of greenhouse cultivation, additional long-term experiments on farmland with different climate changes are recommended.

Biological Control of Plant Diseases: An Evolutionary and Eco-Economic Consideration.

Biological control is considered as a promising alternative to pesticide and plant resistance to manage plant diseases, but a better understanding of the interaction of its natural and societal functions is necessary for its endorsement. The introduction of biological control agents (BCAs) alters the interaction among plants, pathogens, and environments, leading to biological and physical cascades that influence pathogen fitness, plant health, and ecological function. These interrelationships generate a landscape of tradeoffs among natural and social functions of biological control, and a comprehensive evaluation of its benefits and costs across social and farmer perspectives is required to ensure the sustainable development and deployment of the approach. Consequently, there should be a shift of disease control philosophy from a single concept that only concerns crop productivity to a multifaceted concept concerning crop productivity, ecological function, social acceptability, and economical accessibility. To achieve these goals, attempts should make to develop “green” BCAs used dynamically and synthetically with other disease control approaches in an integrated disease management scheme, and evolutionary biologists should play an increasing role in formulating the strategies. Governments and the public should also play a role in the development and implementation of biological control strategies supporting positive externality.

Biological Control of Plant Diseases in Changing Environment

Excessive pesticide application for plant disease control can result in environmental and health-related problems [...]

Induced systemic resistance (ISR) as a mechanism of biocontrol in maize (Zea mays)

Induced systemic resistance is an alternative mechanism to antagonism for achieving biological control of plant diseases. Induced Systemic Resistance (ISR) involves the activation of latent resistance mechanisms that are expressed upon subsequentsocalled “challenge’ inoculation with a pathogen. Induced resistance occurs naturally as a result of limited infection by the pathogen, particularly when the plant develops a hypersensitive reaction. Therefore, ISR as a mechanism of biocontrol against leaf blight disease (Helminthosporium turcicum) in maize, cv. CO 1 was investigated. The application effect of different formulations of Azospirillum and Paenibacillus cells viz., single strain inoculation, co-inoculation and co-aggregates (natural and artificial) on the enhancement of growth and reduction in leaf blight disease incidence of maize was studied under in vivo conditions. It was observed that the application of each formulation of Azospirillum and Paenibacillus cells augmented the growth parameters and reduction in the incidence of leaf blight disease of maize to a higher level when compared to un-inoculated control. However, the application of Azospirillum and Paenibacillus cells, as, natural co-aggregates, exhibited the highest performance followed by artificial co-aggregates of Azospirillum and Paenibacillus cells co-inoculation and single strain inoculation of PGPR cells. The comparative study of rhizobacterial EPS viz., Azospirillum and Paenibacillus and some ISR inducing chemicals viz., salicylic acid (SA), Jasmonic acid (JA) and Azibenzolar on the enhancement of growth and reduction in leaf blight disease incidence in maize plant revealed incidence to a higher level than rhizobacterial EPS but they couldn't augment the growth of the maize plant as in the case of rhizobacterial EPS. The application of rhizobacterial EPS had both phytostimulatory and biocontrol effect whereas the use of ISR inducing chemicals exert only biocontrol activity against Helminthosporium turcicum.

Current Status and Future Prospects of White Root Rot Management in Pear Orchards: A Review

The current social demand for organic, sustainable, and eco-friendly approaches for farming, while ensuring the health and productivity of crops is increasing rapidly. Biocontrol agents are applied to crops to ensure biological control of plant pathogens. Research on the biological control of white root rot disease caused by a soil-borne pathogen, Rosellinia necatrix, is limited in pears compared to that in apple and avocado. This pathogenic fungus has an extensive host range, and symptoms of this disease include rotting of roots, yellowing and falling of leaves, wilting, and finally tree death. The severity of the disease caused by R. necatrix , makes it the most harmful fungal pathogen infecting the economical fruit tree species, such as pears, and is one of the main limiting factors in pear farming, with devastating effects on plant health and yield. In addition to agronomic and cultural practices, growers use chemical treatments to control the disease. However, rising public concern about environmental pollution and harmful effects of chemicals in humans and animals has facilitated the search for novel and environmentally friendly disease control methods. This review will briefly summarize the current status of biocontrol agents, ecofriendly methods, and possible approaches to control disease in pear orchards.

Evaluation of Trichoderma asperellum B1902 in Controlling Fusarium Wilt of Cavendish Banana Cultivar

Trichoderma species is one of the microorganisms with antagonistic properties as biological control agents. In the banana industry, Fusarium wilt disease caused by Fusarium oxysporum f. sp. cubense (Foc) has been practically managed using chemical pesticides that led to environmental disruptions, ineffective conditions and disease resistance. In preliminary study, T. asperellum gave better result compared to other species in inhibiting the growth of Foc in in vitro condition. Therefore, the aim of this study was to examine the effects of T. asperellum as a biological control of Fusarium wilt disease of banana. A total of 326 fungal isolates were isolated from soil samples obtained around Malaysia and identified as Trichoderma species based on phenotype characteristics. The species identity for the best candidates from dual culture test was confirmed based on internal transcribed spacers (ITS) and translation elongation factor 1 alpha (TEF-1α) sequence identity. In dual culture test, findings showed that three isolates with a high percentage inhibition of radial growth (PIRG) were observed in plates of T. asperellum isolates B1902 (84.85%), T2007 (77.78%) and C1667 (75.76%), which successfully inhibited the growth of F. oxysporum f. sp. cubense isolate 9888. Based on in vivo test, the best candidate was T. asperellum B1902 with lower disease severity index (DSI) value of 0.2 compared to the inoculated control with DSI of 3.6. As a conclusion, T. asperellum B1902 can be used as an alternative treatment in managing Fusarium wilt disease. Hence, future study should be focused on applying T. asperellum as a biocontrol agent in the field and controlling other plant diseases in the agricultural plantation.

Role of Dicer-Dependent RNA Interference in Regulating Mycoparasitic Interactions.

ABSTRACTDicer-like proteins (DCLs) play a vital role in RNA interference (RNAi), by cleaving RNA filament into small RNAs. Although DCL-mediated RNAi can regulate interspecific communication between pathogenic/mutualistic organisms and their hosts, its role in mycoparasitic interactions is yet to be investigated. In this study, we deleted dcl genes in the mycoparasitic fungus Clonostachys rosea and characterize the functions of DCL-dependent RNAi in mycoparasitism. Deletion of dcl2 resulted in a mutant with reduced secondary metabolite production, antagonism toward the plant-pathogenic fungus Botrytis cinerea, and reduced ability to control Fusarium foot rot disease on wheat, caused by Fusarium graminearum. Transcriptome sequencing of the in vitro interaction between the C. rosea Δdcl2 strain and B. cinerea or F. graminearum identified the downregulation of genes coding for transcription factors, membrane transporters, hydrolytic enzymes, and secondary metabolites biosynthesis enzymes putatively involved in antagonistic interactions, in comparison with the C. rosea wild-type interaction. A total of 61 putative novel microRNA-like RNAs (milRNAs) were identified in C. rosea, and 11 were downregulated in the Δdcl2 mutant. In addition to putative endogenous gene targets, these milRNAs were predicted to target B. cinerea and F. graminearum virulence factor genes, which showed an increased expression during interaction with the Δdcl2 mutant incapable of producing the targeting milRNAs. In summary, this study constitutes the first step in elucidating the role of RNAi in mycoparasitic interactions, with important implications for biological control of plant diseases, and poses the base for future studies focusing on the role of cross-species RNAi regulating mycoparasitic interactions.IMPORTANCE Small RNAs mediated RNA interference (RNAi) known to regulate several biological processes. Dicer-like endoribonucleases (DCLs) play a vital role in the RNAi pathway by generating sRNAs. In this study, we investigated a role of DCL-mediated RNAi in interference interactions between mycoparasitic fungus Clonostachys rosea and the two fungal pathogens Botrytis cinerea and Fusarium graminearum (here called mycohosts). We found that the dcl mutants were not able to produce 11 sRNAs predicted to finetune the regulatory network of genes known to be involved in production of hydrolytic enzymes, antifungal compounds, and membrane transporters needed for antagonistic action of C. rosea. We also found C. rosea sRNAs putatively targeting known virulence factors in the mycohosts, indicating RNAi-mediated cross-species communication. Our study expanded the understanding of underlying mechanisms of cross-species communication during interference interactions and poses a base for future works studying the role of DCL-based cross-species RNAi in fungal interactions.

The Influence of Temperature on the Growth, Sporulation, Colonization, and Survival of Trichoderma spp. in Grapevine Pruning Wounds

Trichoderma is a genus of fungi used for the biological control of plant diseases and a large number of its bio-formulates are available in the market. However, its efficacy under field conditions remains unclear, especially for the protection of grapevine plants against Grapevine Trunk Diseases (GTDs). These diseases are caused by a complex of fungal pathogens whose main point of entrance into the affected plants is through pruning wounds. In this research, different Trichoderma native strains have been evaluated according to their ability to grow at different temperatures and their capacity to colonize pruning wounds in adverse climatic conditions. Strains from section Trichoderma have adapted to cooler conditions. On the other hand, strains from clade Harzianum/Virens grow at higher temperatures. However, differences can also be found between strains inside the same clade/section. Native strains were able to colonize more than 70% of vine pruning wounds in winter conditions. The Trichoderma strain T154 showed a significantly higher re-isolation degree from vine plants and its concentration was optimized for spraying onto vine plants. In conclusion, Trichoderma native strains are better adapted to survive in a changing environment, and they could give better protection to grapevine plants in co-evolution with each specific vineyard.

Biological control of damping-off and root rot disease caused by Rhizoctonia solani on cucumber plants

Biological control of damping-off and root rot disease caused by Rhizoctonia solani on cucumber plants