Abstract
Durum wheat, one of the most relevant sources of food worldwide, is susceptible to the attack of fungal pathogens responsible for different severe diseases. Specifically, Fusarium Foot Rot (FRR) and Fusarium Crown Rot (FCR) are spread all over the world and the main causal agents belong to Fusarium and Microdochium genera. They can act affecting the roots, the crown and the first internodal portions of the stem base. In addition, this fungal genus is pathogenic also at the spike level, causing Fusarium Head Blight (FHB), responsible for quantitative damage, due to a yield decrease, and qualitative damage due to grain contamination by mycotoxins such as trichothecenes. Nowadays the main management strategies against these diseases are based on agronomic practices and fungicide applications. More sustainable management methods, focused on reducing the use of synthetic agrochemicals to preserve the environment as well as operators’ and consumers’ health, are therefore necessary. Innovative strategies may involve the use of antagonistic microorganisms, applied directly to the plants or to the seed in the form of a coating. In the last years, the research group proposing this project has imple-mented the isolation and selection of microbial strains from different agriculture environments and from the wheat rhizosphere, with the aim to identify possible antagonistic microorganisms to FCR and FHB agents. Preliminary tests performed in vitro based on bacteria belonging to the genera Lactobacillus, Bacillus, Paenibacillus, Pseudomonas and Microbacterium, allowed the identification strains showing promising results in counteracting FCR. However, many gaps in the application of selected strains were identified, spanning from antimicrobial peptides pro-duction, microorganisms’ safety and growth performance to an efficient and economically sus-tainable application of seed coating. Moreover, little is known about endophytic bacteria's ca-pability to counteract FCR and FHB on durum wheat as well as the mycotoxins contaminations in the spike. For these reasons, the final goal of this project is to fill the knowledge gaps to achieve industrial production coupled with a wide-scale application of the select antagonistic strains in the Fusarium diseases management of durum wheat, for a better quality of raw ma-terials, food and for the health of soil, nature and people. Furthermore, the formulation of cul-ture media for the growth of the antagonistic microbial strains valorizing waste and by-products in the agro-food sector will be also developed. The project will be carried out by two Research Units (RUs) belonging to the University of Bologna (UNIBO) and the University of Pe-rugia (UNIPG), both with consolidated experience in the microbial characterization, microorgan-isms manipulation and management of FCR and FHB of durum wheat. Abstract Durum wheat, one of the most relevant sources of food worldwide, is susceptible to the attack of fungal pathogens responsible for different severe diseases. Specifically, Fusarium Foot Rot (FRR) and Fusarium Crown Rot (FCR) are spread all over the world and the main causal agents belong to Fusarium and Microdochium genera. They can act affecting the roots, the crown and the first internodal portions of the stem base. In addition, this fungal genus is pathogenic also at the spike level, causing Fusarium Head Blight (FHB), responsible for quantitative damage, due to a yield decrease, and qualitative damage due to grain contamination by mycotoxins such as trichothecenes. Nowadays the main management strategies against these diseases are based on agronomic practices and fungicide applications. More sustainable management methods, focused on reducing the use of synthetic agrochemicals to preserve the environment as well as operators’ and consumers’ health, are therefore necessary. Innovative strategies may involve the use of antagonistic microorganisms, applied directly to the plants or to the seed in the form of a coating. In the last years, the research group proposing this project has imple-mented the isolation and selection of microbial strains from different agriculture environments and from the wheat rhizosphere, with the aim to identify possible antagonistic microorganisms to FCR and FHB agents. Preliminary tests performed in vitro based on bacteria belonging to the genera Lactoplatibacillus, Bacillus, Paenibacillus, Pseudomonas and Microbacterium, allowed the identification strains showing promising results in counteracting FCR. However, many gaps in the application of selected strains were identified, spanning from antimicrobial peptides pro-duction, microorganisms’ safety and growth performance to an efficient and economically sus-tainable application of seed coating. Moreover, little is known about endophytic bacteria's capability to counteract FCR and FHB on durum wheat as well as the mycotoxins contaminations in the spike. For these reasons, the final goal of this project is to fill the knowledge gaps to achieve industrial production coupled with a widescale application of the select antagonistic strains in the Fusarium diseases management of durum wheat, for a better quality of raw materials, food and for the health of soil, nature and people. Furthermore, the formulation of culture media for the growth of the antagonistic microbial strains valorizing waste and by-products in the agro-food sector will be also developed. The project will be carried out by two Research Units (RUs) belonging to the University of Bologna (UNIBO) and the University of Perugia (UNIPG), both with consolidated experience in the microbial characterization, microorgan-isms manipulation and management of FCR and FHB of durum wheat.
Results achieved
Effectiveness of seed biopriming treatments in the management of FRR and FCR in durum wheat. The main results of the project highlighted the effectiveness of seed biopriming treatments in the management of FRR and FCR in durum wheat. Following a preliminary screening, four bacterial strains were identified as the most promising candidates: two strains belonging to Bacillus amyloliquefaciens (MA8 and CAAd) and two Lactiplantibacillus plantarum strains (HB23 and 5H1). The efficacy of these treatments was evaluated through in vivo seed biopriming experiments conducted under controlled conditions, using Fusarium culmorum (strain Fc1126) and F. graminearum (strain Fg566), two widespread and highly aggressive pathogens of durum wheat. Plant responses were assessed 21 days after inoculation by measuring germination percentage and disease severity through an infection index. In inoculated controls, fungal infection caused typical symptoms of FRR and FCR, including stem thinning, extensive basal necrosis, and, in the most severe cases, seedling collapse. In contrast, no symptoms attributable to FRR or FCR were observed in non-inoculated controls. In both F. culmorum and F. graminearum inoculation assays, treatments based on bacterial strains maintained high germination percentages and were statistically comparable to the chemical control at 21 days post-inoculation. Conversely, reduced germination was observed in seeds treated with the experimental biological product based on essential oils and low copper content, suggesting a possible phytotoxic effect during early developmental stages. Clear differences among treatments emerged from the analysis of the infection index. The chemical control showed the lowest disease severity in both assays, whereas inoculated controls exhibited high levels of infection. Treatments with the two B. amyloliquefaciens strains resulted in only limited reductions in disease severity, with relatively high infection index values. In contrast, treatments with the two lactic acid bacteria strains led to a significant reduction in disease severity against both pathogens. In particular, strain HB23 proved to be the most effective biological treatment, reducing disease severity by 44.4% against F. culmorum and by 49.2% against F. graminearum. Strain 5H1 also showed significant, though lower, efficacy, with reductions of 24.7% and 31.5% against F. culmorum and F. graminearum, respectively. Overall, these results demonstrate that specific bacterial strains, especially the strain HB23, are able to significantly reduce the severity of FRR and FCR without negatively affecting seed germination. This confirms the strong potential of seed biopriming as a sustainable biological strategy for the management of Fusarium root and crown rot in durum wheat. Effectiveness of bacterial spike treatments for the management of FHB in durum wheat. Preliminary screenings in controlled environments and in open field conditions (the latter conducted at the experimental station of the University of Perugia, Department of Agricultural, Food and Environmental Sciences, Agronomy and Herbaceous Crops Research Unit, located in Papiano, Perugia, Umbria) allowed the selection of ten bacterial strains with the highest efficacy and the optimal starter solution (10 mM MgCl₂ + 5 g/L glucose) to promote bacterial colonization of durum wheat spikes. Subsequently, the selected bacterial strains were compared with a reference chemical and microbiological commercial product in a controlled-environment trial on durum wheat (cv. San Carlo). The bacterial suspensions (2.5 × 10⁷ CFU/mL), applied with the starter solution at the BBCH65 stage (full flowering), were followed, after 24 hours, by inoculation with a DON producing F. culmorum strain (FC74) (2.5 × 10⁵ conidia/mL). The efficacy of the bacterial strains in counteracting the pathogen was assessed through symptom evaluation and quantification of the pathogen’s DNA. The same experiment was conducted in small-scale field trials (carried out at the aforementioned experimental station), where, in addition to the previous parameters, DON levels (ELISA test) and grain yield were also measured. In the controlled-environment experiDettagli del progetto
Responsabile scientifico: Antonio Prodi
Strutture Unibo coinvolte:
Dipartimento di Scienze e Tecnologie Agro-Alimentari
Coordinatore:
ALMA MATER STUDIORUM - Università di Bologna(Italy)
Contributo totale di progetto: Euro (EUR) 224.750,00
Contributo totale Unibo: Euro (EUR) 123.750,00
Durata del progetto in mesi: 24
Data di inizio
30/11/2023
Data di fine:
30/11/2025
