نوع مقاله : مقاله پژوهشی

نویسندگان

• عبدالحسین طاهری ¹
• الهه لطفعلی نژاد ²
• سیدجواد صانعی ¹
• زهرا شهرآبادی ³

¹ گروه گیاه پزشکی، دانشکده تولید گیاهی، دانشگاه علوم کشاورزی و منابع طبیعی گرگان، ایران

² گروه گیاه‌پزشکی، دانشکده تولید گیاهی، دانشگاه علوم کشاورزی و منابع طبیعی گرگان، ایران

³ بخش تحقیقات شرکت دانازیست لوتوس، گرگان، ایران

چکیده

کلیدواژه‌ها

• Trichoderma harzianum
• فرمولاسیون کپسول
• کنترل زیستی
• گلخانه
• ماندگاری solani

عنوان مقاله [English]

Improving the shelf life of encapsulated Trichoderma harzianum as a biocontrol approach against the soil-borne fungus Sclerotinia sclerotiorum under in vitro and greenhouse conditions

نویسندگان [English]

• Abdolhossein Taheri ¹
• Elahe Lotfalinezhad ²
• Seyed Javad Sanei ¹
• Zahra Shahrabadi ³

کلیدواژه‌ها [English]

• Trichoderma harzianum
• Encapsulation
• Biocontrol
• Greenhouse
• shelf life

Extended Abstract

Introduction

In recent decades, advances in crop productivity have largely relied on intensive farming and heavy use of chemical pesticides. However, plant diseases still cause 20–40% yield losses annually, with soilborne fungi representing the most destructive group. Sclerotinia sclerotiorum is one of the most devastating plant pathogens, infecting, more than 500 plant species and persisting in the soil for years through its resistant sclerotia. While fungicides remain widely used, their long-term effectiveness is declining due to pathogen resistance and environmental hazards. As a sustainable alternative, biological control agents—particularly Trichoderma species—have shown great potential through mechanisms such as mycoparasitism, antibiosis, and induction of plant resistance. Nevertheless, their field performance is limited by environmental stresses. To overcome these constraints, encapsulation technology, especially via ionic gelation using biocompatible polymers like sodium alginate, offers an efficient solution by protecting microbial viability, enabling gradual release, enhancing colonization, prolonging shelf life, and reducing application frequency in an environmentally friendly manner.

Materials and Methods

Trichoderma harzianum Ah90 and Sclerotinia sclerotiorum were obtained from the Gorgan University fungal collection. Spore suspension (1.7×10⁷ cfu/ml) was prepared, and encapsulation was performed via ionic gelation using 2% (w/v) sodium alginate and 0.1 M CaCl₂. Capsule size, swelling rate, capsulation efficiency, and spore release kinetics were evaluated. Viability of encapsulated and free spores was tested under different temperatures (5, 25 and 35 °C) and under UV exposure. Capsule biodegradability was measured by weight‑loss assay. In vitro inhibition of S. sclerotiorum was assessed using dual culture, volatile, and non‑volatile compound tests. Greenhouse experiments on tomato (cv. Super Chief) were conducted using encapsulated and non‑encapsulated T. harzianum in pathogen‑infested soil. Disease incidence, plant growth, and polyphenol oxidase activity were measured. Data were analyzed in a factorial CRD with four replications using R. 4.5.1 and Duncan’s test (p ≤ 0.05).

Results

Encapsulated T. harzianum, prepared by ionic gelation method, exhibited approximately spherical. Wet capsules diameters of about 2600 µm and dry diameters of about 1000 µm. Encapsulation efficiency was 99%. Encapsulation also enhanced the survival and stability of T. harzianum at 25°C and 35°C compared to the non-encapsulated form with 5°C being the optimal storage condition for long term. UV exposure for 24 h caused >90% reduction in free spores but far less in dry capsules. No protective difference was observed among dry and wet capsules against temperature changes. Greenhouse experiments confirmed that the encapsulated T. harzianum formulation significantly reduced disease incidence in comparison to non-encapsulated T. harzianum and sodium alginate capsules. The findings substantiate the positive and effective role of encapsulated T. harzianum towards seedling mortality reduction, validating its efficacy as an effective alternative to enhance reduction of chemical pesticide dependency. 

Conclusion

The findings of this study indicate that encapsulation technology markedly enhances the stability and viability of T. harzianum compared to its non‑encapsulated form and can also strengthen its inhibitory potential. Accordingly, the obtained data provide valuable insights into the practical application of encapsulated biocontrol formulations and highlight the promising potential of encapsulated T. harzianum as an effective alternative for reducing dependency on chemical pesticides.

Author Contributions

All authors contributed equally to the conceptualization of the article and writing of the original and subsequent drafts.

Data Availability Statement

The datasets generated or analyzed during the current study are available on request from the authors.

Ethical considerations

All research followed ethical guidelines to minimize harm to insects and avoid disruption of natural habitats. Sampling was limited to the minimum necessary, and no endangered or protected species were collected. All activities complied with relevant regulations, and data were recorded and reported with integrity.

Conflict of interest

The authors declare that there is no conflict of interest regarding the publication of this paper.