Comprehensive characterization of Cry9 insecticidal toxins – a vital insight into Bacillus thuringiensis biology and a key to progress in biological pest control

Description

Discipline: Biological sciences

For centuries, agriculture has been engaged in an uneven battle against larvae of insects from the order Lepidoptera — voracious caterpillars that represent one of the most destructive threats to global crop production. Although synthetic pesticides have become a common crop protection tool, their use entails serious consequences: from high economic costs, health risks to humans, to environmental degradation and a dramatic decline in beneficial organisms, including key ecosystem pollinators.

Protein-based bioinsecticides produced by the entomopathogenic bacterium Bacillus thuringiensis have revolutionized plant protection, offering a highly selective and eco-friendly alternative to chemical insecticides. The toxins of this bacterium, especially the Cry protein family, exhibit strong insecticidal activity against Lepidoptera pests while remaining safe for humans and the environment. Unfortunately, intensive and long-term use of Bt bioinsecticides based on Cry1 and Cry2 toxins has led to increasing resistance in target insect populations. This alarming phenomenon may significantly reduce the effectiveness of this groundbreaking technology and create a serious gap in biological pest control systems—especially in the context of sustainable global agriculture challenges.

Where then should we look for future solutions? The key may lie where it all began—in the vast genetic diversity of B. thuringiensis strains, containing a genetically rich yet still only marginally explored pool of insecticidal proteins. Currently, proteins from the Cry9 family are at the center of attention—a mysterious but highly promising class of toxins with unique structural features and potentially broad-spectrum activity, including efficacy against strains resistant to classical Cry toxins.

Although sequences of 15 different Cry9 toxins are already known, our understanding of their biological functions remains incomplete—particularly compared to the extensively studied Cry1 and Cry2 proteins. Meanwhile, our latest research indicates exceptional activity of one Cry9 toxin against economically important Lepidoptera species, suggesting untapped entomopathogenic potential. Preliminary phylogenetic analysis further reveals a surprising domain architecture in Cry9 proteins, indicating significant evolutionary diversity. Targeted exploration of this toxin group may lead to breakthroughs in biological pest control strategies.

This project aims to conduct comprehensive research on Cry9 pesticidal proteins, including:

• Expression, purification, and thorough molecular characterization of Cry9 toxins,
• Determination of Cry9 toxin activity against Lepidoptera insects and other invertebrate groups,
• Structural-functional analyses of the proteins to elucidate the basis of their specificity.

The studies will advance our knowledge of the molecular and insecticidal properties of Cry9 toxins, substantially enriching our understanding of B. thuringiensis biology and its diverse entomopathogenic mechanisms. Detailed characterization of these fascinating proteins will uncover their evolutionary adaptations, structure-function relationships, and unique modes of action, providing key insights into toxin-invertebrate interactions. This in-depth investigation of Cry9 toxins, along with assessment of their biological activity, will lay the groundwork for using these proteins as a new generation of bioinsecticides and developing novel crop protection strategies in agriculture, horticulture, and forestry. It promises more sustainable and effective solutions while reducing dependence on chemical pesticides.

Principal investigator: dr hab. Jakub Baranek NCN 2024/55/B/NZ9/01386

Recruitment:

Selection Committeee

Schedule of  the Doctoral  School enrolment procedure: 

Recruitment fee

The recruitment fee is 75 EUR.

Form of the selection procedure

One-stage procedure.

Language of the selection procedure, including interviews:

Polish or English language. 

Required documents:

Candidates applying based on exceptional academic achievements must include a scan of the following:  

1) For first-cycle graduates: the diploma and supplement. 

2) For students completing the third year of a unified master’s programme: a certificate indicating their academic average from years 1 to 3, along with a transcript. 

Candidates educated outside Poland must additionally submit: 

1) A scanned copy of their higher education diploma and supplement for both first- and second-degree qualifications (Bachelor’s and Master’s), in the original language and a certified translation into English or Polish.

2) A scanned copy of their passport (for foreign applicants). 

 Evaluation criteria

 1. A minimum grade of "very good" or equivalent from a second-cycle (master’s) or unified master’s degree diploma (5 points). Candidates applying on the basis of exceptional scientific achievements (e.g., grant awarded under the “Pearls of Science” competition) will also receive 5 points. 

2. Evaluation of up to three documented scientific achievements submitted during registration in the IRK system, assessed according to the detailed criteria of the candidate's accomplishments (maximum of 20 points). 

3. Assessment of other documented activities, based on up to three achievements indicated by the candidate, as per the specific criteria for the discipline (maximum of 5 points). 

4. The outcome of the interview, which assesses: 

a) The candidate’s knowledge and competencies relevant to their intended research, including discipline-specific expertise. 

b) Research methodology appropriate to the chosen discipline. The interview has a maximum duration of 30 minutes and awards up to 50 points. 

5. Evaluation of the research project prepared for admission, or in the case of recruitment tied to a grant project, the author’s concept for implementing the project (maximum of 20 points). Assessment focuses on: 

a) Formulation of the research objective and presentation of the research problem. Page 6 of 9 

b) Originality of the research idea and approach to solving the research problem. 

c) Methodology suited to the indicated discipline. 

d) Awareness of the current state of research, supported by a basic bibliography. 

e) The project’s significance for the development of the chosen discipline. 

Condition of admission to the Doctoral School 

Education Program

Education at the doctoral school lasts 8 semesters. Education at the Doctoral School  is offered on the basis of a framework curriculum and an individual research plan and ends with the submission of a doctoral dissertation.

The framework curriculum at the doctoral school includes a catalogue of modules of compulsory classes, elective compulsory classes and optional classes. It also:

1)    defines their schedule

2)    defines the way in which the classes are taught

3)    defines how learning outcomes are verified.

Education begins on 1st October, 2025.

Supervisors

A doctoral student works under the supervision of a supervisor or supervisors, or a supervisor and auxiliary supervisor, who will be appointed by the Deputy Rector at the request of a doctoral student (within 3 months of the start of his or her studies at the Doctoral School).

Scholarships

The doctoral scholarship amounts to PLN 5000 (gross-gross) per month before the mid-term evaluation and PLN 6500 (gross-gross) per month after the mid-term evaluation.

Rules of admission to doctoral schools of Adam Mickiewicz University, Poznań in the academic year 2025/2026, Appendix to Resolution No. 46/2024/2025 of UAM Senate of 27 January, 2025.