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Sajjad Reyhani Haghighi

Candidature

PhD Candidate

Thesis Title

The Impacts of Warming, Heatwaves, and UVB Radiation on Plant Silicon Defences against Herbivores

Research Project

Sajjad Reyhani HaghighiMy research examines how silicon (Si) accumulation in grasses enhances plant defence against herbivory under intensifying climatic conditions—particularly elevated ultraviolet (UV) radiation and heatwaves. Climate models project that these stressors will become more frequent and severe globally, posing serious challenges to agriculture. In Australia, for example, average temperatures have risen by 1.47°C (± 0.24°C) since 1910, with extreme heat days more than tripling in recent decades (IPCC Sixth Assessment Report, 2021). This warming trend, coupled with a 4% decrease in ozone layer thickness since the 1980s, has significantly increased harmful UV levels—potentially reducing crop yields by up to 20%.

Silicon deposited in and around specialized leaf cells toughens leaf tissues, causing abrasive damage to insect mouthparts, reducing feeding efficiency, and mitigating crop losses. Beyond structural defences, recent evidence suggests silicon may also influence signalling pathways and secondary metabolites, which help plants cope with UV-related damage and heat stress—factors that in turn affect insect performance and fitness.

In this project, I explore plant-insect interactions under these climatic challenges, investigating how silicon supplementation influences plant and subsequently insect responses via physiological, biochemical, and molecular analyses. By integrating multiple levels of study—from field and glasshouse experiments to controlled-environment chambers—this research aims to deepen our understanding of how silicon mediates plant-herbivore dynamics under climate change. Ultimately, these findings could inform more sustainable, resilient agricultural practices in Australia and beyond.

You can find more about my research and related updates on Google Scholar, ResearchGate and LinkedIn.

Honors and Awards

  • Genetics Society of Australasia (GSA) Student Grant Scheme, Ramaciotti Centre for Genomics Illumina Award (valued at over $15,000), November 2024
  • Australian Government Research Training Program (RTP) Postgraduate Research Scholarship Award and Fee Waiver, October 2022.

Publications

Pasandideh Saqalaksari, M., Asghar Talebi, A., van de Kamp, T., Reyhani Haghighi, S., Zimmermann, D., Richter, A. (2024). EntomonVR: a New Virtual Reality Game for Learning Insect Morphology. Journal of Insect Biodiversity and Systematics. https://doi.org/10.61186/jibs.10.3.557

Reyhani Haghighi, S., Pasandideh Saqalaksari, M., Johnson S. (2023). Artificial Intelligence in Ecology: A Commentary on a Chatbot's Perspective. The Bulletin of the Ecological Society of America. https://doi.org/10.1002/bes2.2097

Homayoonzade, M., Reyhani Haghighi, S., Hosseininaveh, V., Talebi, Kh., Roessner, U. & Winters, A. (2022). Effect of spirotetramat application on salicylic acid, antioxidative enzymes, amino acids, mineral elements, and soluble carbohydrates in cucumber (Cucumis sativus L.). Biology and Life Science Forum, 11(1), 3. https://doi.org/10.3390/IECPS2021-11921

Reyhani Haghighi, S., Hosseininaveh, V., Maali-Amiri, R., Talebi, K., & Stelinski L. (2021). The salicylic acid induced resistance to the drought-stressed pistachio seedlings influences the physiological performance of Agonoscena pistaciae (Hemiptera: Aphalaridae). Journal of Economic Entomology, 114(5):2172–2188. https://doi.org/10.1093/jee/toab149

Reyhani Haghighi, S., Hosseininaveh, V., Maali-Amiri, R., Talebi, K., & Irani, S. (2021). Improving the drought tolerance in Pistachio (Pistacia vera) seedlings by foliar application of salicylic acid. Gesunde Pflanzen, 73:495-507. https://doi.org/10.1007/s10343-021-00569-z

Homayoonzadeh, M., Hosseininaveh, V., Reyhani Haghighi, S., Talebi, K., Roessner, U., & Maali-Amiri, R. (2021). Evaluation of physiological and biochemical responses of pistachio plants (Pistacia vera L.) exposed to pesticides. Ecotoxicology, 30:1084–1097. https://doi.org/10.1007/s10646-021-02434-1

Supervisory Panel

Professor Scott N. Johnson, A/Professor Chris Cazzoneli, Professor Sue Hartley (The University of Sheffield)