Deciphering how mechanical stress can prime plant defence mechanisms and train a hardier crop plant
Discovering How Mechanical Stress Regulate Phytohormones and Apocarotenoids to Prime Resistance against Insect Herbivory and Train Epigenetic Memory
Plants acclimate to short or prolonged periods of biotic and abiotic stress by changing their phenotype, altering phytohormones, metabolite signalling pathways and gene expression. Mechanical Stress (MS) is one ubiquitous environmental factor that regulates plant growth and development. Examples of MS stimulations experienced by plants in nature include touch or rubbing between plant organs, physical perturbation by wind, sound vibrations by herbivore chewing, and heavy rainfall. Repetitive MS can alter plant architecture (a process called-thigmomorphogenesis); activates physiological and biochemical processes; and facilitate defence against other abiotic or biotic stresses.
Herbivorous insects cause biotic stress challenging plant growth, physiology, and biochemistry. Plant responses to herbivore feeding involved with the production of broad ranged inhibitory proteins, phytohormones (e.g. Jasmonic acid) and their signal transduction cascades. There are other plant metabolites induced upon insect feeding that serve to induce secondary defence mechanisms. Carotenoids and specialised cleavage products (e.g. apocarotenoids) are essential group of organic molecules that serve as precursor substrates to produce phytohormones and defence during plant-insect interactions.
Repetitive MS and herbivory can mediate phenotypic variation by altering plant traits, an acclimation response that can be conferred to offspring in the next generation indicating that MS may induce some sort of cellular or epigenetic memory formation and promote thigmomophogenesis.
My PhD thesis aims are to; 1) elucidate if MS can induce carotenoid and apocarotenoid accumulation in leaves independent of MS-induced phytohormone signalling pathways; 2) determine the mechanism by which herbivory induces apocarotenoid levels in leaves to promote resistance against herbivory; and 3) verify if MS can induce epigenetic memory formation during juvenile plant development. The outcome of my PhD research will guide MS as a tool to improve field-crop pest resistance, thus ensure sustainable horticulture crop production under extreme climatic events.
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- Western Sydney University (WSU) Postgraduate Research Scholarship for PhD Research at Hawkesbury Institute for the Environment, WSU, Richmond 2753, NSW, Australia.
- ERUSMUS MUNDUS Master of Science Scholarship in Sustainable Development in Agriculture; University of Copenhagen, Denmark
Brenya E, Pervin M, Chen Z, Tissue D, Johnson SN, Braam J, Cazzonelli CI, (2022) 'Mechanical stress acclimation in plants: Linking hormones and somatic memory to thigmomorphogenesis', Plant Cell and Environment, nol.45, no.4, pp 989-1010
Dr. Christopher Cazzonelli, Ass. Prof. Scott Johnson