Effect of 42 amino acid long amyloid-β peptides on Arabidopsis plants

Although the evolution of Arabidopsis thaliana and humans diverged approximately 1.6 billion years ago, recent studies have demonstrated that protein function and cellular processes involved in disease response remain remarkably conserved. Particularly, γ-secretase, a multisubunit protein complex that participates in intramembrane proteolysis (RIP) regulation, is also known to mediate the cleavage of more than 80 substrates including the amyloid precursor protein (APP) and the Notch receptor. Although the genes (PS1/2, APH-1, PEN-2, and NCT) coding for the γ-secretase complex components are present in plant genomes, their function remains largely uncharacterized . Given that the deposition of 42 amino acid long amyloid-β peptides (hAβ42) is thought to be one of the main causes of Alzheimer's disease, we aimed to examine the physiological effects of hAβ42 peptides on plants. Interestingly, we found that Arabidopsis protoplast death increased after 24 h of exposure to 3 or 5 μM hAβ42 peptides. Furthermore, transgenic Arabidopsis plants overexpressing the hAβ42 gene exhibited changes in primary root length and silique phyllotaxy . Taken together, our results demonstrate that hA β42 peptides, a metazoan protein, significantly affect Arabidopsis protoplast viability and plant morphology.