Epsilon Archive for Student Projects

Abstract

This study investigated the effects of touch stimulation on insect behaviour, volatile emissions and gene expression in cotton (Gossypium hirsutum), focusing on the implications for plant defences. Furthermore, the potential priming effects of touch on enhancing defence induction was explored. Using an 8-day touch treatment on young cotton plants, followed by herbivore damage, I observed notable insect behavioural responses; Spodoptera littoralis females exhibited a preference for ovipositing on touch-treated plants, while male mate-seeking was less affected. Analysis of volatile organic compound (VOC) emissions revealed subtle shifts in response to touch. Although the total volatile profiles of touch-treated plants were only slightly affected by touch, the abundance of specific compounds, such as (E)-4,8-dimethyl-1,3,7-nonatriene and nonanal, were increased. While direct activation of volatile plant defences by touch could not be discerned, it is possible that touch affects other defence modalities within the plant, or serve as a signaling cue for the coordination of defence induction in neighbouring plants. Additionally, the study provides preliminary insights into the effect of touch on gene expression profiles. In summary, this study contributes to the understanding of touch stimuli in plant-insect interactions, highlighting the need for additional research into touch-responsive cotton genes to further unravel plant defence mechanisms.