5) Mr. Anmol Mishra

Plants have evolved multiple defense strategies to resist or avoid insect damage, including the production of toxic chemical compounds, the formation of physical barriers, and metabolic adjustments through the reallocation of essential compounds. As plants progress through their growth phases, the allocation of resources between development and defense may shift, leading to variations in defense responses at different developmental stages. However, the impact of these defense strategies on different developmental stages has not been fully explored. To understand the dynamic trade-off between growth and defense, the monocot plant Setaria viridis was infested with Rhopalosiphum padi aphids, one of the most economically significant pests, known for causing substantial crop yield losses. We conducted a transcriptome analysis of plants from 4-week-old young seedlings (vegetative stage) to 7-week-old seedlings (reproductive stage), following infestation with aphids. We identified the induction of both serotonin and phenylpropanoid pathway-related genes between the 4th and 7th weeks. These pathways are crucial for synthesizing various secondary metabolites that aid in plant defense against herbivory. Total chlorophyll content was reduced in the 3rd and 4th weeks; however, downregulation of photosynthesis-related genes was observed in all weeks. Moreover, S. viridis showed significant induction of trichomes, limited to the 3rd to 5th weeks, in response to aphid infestation. The findings of this study deepen our understanding of how plants respond to herbivory at different developmental stages, revealing which growth phases are more vulnerable to insect infestation due to weaker defense mechanisms. This knowledge aids in the development of sustainable pest management strategies.