Impact of silicate and selenate amendments on low molecular weight peptide production in arsenate-stressed rice seedlings

Plants effectively manage various environmental stresses by synthesizing low molecular weight peptides. In our previous studies, we explored the impact of As(V) with or without the supplementation of Si or Se, on growth, total As, As(V), As(III), Si and Se contents, oxidative stress markers, antioxidant enzymes activities, chlorophyll contents, photosynthetic parameters, respiratory enzymes activities, thiol metabolism and phytochelatin synthesis in the rice (Oryza sativa L. cv. MTU-1010) seedlings. The present study extends this research by isolating and characterizing low molecular weight peptides from rice seedlings under non-stressed, As(V)-stressed, and Si-Se treated conditions. Efforts were undertaken to isolate low molecular weight peptides from rice seedlings subjected to various conditions, including non-stressed, As(V) stressed, and Si-Se treated states, with the aim to quantify their differences and determine their molecular weights using MALDI-TOF and HPLC analysis. Additionally, the antioxidant capabilities of these peptides were investigated under As(V) exposure. Following this, bioassays were conducted to evaluate the impact of these peptides on relevant physiological aspects. Notably, peptide abundance was highest in control, Si and Se treated rice seedlings, but decreased significantly under As(V) stressed conditions. Supplementation with Si and Se in As(V)-treated rice seedlings alleviated these challenges to differing degrees, leading to enhanced germination and growth of the rice seedlings.