Short Exposure to Full Moonlight Has a Long-Term Impact on Brassica juncea Cell Activity and Growth

Lunar farming, often regarded as a myth, is regularly practiced in many places around the world (e.g., India) where framers organized their agricultural activities according to moon phases. Early and recent work showed that exposure to moonlight affects the life cycle of plants, from seed germination and vegetative growth to fruit maturation and dispersal. Here we addressed the long-term effect of short exposure to full moonlight (FML) on cellular activities in Brassica juncea by analyzing protein and metabolite profiles immediately after 3-night-exposure (3NE) or 7 and 15 days after exposure (DAE) to FML. This study shows an increase in nuclear size following 3NE to FML, which was accompanied by changes in protein and metabolite profiles. We identified significant alterations in protein and metabolite profiles between FML and dark-treated plants in conjunction with developmental stages, which persisted long after exposure to FML. Most notable are the changes in composition of metabolite interconversion enzymes (MIEs) at various developmental stages which were intensified in FML-treated plants. Changes in MIEs were accompanied by significant alterations in metabolite composition and level, particularly at 15DAE, including branched-chain amino acids (e.g., valine, leucine), multiple sugars (raffinose, glucose, sucrose) as well as the tricarboxylic acid (TCA) cycle intermediates malic acid and citric acid. Thus, our results show that short-term exposure to FML triggers a developmental switch resulting in a long-term impact on plant performance that brings about an increase in cell activities and consequently enhanced growth. Our results call for meticulous research on this lunar phenomenon and its potential to enhance crop plant growth and development.