Moderate source-reduction improves peanut yield and quality through modulating photosynthesis, source-sink...

Source-reduction plays a critical role in coordinating source-sink balance of legume crops, it remains unclear whether source-reduction can be utilized as a strategy to enhance the pod yield and seed quality. Here, a two-year field experiment was conducted to decipher the potential effects of varying degrees of source-reduction treatment (removal of leaf and stem) on peanut (Arachis hypogaea L.) production and uncover its underlying mechanisms. Averaged for two years, minor source-reduction showed no effects on peanut yield and seed quality whereas moderate source-reduction significantly increased the peanut pod yield (11.52 %), seed protein content (3.85 %), and the ratio of seed oleic acid/linoleic acid (10.61 %). In contrast extensive source-reduction dramatically decreased the peanut yield and seed quality compared with no source-reduction. Physiological data suggested that moderate source-reduction significantly enhanced the net photosynthetic rate (8.52-13.60 %) and chlorophyll content (8.41-16.61 %) of the functional leaf. Moreover, the activities of antioxidant enzymes were further induced. Strikingly, agronomic data showed that plant biomass and nitrogen content were greater in reproductive organs (pod and needle) than in vegetative organs (leaf and stem) in the subsequent sampling stages after moderate source-reduction. Evidence from transcriptome and metabolomic analysis on peanut functional leaf indicated that pathways associated with "photosynthesis", "nitrogen metabolism", "carbon fixation", "TCA cycle", and "secondary metabolites" were enriched in moderate source-reduction treatment. Our results advocate that varying degrees of source-reduction manipulations exhibited different responses in peanut growth and yield formation. Particularly, moderate source-reduction plays a vital role in promoting peanut pod yield and seed quality through enhancing photosynthesis, strengthening antioxidant system, maintaining source-sink equilibrium, accelerating reproductive growth, and modulating secondary metabolisms.