Metabolic responses to potassium availability and waterlogging reshape respiration and carbon use efficiency in oil palm.

Oil palm is by far the major oil-producing crop at the global scale, with ≈62 Mt oil produced each year. This species is a strong potassium (K)-demanding species cultivated in regions where soil K availability is generally low and waterlogging due to tropical heavy rains can limit further nutrient absorption. However, the metabolic effects of K and waterlogging have never been assessed precisely. Here, we examined the metabolic response of oil palm saplings in the greenhouse under controlled conditions (nutrient composition with low or high K availability, with or without waterlogging), using gas exchange, metabolomics and proteomics analyses. Our results show that both low K and waterlogging have a detrimental effect on photosynthesis but stimulate leaf respiration, with differential accumulation of typical metabolic intermediates and enzymes of the Krebs cycle and alternative catabolic pathways. In addition, we found a strong relationship between metabolic composition, the rate of leaf dark respiration, and cumulated respiratory loss. Advert environmental conditions (here, low K and waterlogging) thus have an enormous impact on respiration in oil palm. Leaf metabolome and proteome appear to be good predictors of carbon balance, and open avenues for cultivation biomonitoring using functional genomics technologies. This article is protected by copyright. All rights reserved.