Metabolic Adaptations of White Lupin Roots and Shoots under Phosphorus Deficiency

Abstract

White lupin (Lupinus albus L.) is highly adapted to phosphorus-diminished soils. P-deficient white lupin plants modify their root architecture and physiology to acquire sparingly available soil phosphorus. We employed gas chromatography–mass spectrometry (GC-MS) for metabolic profiling of P-deficient white lupins, to investigate biochemical pathways involved in the P-acquiring strategy. After 14 days of P-deficiency, plants showed reduced levels of fructose, glucose, and sucrose in shoots. Phosphorylated metabolites such as glucose-6-phosphate, fructose-6-phosphate, myo-inositol-phosphate and glycerol-3-phosphate were reduced in both shoots and roots. After 22 days of P-deficiency, no effect on shoot or root sugar metabolite levels was found, but the levels of phosphorylated metabolites were further reduced. Organic acids, amino acids and several shikimate pathway products showed enhanced levels in 22-day-old P-deficient roots and shoots. These results indicate that P-deficient white lupins adapt their carbohydrate partitioning between shoot and root in order to supply their growing root system as an early response to P-deficiency. Organic acids are released into the rhizosphere to mobilize phosphorus from soil particles. A longer period of P-deficiency leads to scavenging of Pi from P-containing metabolites and reduced protein anabolism, but enhanced formation of secondary metabolites. The latter can serve as stress protection molecules or actively acquire phosphorus from the soil.

Expression of plasma membrane H+‐ATPase in cluster roots of white lupin under phosphorus deficiency

“…Therefore, it is likely that cell division was inhibited under P deficiency leading to reduced growth. These results are consistent with those obtained in similar studies (Yan et al, 2002;Funayama-Noguchi et al, 2015;Mü ller et al, 2015).…”

Metabolite profiling and genome‐wide association studies reveal response mechanisms of phosphorus deficiency in maize seedling

“…The first strategy is to enhance the expression of genes encoding metabolic proteins like glycolytic enzymes and mitochondrial electron transporters that do not require phosphorus (López‐Arredondo et al ., ). The second strategy is to enhance the scavenging of internal phosphorus, including from phospholipids, small phosphorylated metabolites and RNA (López‐Arredondo et al ., ; Müller et al ., ). In this investigation, a significant decrease in the levels of almost all phosphorylated metabolites was observed under Pi‐deficient conditions, a result in accord with previous reports in Arabidopsis, maize, and white lupin (Ganie et al ., ; Müller et al ., ; Pant et al ., ), suggesting that the maintenance of cellular phosphorus homeostasis by the recycling of phosphorylated metabolites is a ubiquitous strategy among plants.…”

“…In the case of Zea mays (maize), metabolomics has been used for the characterization of responses to abiotic stress and inoculation with nitrogen‐fixing plant‐interacting bacteria (Ganie et al ., ; Obata et al ., ; Brusamarello‐Santos et al ., ), the association of leaf physiology with kernel yield, the complex metabolism of the maize kernel (Wen et al ., , ; Cañas et al ., ) and the mechanism for the induction of genotype‐dependent embryonic callus (Ge et al ., ). Additionally, previous studies on the metabolic variations under low‐Pi conditions have been conducted in Arabidopsis and white lupin (Müller et al ., ; Pant et al ., ). Specifically, studies showed that plant secondary metabolites are responding to environmental stresses and are associated with direct or indirect resistance to herbivores (Kessler and Kalske, ).…”

Transcriptome and metabolome analysis provide insights into root and root released organic anion responses to phosphorus deficiency in oat

“…In white lupin, enhanced levels of citrate were observed in roots (2.2 fold) and cluster roots (7.6 fold) after 22 days P deficiency, whereas after 14 days P deficiency the changes were 1.4 and 3.5 fold, respectively (Müller et al , 2015), suggesting that changes in the metabolome mainly occurred after long-term P deficiency. Our oat root metabolome analysis indicated that most organic acids showed a general reduction after 10 days of P deficiency, which corresponded well with common bean roots after 21 days of low-P treatment (Hernández et al , 2007), while slight (but not significant) increases in citric and malic acids were detected in our study.…”