Non-targeted profiling of semi-polar metabolites in Arabidopsis root exudates uncovers a role for coumarin secretion and lignification during the local response to phosphate limitation

Abstract

HighlightRoot exudate metabolite profiling suggests antagonistic roles for individual coumarins during phosphate and iron deficiency. Oligolignol accumulation and root lignification indicate impaired oligolignol polymerization in local phosphate deficiency response mutants.

The effects of diversified phosphorus nutrition on the growth of oat (Avena sativa L.) and acid phosphatase activity

“…Some reports indicated that also other root exudates, such as organic acids, are important for crop plants under Pi deficiency [16][17][18]26,48]. However, the decrease of pH in the nutrient media (and rhizosphere) was not observed in our experimental conditions (data not shown) [49], which suggested that oat plants did not respond to Pi starvation via increased exudation of protons or organic acids from the roots.…”

“…1). Split-root system techniques were used in several studies to investigate the impact of an uneven distribution of nutrients, e.g., nitrogen or P on ions uptake by roots and other root features, as dependent on local signals [11,15,16,24,39] (see also [43] and studies cited therein). Our results suggested that local signal of relatively short-term Pi deficiency in about half of the divided root system was not sufficient to affect significantly oat growth or Pi content in plant tissues in our experimental conditions (Tab.…”

“…The reorganization of root system architecture is thought to be a local response of plants to Pi deficiency conditions [12,14]. Recent reports indicated that changes in Pi availability in soil are locally sensed by root tips and root growth is adjusted via modulating division and expansion of cells [14][15][16]. LPR1/LPR2 (LOW PHOSPHATE ROOT 1,2) and PDR2 (PHOSPHATE DEFICIENCY RESPONSE 2) gene products are probably key components of root Pi sensing [7,15].…”

“…LPR1/LPR2 (LOW PHOSPHATE ROOT 1,2) and PDR2 (PHOSPHATE DEFICIENCY RESPONSE 2) gene products are probably key components of root Pi sensing [7,15]. Low Pi supply induces high-affinity phosphate transporters in root cells as well as exudation of various compounds from roots, such as organic acid and protons, which are able to increase Pi availability by mobilization of insoluble Fe, Ca, and Al phosphates, via pH changes in the rhizosphere or utilization of organic esters of P by (non)specific enzyme activities [5,[16][17][18]. Alternatively, plants are developing specialized cluster/proteoid roots or can activate root colonization by mycorrhizal fungi and/or rhizosphere bacteria [5,12,[18][19][20][21].…”

“…Phosphate starvation often affects metabolic processes in shoots, e.g., photosynthesis and respiration or causes alterations in the partitioning of assimilated carbon into sucrose/starch pathways through the regulation of gene expression and/or protein phosphorylation [2,4,22,23]. Most of these reactions of plants are believed to be a systemic response, including metabolic adjustments for more efficient Pi recycling under deficient conditions [14,16,24].…”