Exposure of barley plants to low P_i leads to rapid changes in root respiration that correlate with specific alterations in amino acid substrates

Abstract

SummaryThe majority of inorganic phosphate (P i ) stress studies in plants have focused on the response after growth has been retarded. Evidence from transcript analysis, however, shows that a P i -stress specific response is initiated within minutes of transfer to low P i and in crop plants precedes the expression of P i transporters and depletion of vacuolar P i reserves by days.In order to investigate the physiological and metabolic events during early exposure to low P i in grain crops, we monitored the response of whole barley plants during the first hours following P i withdrawal.Lowering the concentration of P i led to rapid changes in root respiration and leaf gas exchange throughout the early phase of the light course. Combining amino and organic acid analysis with 15 N labelling we show a root-specific effect on nitrogen metabolism linked to specific substrates of respiration as soon as 1 h following P i withdrawal; this explains the respiratory responses observed and was confirmed by stimulation of respiration by exogenous addition of these respiratory substrates to roots. The rapid adjustment of substrates for respiration in roots during short-term P i -stress is highlighted and this could help guide roots towards P i -rich soil patches without compromising biomass accumulation of the plant.

Mitochondrial and Chloroplast Stress Responses Are Modulated in Distinct Touch and Chemical Inhibition Phases

“…Recent metabolic studies have suggested a role for dicarboxylates in rapid respiratory responses to Pi starvation, and DICs are indeed induced within 1 h of transfer of plants to Pi depleted medium (Lin et al, 2011;Alexova et al, 2015). Rapid transcriptional responses within 10 min have also been found in response to high-light treatment and involve chloroplast-located triose phosphate/phosphate translocator (TPT; Vogel et al, 2014).…”

Complementary Amplicon-Based Genomic Approaches for the Study of Fungal Communities in Humans

“…On the other hand, false-positive sequencing results from high-throughput sequencing methods can occur and have been described in recent literature. Putative mechanisms that have been suggested include low-level contamination, sequence errors introduced during PCR (to generate amplicons) or sequencing, and oxidation of DNA during the library preparation step [ 37 , 38 , 39 , 40 ]. The latter two issues have the potential to introduce nucleotide polymorphisms that could affect taxonomic designations.…”

Energy costs of salt tolerance in crop plants

“…(FW) h À1 (Alexova et al, 2015;Scafaro et al, 2017) ATP produced by respiration (O 2 consumption) ATP : O 2 is 4.5 (Box 2) Root surface area : FW ratio: 70 cm 2 g À1 (FW) (W. Fricke, pers. com.)…”