Response of Arabidopsis thaliana root growth to phosphorus and its relation to media chemical composition

Abstract

The interaction between phosphorus (P) and other media components alters root development and masks the plant response and thus limits the ability to correctly identify P-deficiency response (pdr) mutants. This study aims to assess changes in root development caused by different composition of growth media normally used in Arabidopsis research and to study their effects on pdr-mutant screening. Primary root growth of four genotypes was analyzed in media differing in P concentrations: half-strength Murashige and Skoog (½ MS) and Somerville and Ogren (SO). The effects of nitrogen source and Fe on root growth were investigated in each medium separately and in a mixture. We found that the primary root length of all genotypes grown on ½ MS was reduced in comparison with plants grown on SO medium. The mutant pdr9 was the most sensitive in ½ MS, This mutant was also hypersensitive to Fe that intensified its sensitivity to ammonium. Ammonium increased the root inhibition caused by Fe also in wild-type plants. In conclusion, on the basis of our study we recommend to use SO medium, which ensures an efficient selection to screen for pdr mutants through root growth. Moreover, nitrogen sources in the media other than nitrate should be taken carefully.

Buffered delivery of phosphate to Arabidopsis alters responses to low phosphate

“…The complex interactions between micro- and macronutrients in media have been described ( Misson et al , 2005 ; Gruber et al , 2013 ; Kellermeier et al , 2014 ). Recently, Strieder et al (2017) grew plants on modified, Pi-limited Somerville and Ogren (SO) and half-strength Murashige and Skoog (MS) media and found that the phosphate deficiency response9 ( pdr9 ) mutant of Arabidopsis is not actually a Pi-sensitive mutant as previously reported ( Chen et al , 2000 ), but rather is hypersensitive to ammonium and Fe. Though using alternative media may eliminate certain confounding nutrient conditions, the Pi is still unbuffered.…”

“…The classic gel media system has come under scrutiny previously, as have similar hydroponic methods. The gelling agents used ( Jain et al , 2009 ; Gruber et al , 2013 ), pH of the media ( Svistoonoff et al , 2007 ), exposure of roots to light ( Xu et al , 2013 ; Rellán-Álvarez et al , 2015 ), and nutrient composition ( Strieder et al , 2017 ) have all been shown to affect plant responses to nutrient stress. The complex interactions between micro- and macronutrients in media have been described ( Misson et al , 2005 ; Gruber et al , 2013 ; Kellermeier et al , 2014 ).…”

“…Genes involved in the maintenance or control of primary root elongation under low-Pi conditions have been identified by examining the elongation of mutants under various Pi conditions ( Chen et al , 2000 ; Sánchez-Calderón et al , 2006 ; Svistoonoff et al , 2007 ; Ticconi et al , 2009 ; Wang et al , 2010 a ; Strieder et al , 2017 ). Here, we show that although primary root length decreased under low, buffered conditions, the decrease was not as drastic as what is observed under unbuffered conditions.…”

Root developmental responses to phosphorus nutrition

“…An agarose medium that causes a strong inhibition of PR growth, in contrast, is suitable for screening of mutants (like lpr1, stop1 , and almt1 ) whose PR growth is insensitive to inhibition by P deficiency (Sánchez‐Calderón et al, 2005; Svistoonoff et al, 2007; Wang et al, 2019; Figure 4). Researchers have also reported that the same mutant could show different sensitivity of PR growth in the different −Pi media (Strieder et al, 2017).…”

Food for thought: how nutrients regulate root system architecture

“…Cross-talk between phosphate and heavy metal nutrients such as iron and zinc has long been appreciated. In particular, the phosphate starvation-induced inhibition of PR growth has been shown to be dependent on the availability of iron [ 35 ], which is likely to be due to the importance of Fe 3+ in the PDR2-LPR1 signalling module [ 26 •• ]. LPR1 protein exhibits dual sub-cellular localization in the endoplasmic reticulum and in the cell wall, but is considered to function primarily as a cell wall ferroxidase.…”