Identification of Phosphatin, a Drug Alleviating Phosphate Starvation Responses in Arabidopsis      

Abstract

Inorganic phosphate (Pi) is present in most soils at suboptimal concentrations, strongly limiting plant development. Plants have the ability to sense and adapt to the surrounding ionic environment, and several genes involved in the response to Pi starvation have been identified. However, a global understanding of the regulatory mechanisms involved in this process is still elusive. Here, we have initiated a chemical genetics approach and isolated compounds that inhibit the response to Pi starvation in Arabidopsis (Arabidopsis thaliana). Molecules were screened for their ability to inhibit the expression of a Pi starvation marker gene (the high-affinity Pi transporter PHT1;4). A drug family named Phosphatin (PTN; Pi starvation inhibitor), whose members act as partial suppressors of Pi starvation responses, was thus identified. PTN addition also reduced various traits of Pi starvation, such as phospholipid/glycolipid conversion, and the accumulation of starch and anthocyanins. A transcriptomic assay revealed a broad impact of PTN on the expression of many genes regulated by low Pi availability. Despite the reduced amount of Pi transporters and resulting reduced Pi uptake capacity, no reduction of Pi content was observed. In addition, PTN improved plant growth; this reveals that the developmental restrictions induced by Pi starvation are not a consequence of metabolic limitation but a result of genetic regulation. This highlights the existence of signal transduction pathway(s) that limit plant development under the Pi starvation condition.

Silicon Compensates Phosphorus Deficit-Induced Growth Inhibition by Improving Photosynthetic Capacity, Antioxidant Potential, and Nutrient Homeostasis in Tomato

“…Notably, P deficit conditions lead to breakdown of phospholipids in the chloroplast membranes to release Pi, which could be a potential reason for reduced photosynthetic rate [42]. In addition, enhanced carbohydrate (starch and sugars) accumulation in chloroplasts under Pi-depleted conditions may also result in attenuated photosynthetic activity [42,43]. However, exogenous Si application significantly increased photosynthetic pigment contents as well as net photosynthetic rate under LP stress compared with that under LP stress alone.…”

S‐Nitrosoglutathione works downstream of nitric oxide to mediate iron‐deficiency signaling in Arabidopsis

“…Chemical biology allows the use of small molecules to dose-dependently activate the function of a specific protein or disrupt the function of redundant proteins, thus eliminating plant lethality (Hicks and Raikhel, 2012;Serrano et al, 2015). Small-molecule-based chemical screening has been successfully used in many fields such as hormone signaling to identify receptors and phosphate homeostasis to dissect the molecular response (De Rybel et al, 2009;Park et al, 2009;Arnaud et al, 2014;Bonnot et al, 2016). Functional redundancy due to the overlapping roles of members within gene families, bHLH subgroups Ib and IVc, and lethality like FIT knockout appear to be limiting factors specifically altering the Fe-signaling network Wang et al, 2013;Zhang et al, 2015;Li et al, 2016;Liang et al, 2017).…”

Self‐Sorting Effects in the Self‐Assembly of Metallosupramolecular Rhombi from Chiral BINOL‐Derived Bis(pyridine) Ligands

“…There are various mechanisms of plant adaptation to low P availability ( Ticconi et al, 2004; Wissuwa et al, 2005; Arnaud et al, 2014). They include elongation of root systems to enhance the exploited soil volume ( Ticconi et al, 2004), exudation of organic anions and protons to mobilize P from insoluble forms ( Jones and Darrah , 1994), and secretion of phosphatases by roots and microorganisms ( Wasaki et al, 2009).…”

“…In environments with low P availability, plants modify their metabolic processes for efficient P use by inducing changes in the lipid composition of plasma membranes, by increasing P i transporter activity in root tissues, by building new temporal starch and anthocyanins, and by differentiating gene expression ( Ticconi et al, 2004; Wissuwa et al, 2005; Arnaud et al, 2014; Hufnagel et al, 2014). These responses are a combination of general stress‐related responses and P‐specific signaling cascades.…”