Heat Stress Affects Pi-related Genes Expression and Inorganic Phosphate Deposition/Accumulation in Barley

Abstract

Phosphorus (P) in plants is taken from soil as an inorganic phosphate (Pi) and is one of the most important macroelements in growth and development. Plants actively react to Pi starvation by the induced expression of Pi transporters, MIR399, MIR827, and miR399 molecular sponge – IPS1 genes and by the decreased expression of the ubiquitin-conjugating enzyme E2 (PHOSPHATE2 – PHO2) and Pi sensing and transport SPX-MFS genes. The PHO2 protein is involved in the degradation of Pi transporters PHT1;1 (from soil to roots) and PHO1 (from roots to shoots). The decreased expression of PHO2 leads to Pi accumulation in shoots. In contrast, the pho1 mutant shows a decreased level of Pi concentration in shoots. Finally, Pi starvation leads to decreased Pi concentration in all plant tissues. Little is known about plant Pi homeostasis in other abiotic stress conditions. We found that, during the first hour of heat stress, Pi accumulated in barley shoots but not in the roots, and transcriptomic data analysis as well as RT-qPCR led us to propose an explanation for this phenomenon. Pi transport inhibition from soil to roots is balanced by lower Pi efflux from roots to shoots directed by the PHO1 transporter. In shoots, the PHO2 mRNA level is decreased, leading to an increased Pi level. We concluded that Pi homeostasis in barley during heat stress is maintained by dynamic changes in Pi-related genes expression.

Genetic regulation of growth and nutrient content under phosphorus deficiency in the wild barley introgression library S42IL

“…Pacak et al. () reported on four families of inorganic phosphate transporters ( PHT1, PHT2, PHT3 and PHT4 ), which are involved in uptake and transport of inorganic phosphate. PHT1 is known as a plasma membrane located phosphate transporter, where ten homologues are present in barley.…”

“…The homologue HvPT1;6 is expressed in roots and, predominantly, in leaves and its upregulation under phosphate deficiency has been reported by Preuss, Huang, Gilliham, and Tyerman (). Based on mapping information, the barley homologue HvPT1;6 (i.e., MLOC_80912.2, Pacak et al., ) is located inside the chromosome 5H introgression of S42IL‐127. The phosphate increasing effect of the Hsp allele, present in S42IL‐127, may, thus, be explained by HvPT1;6 .…”

“…All effects were solely significant under P100 treatment, and exotic Hsp alleles increased P content in shoots compared to 'Scarlett'. The increase in phosphorus in shoots due to the action of Hsp alleles could be beneficial for barley cultivation, in particular, under P deficiency Pacak et al (2016). reported on four families of inorganic phosphate transporters (PHT1, PHT2, PHT3 and PHT4), which are involved in uptake and transport of inorganic phosphate.…”

Effects of Different Ectomycorrhizal Fungal Inoculates on the Growth of Pinus tabulaeformis Seedlings under Greenhouse Conditions

“…Phosphorus (P) is one of the most important minerals [35]. P is a component of many compounds, such as nucleic acids, ATP, and phospholipids, and it plays a role in metabolism [36][37][38]. ECM promotes P absorption from soil in two ways: (1) the hyphae absorb nutrients directly from the soil and transport those nutrients to their host plants to support growth and development; and (2) inoculation changes root shape and various biochemical characteristics of the host plant, thereby enlarging the scope of the rhizosphere and improving the absorption ability of the roots [38].…”

“…Potassium (K) exists primarily in plants as an ion and is found in areas with strong metabolic activity. It is involved in the formation of proteins and in photosynthesis, as well as in resistance to stress [37,39].…”