Ethylene signalling is involved in regulation of phosphate starvation‐induced gene expression and production of acid phosphatases and anthocyanin in Arabidopsis

Abstract

Summary With the exception of root hair development, the role of the phytohormone ethylene is not clear in other aspects of plant responses to inorganic phosphate (Pi) starvation. The induction of AtPT2 was used as a marker to find novel signalling components involved in plant responses to Pi starvation. Using genetic and chemical approaches, we examined the role of ethylene in the regulation of plant responses to Pi starvation. hps2, an Arabidopsis mutant with enhanced sensitivity to Pi starvation, was identified and found to be a new allele of CTR1 that is a key negative regulator of ethylene responses. 1‐aminocyclopropane‐1‐carboxylic acid (ACC), the precursor of ethylene, increases plant sensitivity to Pi starvation, whereas the ethylene perception inhibitor Ag+ suppresses this response. The Pi starvation‐induced gene expression and acid phosphatase activity are also enhanced in the hps2 mutant, but suppressed in the ethylene‐insensitive mutant ein2‐5. By contrast, we found that ethylene signalling plays a negative role in Pi starvation‐induced anthocyanin production. These findings extend the roles of ethylene in the regulation of plant responses to Pi starvation and will help us to gain a better understanding of the molecular mechanism underlying these responses.

Dissection of the Control of Anion Homeostasis by Associative Transcriptomics in Brassica napus

“…Particularly interesting is the identification of two genes involved in ethylene signaling, ETHYLENE INSENSITIVE2 (EIN2) and EIN5, associated with variation in sulfate and phosphate levels, respectively. Ethylene signaling is involved in several responses to phosphate deficiency: the regulation of gene expression, production of acid phosphatases, and accumulation of anthocyanins (Lei et al, 2011). Even more evidence is present on the role of ethylene in the regulation of the sulfate starvation response.…”

Similarities and Differences in the Acquisition of Fe and P by Dicot Plants

“…The application of ACC, the precursor of ethylene synthesis, increased AtPT2 expression while the application of Ag + , an inhibitor of ethylene action completely blocked it. Furthermore, these authors found that AtPT2 expression was significantly reduced in the Arabidopsis ethylene insensitive mutants in2-5 and etr1-1 under conditions of P deficiency [69]. In addition to AtPT2 (Pht1;4), the AtPht1;1 gene, which encodes another transporter responsible for acquiring P from soil, also increased its expression under ACC (1-aminocyclopropane-1-carboxylic acid) treatment and reduced it with Ag + , demonstrating that ethylene is involved in the regulation of the induction of both P transporters [69,97].…”

“…At the same time, Borch et al [66] showed the participation of ethylene in the regulation of P deficiency responses. At present, although the regulation of the genes related to these responses is not totally known, ethylene has been involved in the activation of both Fe acquisition-related genes (AtFIT, AtFRO2 and AtIRT1; [3,4,67,68] and P acquisition-related genes [69,70]). …”

“…Nowadays, however, there is evidence that ethylene also plays an important role in the regulation of physiological responses to P deficiency, as is the case with Fe deficiency [5,69,70,97,98]. Using the P transporter gene, AtPT2, as a marker gene to identify mutants with alterations in the regulation of responses to P deficiency, Lei et al [69] identified a mutant of Arabidopsis thaliana, hps2, which showed enhanced responses to P deficiency. This mutant exhibits increased AtPT2 expression under P deficiency, due to the insertion of a T-DNA in the CTR1 gene (involved in ethylene signaling; [59]).…”

“…In both deficiencies, the activating effect of auxin, ethylene and NO depend on the Fe or P status of the plants [68,69,75,76], which suggests the existence of additional Fe-and P-related signals acting in conjunction with ethylene, auxin and NO [82]. In the case of Fe, the expression of Fe acquisition genes in plants grown with low levels of Fe was activated by auxin, ethylene and NO, but they have almost no effect in plants grown with high Fe levels [67,68,75,76].…”