PHOSPHATE STARVATION RESPONSE1 (PHR1) interacts with JASMONATE ZIM-DOMAIN (JAZ) and MYC2 to modulate phosphate deficiency-induced jasmonate signaling in Arabidopsis

Abstract

Phosphorus (P) is a macronutrient necessary for plant growth and development. Inorganic phosphate (Pi) deficiency modulates the signaling pathway of the phytohormone jasmonate in Arabidopsis thaliana, but the underlying molecular mechanism currently remains elusive. Here, we confirmed that jasmonate signaling was enhanced under low Pi conditions, and the CORONATINE INSENSITIVE1 (COI1)-mediated pathway is critical for this process. A mechanistic investigation revealed that several JASMONATE ZIM-DOMAIN (JAZ) repressors physically interacted with the Pi signaling-related core transcription factors PHOSPHATE STARVATION RESPONSE1 (PHR1), PHR1-LIKE2 (PHL2), and PHL3. Phenotypic analyses showed that PHR1 and its homologs positively regulated jasmonate-induced anthocyanin accumulation and root growth inhibition. PHR1 stimulated the expression of several jasmonate-responsive genes, whereas JAZ proteins interfered with its transcriptional function. Furthermore, PHR1 physically associated with the basic helix-loop-helix (bHLH) transcription factors MYC2, MYC3, and MYC4. Genetic analyses and biochemical assays indicated that PHR1 and MYC2 synergistically increased the transcription of downstream jasmonate-responsive genes and enhanced the responses to jasmonate. Collectively, our study reveals the crucial regulatory roles of PHR1 in modulating jasmonate responses, and provides a mechanistic understanding of how PHR1 functions together with JAZ and MYC2 to maintain the appropriate level of jasmonate signaling under conditions of Pi deficiency.

SlPHL1 positively modulates acid phosphatase in response to phosphate starvation by directly activating the genes SlPAP10b and SlPAP15 in tomato

“…The p-value for each comparison between the two data sets is displayed above the asterisk. The experiments were repeated three times with similar results.process of jasmonate-induced anthocyanin synthesis along with its homologs AtPHL1, AtPHL2, and AtPHL3(He et al, 2023). Similarly,Liao et al (2022) recently demonstrated that multiple SlPHR proteins play a role in the suppression of AM symbiosis by LP stress in tomato.It is, therefore, highly likely that SlPHL1 and other SlPHRs work together to regulate APase activity in a functionally redundant manner.…”

“…Both AtPHR1 and AtPHL2 can directly regulate the transcriptional expression of AtPAP10 to enhance APase activity in response to LP stress (Sun et al, 2016). Also, AtPHR1 was thought to be a key regulator involved in the regulation of LP‐induced anthocyanin synthesis (Bustos et al, 2010; He et al, 2021; Liu et al, 2022), but it was recently discovered to be involved in the process of jasmonate‐induced anthocyanin synthesis along with its homologs AtPHL1, AtPHL2, and AtPHL3 (He et al, 2023). Similarly, Liao et al (2022) recently demonstrated that multiple SlPHR proteins play a role in the suppression of AM symbiosis by LP stress in tomato.…”

Plant pathogenic fungi hijack phosphate starvation signaling with conserved enzymatic effectors

“…Phosphate status and jasmonate signaling are intricately linked in plants. For example, jasmonate treatment stimulates PP-InsP synthesis ( 49 ), and PHR-activation enhances jasmonate production and signaling ( 50, 51 ). By manipulating intracellular PP-InsP levels, the Nudix effectors may influence jasmonate and auxin signaling in their host plants in addition to inducing starvation responses.…”

Inducer of CBF Expression 1 (ICE1) Promotes Cold-enhanced Immunity by Directly Activating Salicylic Acid Signaling

“…The plasmids were transformed into Agrobacterium tumefaciens strain GV3101 and injected into tobacco ( N. benthamiana ) leaves. As described previously (He et al, 2023; Li et al, 2023), YFP and 4,6-diamidino-2-phenylindole (DAPI) fluorescence of infected leaves were observed under a confocal laser scanning microscope (Olympus) after 48 h of co-expression. Primers used for cloning are listed in Supplemental Data Set 1.…”