Phosphoproteomic profiling reveals ABA‐responsive phosphosignaling pathways in Physcomitrella patens

Abstract

Abscisic acid (ABA) and its signaling system are important for land plants to survive in terrestrial conditions. Here, we took a phosphoproteomic approach to elucidate the ABA signaling network in Physcomitrella patens, a model species of basal land plants. Our phosphoproteomic analysis detected 4630 phosphopeptides from wild-type P. patens and two ABA-responsive mutants, a disruptant of group-A type-2C protein phosphatase (PP2C; ppabi1a/b) and AR7, a defective mutant in ARK, identified as an upstream regulator of SnRK2. Quantitative analysis detected 143 ABA-responsive phosphopeptides in P. patens. The analysis indicated that SnRK2-mediated phosphorylation and target motifs were partially conserved in bryophytes. Our data demonstrate that the PpSnRK2B and AREB/ABF-type transcription factors are phosphorylated in vivo in response to ABA under the control of ARK. On the other hand, our data also revealed the following: (i) the entire ABA-responsive phosphoproteome in P. patens is quite diverse; (ii) P. patens PP2C affects additional pathways other than the known ABA signaling pathway; and (iii) ARK is mainly involved in ABA signaling. Taken together, we propose that the core ABA signaling pathway is essential in all land plants; however, some ABA-responsive phosphosignaling uniquely developed in bryophytes during the evolutionary process.

Evolution of Abscisic Acid Signaling Module and Its Perception

“…For detailed ABRE/ ABFs evolution see Cuming (2019). In addition, PpSnRK2s from P. patens and Arabidopsis SnRK2.6/OST1 phosphorylated in vitro the same ABA-responsive phosphopeptides (Amagai et al, 2018). Thus, not only is the kinase itself highly conserved, but also the cellular targets of class III SnRK2 are highly conserved, both from algae through angiosperms.…”

The phosphoproteomic responses of duck (Cairna moschata) to classical/novel duck reovirus infections in the spleen tissue

“…Protein phosphorylation is a universal PTM; however, the abundance of phosphorylation largely varies among different species. In C. moschata, the abundance of phosphorylated protein (2,853 phosphorylated proteins) was higher than most of the published species, such as Sus domesticus (966 phosphorylated proteins), Bombyx mori (2,112 phosphorylated proteins), Kandelia candel (1,516 phosphorylated proteins), Nicotiana tabacum (1,311 phosphorylated proteins), Lotus japonicus (1,154 phosphorylated proteins), Ammopiptanthus mongolicus (2,019 phosphorylated proteins), Catalpa fargesii (1,646 phosphorylated proteins), Abelmoschus esculentus (2,550 phosphorylated proteins), and Physcomitrella patens (1,873 phosphorylated proteins) 35,43,45,[50][51][52][53] . High-throughput method gives us an opportunity to screen potential phosphorylated proteins and reveal the involvement of protein phosphorylation in the responses to the C/NDRV infections.…”

Rebuilding core abscisic acid signaling pathways of Arabidopsis in yeast

“…Consistently, SnRK2.2 and SnRK2.3 were not active in yeast and possibly require the additional expression of an upstream‐acting protein kinase in yeast. Candidates for such an activator might be the protein kinases BIN2 (Cai et al , ) and a mitogen‐activated protein kinase kinase kinase shown to activate SnRK2s under hyperosmotic stress in the moss Physcomitrella patens (Saruhashi et al , ; Amagai et al , ). Besides OST1, the subgroup I members SnRK2.1, SnRK2.4, SnRK2.5, and SnRK2.10 stimulated ABA signaling in our analysis.…”