Program

Oral Sessions

Day 2, May 16（Wed.）　10:25-10:45　Room B (Seiun 1)

2B-O1-P-1025　　PDF

Understanding of ABA-dependent phosphosignaling pathways in land plants

(¹Tokyo Univ. Agr. Tech., ²Tokyo Univ. Agr., ³Kyoto Univ., ⁴Saitama Univ., ⁵RIKEN CSRS, ⁶CSIRO, ⁷Univ. Missouri)
Anna Amagai¹, Yoshimasa Honda¹, Yurie Hara¹, Shinnosuke Ishikawa¹, Mayuri Kuwamura², Akihisa Shinozawa², Naoyuki Sugiyama³, Yasushi Ishihama³, Yoischi Sakata², Daisuke Takezawa⁴, Fuminori Takahashi⁵, Gubler Frank⁶, Barrero Jose⁶, Peck Scott⁷, Kazuo Shinozaki⁵, ^oTaishi Umezawa¹

Abscisic acid (ABA) and its signaling system are important for land plants to survive in terrestrial conditions. Protein phosphorylation/dephosphorylation has a central role in ABA signaling, mediated by protein phosphatase 2C (PP2C) and SNF1-related protein kinase 2 (SnRK2). Recently, we are taking a phosphoproteomic approach to elucidate the ABA signaling network in multi-species of land plants. For example, Physcomitrella patens is a model species of basal land plants. Our phosphoproteomic analysis detected 4,630 phosphopeptides from P. patens wild-type and two ABA-responsive mutants, such as a PP2C disruptant (ppabi1a/b), and an ARK-defective mutant (AR7), identified as an upstream regulator of SnRK2. Our data revealed: 1) the entire ABA-responsive phosphoproteome in P. patens was quite diverse, 2) P. patens PP2C regulated multiple pathways in addition to the ABA response, and 3) 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.