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XB-ART-56896
Nat Commun January 1, 2020; 11 (1): 12.
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MAP3Kinase-dependent SnRK2-kinase activation is required for abscisic acid signal transduction and rapid osmotic stress response.

Takahashi Y , Zhang J , Hsu PK , Ceciliato PHO , Zhang L , Dubeaux G , Munemasa S , Ge C , Zhao Y , Hauser F , Schroeder JI .


Abstract
Abiotic stresses, including drought and salinity, trigger a complex osmotic-stress and abscisic acid (ABA) signal transduction network. The core ABA signalling components are snf1-related protein kinase2s (SnRK2s), which are activated by ABA-triggered inhibition of type-2C protein-phosphatases (PP2Cs). SnRK2 kinases are also activated by a rapid, largely unknown, ABA-independent osmotic-stress signalling pathway. Here, through a combination of a redundancy-circumventing genetic screen and biochemical analyses, we have identified functionally-redundant MAPKK-kinases (M3Ks) that are necessary for activation of SnRK2 kinases. These M3Ks phosphorylate a specific SnRK2/OST1 site, which is indispensable for ABA-induced reactivation of PP2C-dephosphorylated SnRK2 kinases. ABA-triggered SnRK2 activation, transcription factor phosphorylation and SLAC1 activation require these M3Ks in vitro and in plants. M3K triple knock-out plants show reduced ABA sensitivity and strongly impaired rapid osmotic-stress-induced SnRK2 activation. These findings demonstrate that this M3K clade is required for ABA- and osmotic-stress-activation of SnRK2 kinases, enabling robust ABA and osmotic stress signal transduction.

PubMed ID: 31896774
PMC ID: PMC6940395
Article link: Nat Commun
Grant support: [+]

Species referenced: Xenopus laevis
Genes referenced: rpn1 slc31a1


Article Images: [+] show captions
References [+] :
, Mitogen-activated protein kinase cascades in plants: a new nomenclature. 2002, Pubmed