Epoxycarotenoid‐mediated synthesis of abscisic acid in Physcomitrella patens implicating conserved mechanisms for acclimation to hyperosmosis in embryophytes. Issue 1 (24th December 2014)

• Record Type: Journal Article
• Authors: Takezawa, Daisuke; Watanabe, Naoki; Ghosh, Totan Kumar; Saruhashi, Masashi; Suzuki, Atsushi; Ishiyama, Kanako; Somemiya, Shinnosuke; Kobayashi, Masatomo; Sakata, Yoichi
• Is Part Of: New phytologist. Volume 206:Issue 1(2015)
• Page Start: 209
• Page End: 219
• Publication Date: 2014-12-24
• Subjects: Botany -- Periodicals; 580
• DOI: 10.1111/nph.13231
• Languages: English
• ISSNs: 0028-646X

Abstract

<abstract abstract-type="main" id="nph13231-abs-0001"> <title>Summary</title> <p> <list id="nph13231-list-0001" list-type="bullet"> <list-item> <p>Plants acclimate to environmental stress signals such as cold, drought and hypersalinity, and provoke internal protective mechanisms. Abscisic acid (ABA), a carotenoid‐derived phytohormone, which increases in response to the stress signals above, has been suggested to play a key role in the acclimation process in angiosperms, but the role of ABA in basal land plants such as mosses, including its biosynthetic pathways, has not been clarified.</p> </list-item> <list-item> <p>Targeted gene disruption of <italic>PpABA1</italic>, encoding zeaxanthin epoxidase in the moss <italic>Physcomitrella patens</italic> was conducted to determine the role of endogenous ABA in acclimation processes in mosses.</p> </list-item> <list-item> <p>The generated <italic>ppaba1</italic> plants were found to accumulate only a small amount of endogenous ABA. The <italic>ppaba1</italic> plants showed reduced osmotic acclimation capacity in correlation with reduced dehydration tolerance and accumulation of late embryogenesis abundant proteins. By contrast, cold‐induced freezing tolerance was less affected in <italic>ppaba1</italic>, indicating that endogenous ABA does not play a major role in the regulation of cold acclimation in the moss.</p> </list-item> <list-item> <p>Our results suggest that the mechanisms for osmotic acclimation mediated by carotenoid‐derived synthesis of ABA are conserved in embryophytes and that acquisition of the mechanisms played a crucial role in terrestrial adaptation and colonization by land plant ancestors.</p> </list-item> </list> </p> </abstract>