AUTHOR=Pii Youry , Alessandrini Massimiliano , Dall’Osto Luca , Guardini Katia , Prinsi Bhakti , Espen Luca , Zamboni Anita , Varanini Zeno 

TITLE=Time-Resolved Investigation of Molecular Components Involved in the Induction of NO3– High Affinity Transport System in Maize Roots

JOURNAL=Frontiers in Plant Science

VOLUME=7

YEAR=2016

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2016.01657

DOI=10.3389/fpls.2016.01657

ISSN=1664-462X

ABSTRACT=<p>The induction, i.e., the rapid increase of nitrate (<inline-formula><mml:math id="M2" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msubsup><mml:mi mathvariant="normal" mathcolor="black">NO</mml:mi><mml:mi mathvariant="normal" mathcolor="black">3</mml:mi><mml:mn mathvariant="normal" mathcolor="black">–</mml:mn></mml:msubsup></mml:math></inline-formula>) uptake following the exposure of roots to the anion, was studied integrating physiological and molecular levels in maize roots. Responses to <inline-formula><mml:math id="M3" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msubsup><mml:mi mathvariant="normal" mathcolor="black">NO</mml:mi><mml:mi mathvariant="normal" mathcolor="black">3</mml:mi><mml:mn mathvariant="normal" mathcolor="black">–</mml:mn></mml:msubsup></mml:math></inline-formula> treatment were characterized in terms of changes in <inline-formula><mml:math id="M4" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msubsup><mml:mi mathvariant="normal" mathcolor="black">NO</mml:mi><mml:mi mathvariant="normal" mathcolor="black">3</mml:mi><mml:mn mathvariant="normal" mathcolor="black">–</mml:mn></mml:msubsup></mml:math></inline-formula> uptake rate and plasma membrane (PM) H<sup>+</sup>-ATPase activity and related to transcriptional and protein profiles of <italic>NRT2, NRT3</italic>, and <italic>PM H<sup>+</sup>-ATPase</italic> gene families. The behavior of transcripts and proteins of <italic>ZmNRT2s</italic> and <italic>ZmNRT3s</italic> suggested that the regulation of the activity of inducible high-affinity transport system (iHATS) is mainly based on the transcriptional/translational modulation of the accessory protein ZmNRT3.1A. Furthermore, ZmNRT2.1 and ZmNRT3.1A appear to be associated in a ∼150 kDa oligomer. The expression trend during the induction of the 11 identified <italic>PM H<sup>+</sup>-ATPase</italic> transcripts indicates that those mainly involved in the response to <inline-formula><mml:math id="M5" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msubsup><mml:mi mathvariant="normal" mathcolor="black">NO</mml:mi><mml:mi mathvariant="normal" mathcolor="black">3</mml:mi><mml:mn mathvariant="normal" mathcolor="black">–</mml:mn></mml:msubsup></mml:math></inline-formula> treatment are <italic>ZmHA2</italic> and <italic>ZmHA4</italic>. Yet, partial correlation between the gene expression, protein levels and enzyme activity suggests an involvement of post-transcriptional and post-translational mechanisms of regulation. A non-denaturing Deriphat-PAGE approach allowed demonstrating for the first time that PM H<sup>+</sup>-ATPase can occur <italic>in vivo</italic> as hexameric complex together with the already described monomeric and dimeric forms.</p>