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The response of the maize nitrate transport system to nitrogen demand and supply across the lifecycle
Author(s) -
Garnett Trevor,
Conn Vanessa,
Plett Darren,
Conn Simon,
Zanghellini Juergen,
Mackenzie Nenah,
Enju Akiko,
Francis Karen,
Holtham Luke,
Roessner Ute,
Boughton Berin,
Bacic Antony,
Shirley Neil,
Rafalski Antoni,
Dhugga Kanwarpal,
Tester Mark,
Kaiser Brent N.
Publication year - 2013
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.12166
Subject(s) - biology , nitrogen cycle , nitrate , nitrogen , shoot , agronomy , botany , chemistry , ecology , organic chemistry
Summary An understanding of nitrate (NO 3−) uptake throughout the lifecycle of plants, and how this process responds to nitrogen ( N ) availability, is an important step towards the development of plants with improved nitrogen use efficiency ( NUE ).NO 3−uptake capacity and transcript levels of putative high‐ and low‐affinityNO 3−transporters ( NRT s) were profiled across the lifecycle of dwarf maize ( Zea mays ) plants grown at reduced and adequateNO 3−. Plants showed major changes in high‐affinityNO 3−uptake capacity across the lifecycle, which varied with changing relative growth rates of roots and shoots. Transcript abundances of putative high‐affinity NRT s (predominantly Zm NRT 2.1 and Zm NRT 2.2 ) were correlated with two distinct peaks in high‐affinity rootNO 3−uptake capacity and also N availability. The reduction inNO 3−supply during the lifecycle led to a dramatic increase inNO 3−uptake capacity, which preceded changes in transcript levels of NRT s, suggesting a model with short‐term post‐translational regulation and longer term transcriptional regulation ofNO 3−uptake capacity. These observations offer new insight into the control ofNO 3−uptake by both plant developmental processes and N availability, and identify key control points that may be targeted by future plant improvement programmes to enhance N uptake relative to availability and/or demand.