AUTHOR=Li Tianya , Liao Kai , Xu Xiaofeng , Gao Yue , Wang Ziyuan , Zhu Xiaofeng , Jia Baolei , Xuan Yuanhu 

TITLE=Wheat Ammonium Transporter (AMT) Gene Family: Diversity and Possible Role in Host–Pathogen Interaction with Stem Rust

JOURNAL=Frontiers in Plant Science

VOLUME=8

YEAR=2017

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2017.01637

DOI=10.3389/fpls.2017.01637

ISSN=1664-462X

ABSTRACT=<p>Ammonium transporter (AMT) proteins have been reported in many plants, but no comprehensive analysis was performed in wheat. In this study, we identified 23 AMT members (hereafter TaAMTs) using a protein homology search in wheat genome. Tissue-specific expression analysis showed that <italic>TaAMT1;1a, TaAMT1;1b</italic>, and <italic>TaAMT1;3a</italic> were relatively more highly expressed in comparison with other <italic>TaAMTs</italic>. TaAMT1;1a, TaAMT1;1b, and TaAMT1;3a-GFP were localized in the plasma membrane in tobacco leaves, and <italic>TaAMT1;1a, TaAMT1;1b</italic>, and <italic>TaAMT1;3a</italic> successfully complemented a yeast 31019b strain in which ammonium uptake was deficient. In addition, the expression of <italic>TaAMT1;1b</italic> in an <italic>Arabidopsis AMT</italic> quadruple mutant (<italic>qko</italic>) successfully restored <inline-formula><mml:math id="M1" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msubsup><mml:mi mathvariant="normal" mathcolor="black">NH</mml:mi><mml:mi mathvariant="normal" mathcolor="black">4</mml:mi><mml:mn mathvariant="normal" mathcolor="black">+</mml:mn></mml:msubsup></mml:math></inline-formula> uptake ability. Resupply of <inline-formula><mml:math id="M2" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msubsup><mml:mi mathvariant="normal" mathcolor="black">NH</mml:mi><mml:mi mathvariant="normal" mathcolor="black">4</mml:mi><mml:mn mathvariant="normal" mathcolor="black">+</mml:mn></mml:msubsup></mml:math></inline-formula> rapidly increased cellular <inline-formula><mml:math id="M3" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msubsup><mml:mi mathvariant="normal" mathcolor="black">NH</mml:mi><mml:mi mathvariant="normal" mathcolor="black">4</mml:mi><mml:mn mathvariant="normal" mathcolor="black">+</mml:mn></mml:msubsup></mml:math></inline-formula> contents and suppressed expression of <italic>TaAMT1;3a</italic>, but not of <italic>TaAMT;1;1a</italic> and <italic>TaAMT1;1b</italic> expressions. Expression of <italic>TaAMT1;1a, TaAMT1;1b</italic>, and <italic>TaAMT1;3a</italic> was not changed in leaves after <inline-formula><mml:math id="M4" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msubsup><mml:mi mathvariant="normal" mathcolor="black">NH</mml:mi><mml:mi mathvariant="normal" mathcolor="black">4</mml:mi><mml:mn mathvariant="normal" mathcolor="black">+</mml:mn></mml:msubsup></mml:math></inline-formula> resupply. In contrast, nitrogen (N) deprivation induced <italic>TaAMT1;1a, TaAMT1;1b</italic>, and <italic>TaAMT1;3a</italic> gene expressions in the roots and leaves. Expression analysis in the leaves of the stem rust-susceptible wheat line “Little Club” and the rust-tolerant strain “Mini 2761” revealed that <italic>TaAMT1;1a, TaAMT1;1b</italic>, and <italic>TaAMT1;3a</italic> were specifically induced in the former but not in the latter. Rust-susceptible wheat plants grown under N-free conditions exhibited a lower disease index than plants grown with <inline-formula><mml:math id="M5" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msubsup><mml:mi mathvariant="normal" mathcolor="black">NH</mml:mi><mml:mi mathvariant="normal" mathcolor="black">4</mml:mi><mml:mn mathvariant="normal" mathcolor="black">+</mml:mn></mml:msubsup></mml:math></inline-formula> as the sole N source in the medium after infection with <italic>Puccinia graminis</italic> f. sp. <italic>tritici</italic>, suggesting that <inline-formula><mml:math id="M6" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msubsup><mml:mi mathvariant="normal" mathcolor="black">NH</mml:mi><mml:mi mathvariant="normal" mathcolor="black">4</mml:mi><mml:mn mathvariant="normal" mathcolor="black">+</mml:mn></mml:msubsup></mml:math></inline-formula> and its transport may facilitate the infection of wheat stem rust disease. Our findings may be important for understanding the potential function <italic>TaAMTs</italic> in wheat plants.</p>