AUTHOR=Zou Xiaoyan , Huang Rui , Wang Linjie , Wang Guihua , Miao Ye , Rao Idupulapati , Liu Guodao , Chen Zhijian 

TITLE=SgNramp1, a plasma membrane-localized transporter, involves in manganese uptake in Stylosanthes guianensis

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.1027551

DOI=10.3389/fpls.2022.1027551

ISSN=1664-462X

ABSTRACT=<p>Transporters belonging to the natural resistance-associated macrophage protein (Nramp) family play important roles in metal uptake and homeostasis. Although Nramp members have been functionally characterized in plants, the role of Nramp in the important tropical forage legume <italic>Stylosanthes guianensis</italic> (stylo) is largely unknown. This study aimed to determine the responses of <italic>Nramp</italic> genes to metal stresses and investigate its metal transport activity in stylo. Five <italic>SgNramp</italic> genes were identified from stylo. Expression analysis showed that <italic>SgNramp</italic> genes exhibited tissue preferential expressions and diverse responses to metal stresses, especially for manganese (Mn), suggesting the involvement of <italic>SgNramps</italic> in the response of stylo to metal stresses. Of the five <italic>SgNramps</italic>, <italic>SgNramp1</italic> displayed the highest expression in stylo roots. A close correlation between <italic>SgNramp1</italic> expression and root Mn concentration was observed among nine stylo cultivars under Mn limited condition. The higher expression of <italic>SgNramp1</italic> was correlated with a high Mn uptake in stylo. Subsequent subcellular localization analysis showed that SgNramp1 was localized to the plasma membrane. Furthermore, heterologous expression of <italic>SgNramp1</italic> complemented the phenotype of the Mn uptake-defective yeast (<italic>Saccharomyces cerevisiae</italic>) mutant Δ<italic>smf1</italic>. Mn concentration in the yeast cells expressing <italic>SgNramp1</italic> was higher than that of the empty vector control, suggesting the transport activity of SgNramp1 for Mn in yeast. Taken together, this study reveals that SgNramp1 is a plasma membrane–localized transporter responsible for Mn uptake in stylo.</p>