Premium
OsPIN9, an auxin efflux carrier, is required for the regulation of rice tiller bud outgrowth by ammonium
Author(s) -
Hou Mengmeng,
Luo Feifei,
Wu Daxia,
Zhang Xuhong,
Lou Manman,
Shen Defeng,
Yan Ming,
Mao Chuanzao,
Fan Xiaorong,
Xu Guohua,
Zhang Yali
Publication year - 2021
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.16901
Subject(s) - auxin , tiller (botany) , ammonium , biology , mutant , oryza sativa , microbiology and biotechnology , biochemistry , botany , chemistry , gene , organic chemistry
Summary The degree of rice tillering is an important agronomic trait that can be markedly affected by nitrogen supply. However, less is known about how nitrogen‐regulated rice tillering is related to polar auxin transport. Compared with nitrate, ammonium induced tiller development and was paralleled with increased 3 H‐indole‐acetic acid (IAA) transport and greater auxin into the junctions. OsPIN9 , an auxin efflux carrier, was selected as the candidate gene involved in ammonium‐regulated tillering based on GeneChip data. Compared with wild‐type plants, ospin9 mutants had fewer tillers, and OsPIN9 overexpression increased the tiller number. Additionally, OsPIN9 was mainly expressed in vascular tissue of the junction and tiller buds, and encoded a membrane‐localised protein. Heterologous expression in Xenopus oocytes and yeast demonstrated that OsPIN9 is a functional auxin efflux transporter. More importantly, its RNA and protein levels were induced by ammonium but not by nitrate, and tiller numbers in mutants did not respond to nitrogen forms. Further advantages, including increased tiller number and grain yield, were observed in overexpression lines grown in the paddy field at a low‐nitrogen rate compared with at a high‐nitrogen rate. Our data revealed that ammonium supply and an auxin efflux transporter co‐ordinately control tiller bud elongation in rice.