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A node‐localized transporter Os ZIP 3 is responsible for the preferential distribution of Zn to developing tissues in rice
Author(s) -
Sasaki Akimasa,
Yamaji Naoki,
MitaniUeno Namiki,
Kashino Miho,
Ma Jian Feng
Publication year - 2015
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.13005
Subject(s) - xylem , vascular bundle , oryza sativa , meristem , parenchyma , shoot , vascular tissue , biology , microbiology and biotechnology , immunostaining , transpiration , gene knockdown , botany , gene , biochemistry , immunohistochemistry , photosynthesis , immunology
Summary Developing tissues such as meristem with low transpiration require high Zn levels for their active growth, but the molecular mechanisms underlying the preferential distribution to these tissues are poorly understood. We found that a member of the ZIP ( ZRT , IRT ‐like protein), Os ZIP 3, showed high expression in the nodes of rice ( Oryza sativa ). Immunostaining revealed that Os ZIP 3 was localized at the xylem intervening parenchyma cells and xylem transfer cells of the enlarged vascular bundle in both basal and upper nodes. Neither Os ZIP 3 gene expression nor encoded protein was affected by either deficiency or toxic levels of Zn. Knockdown of Os ZIP 3 resulted in significantly reduced Zn levels in the shoot basal region containing the shoot meristem and elongating zone, but increased Zn levels in the transpiration flow. A short‐term experiment with the 67 Zn stable isotope showed that more Zn was distributed to the lower leaves, but less to the shoot elongating zone and nodes in the knockdown lines compared with the wild‐type rice at both the vegetative and reproductive growth stages. Taken together, Os ZIP 3 located in the node is responsible for unloading Zn from the xylem of enlarged vascular bundles, which is the first step for preferential distribution of Zn to the developing tissues in rice.