Title
OsCHX14 is Involved in the K+ Homeostasis in Rice (Oryza sativa) Flowers
Author
Chen, Y.
Miller, A.J.
Luo, B.
Wang, M.
Zhu, Z.
Ouwerkerk, P.B.F.
Publication year
2016
Abstract
Previously we showed in the osjar1 mutants that the lodicule senescence which controls the closing of rice flowers was delayed. This resulted in florets staying open longer when compared with the wild type. The gene OsJAR1 is silenced in osjar1 mutants and is a key member of the jasmonic acid (JA) signaling pathway. We found that K concentrations in lodicules and flowers of osjar1-2 were significantly elevated compared to the wild type, indicating that K+ homeostasis may play a role in regulating the closure of rice flowers. The cation/H+ exchanger (CHX) family from rice was screened for potential K+ transporters involved as many members of this family in Arabidopsis were exclusively or preferentially expressed in flowers. Expression profiling confirmed that among 17 CHX genes in rice, OsCHX14 was the only member that showed an expression polymorphism, not only in osjar1 mutants but also in RNAi lines of OsCOI1, another key member of the JA signaling pathway. This suggests that the expression of OsCHX14 is regulated by the JA-signaling pathway. GFP-tagged OsCHX14 protein was preferentially localized to the endoplasmic reticulum. Promoter-GUS analysis of transgenic rice revealed that OsCHX14 is mainly expressed in lodicules and the region close by throughout the flowering process. Characterization in yeast and Xenopus laevis oocytes verified that OsCHX14 is able to transport K+, Rb+ and Cs+ in vivo. Our data suggest that OsCHX14 may play an important role in K+ homeostasis during flowering in rice.
Subject
Life
MHR - Metabolic Health Research
ELSS - Earth, Life and Social Sciences
Biomedical Innovation
Biology
Healthy Living
CHX transporter
Flower
Jasmonate
Lodicule
Potassium
Rice
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DOI
https://doi.org/10.1093/pcp/pcw088
TNO identifier
564740
Source
Plant and Cell Physiology, 57 (7), 1530-1543
Document type
article