Abstract

Background

Many transcription factors (TFs), such as those in the basic helix-loop-helix (bHLH) family, are important for regulating plant growth and plant responses to abiotic stress. The expression of OsbHLH035 is induced by drought and salinity. However, its functional role in rice growth, development, and the salt response is still unknown.

Results

The bHLH TF OsbHLH035 is a salt-induced gene that is primarily expressed in germinating seeds and seedlings. Stable expression of GFP-fused OsbHLH035 in rice transgenic plants revealed that this protein is predominantly localized to the nucleus. Osbhlh035 mutants show delayed seed germination, particularly under salt-stress conditions. In parallel, abscisic acid (ABA) contents are over-accumulated, and the expression of the ABA biosynthetic genes OsABA2 and OsAAO3 is upregulated; furthermore, compared with that in wild-type (WT) seedlings, the salt-induced expression of OsABA8ox1, an ABA catabolic gene, in germinating Osbhlh035 mutant seeds is downregulated. Moreover, Osbhlh035 mutant seedlings are unable to recover from salt-stress treatment. Consistently, sodium is over-accumulated in aerial tissues but slightly reduced in terrestrial tissues from Osbhlh035 seedlings after salt treatment. Additionally, the expression of the sodium transporters OsHKT1;3 and 1;5 is reduced in Osbhlh035 aerial and terrestrial tissues, respectively. Furthermore, genetic complementation can restore both the delayed seed germination and the impaired recovery of salt-treated Osbhlh035 seedlings to normal growth.

Conclusion

OsbHLH035 mediates seed germination and seedling recovery after salt stress relief through the ABA-dependent and ABA-independent activation of OsHKT pathways, respectively.

Details

Title
The transcription factor OsbHLH035 mediates seed germination and enables seedling recovery from salt stress through ABA-dependent and ABA-independent pathways, respectively
Author
Hung-Chi, Chen 1 ; Wan-Hsing, Cheng 2 ; Chwan-Yang, Hong 3 ; Yu-Sen, Chang 4 ; Men-Chi Chang 1 

 Department of Agronomy, National Taiwan University, Taipei, Taiwan, Republic of China 
 Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan, Republic of China 
 Department of Agricultural Chemistry, National Taiwan University, Taipei, Taiwan, Republic of China 
 Department of Horticulture and Landscape Architecture, National Taiwan University, Taipei, Taiwan, Republic of China 
Pages
1-17
Publication year
2018
Publication date
Sep 2018
Publisher
Springer Nature B.V.
ISSN
19398425
e-ISSN
19348037
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2101770186
Copyright
Rice is a copyright of Springer, (2018). All Rights Reserved., © 2018. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.