PHYTOCHROME-INTERACTING FACTOR-LIKE14 and SLENDER RICE1 Interaction Controls Seedling Growth under Salt Stress.

Weiping Mo,Rongcheng Lin,Weijiang Tang,Yanjun Jing,Yanxin Du,Qingyun Bu

doi:10.1104/pp.20.00024

Abstract

Early seedling development and emergence from the soil, which are critical for plant growth and important for crop production, are controlled by internal factors, such as phytohormones, and external factors, such as light and salt. However, little is known about how light and salt signals are integrated with endogenous cues in controlling plant physiological processes. Here, we show that overexpression of rice (Oryza sativa) PHYTOCHROME-INTERACTING FACTOR-LIKE14 (OsPIL14) or loss of function of the DELLA protein SLENDER RICE1 (SLR1) promotes mesocotyl and root growth, specifically in the dark and under salt stress. Furthermore, salt induces OsPIL14 turnover but enhances SLR1 accumulation. OsPIL14 directly binds to the promoter of cell elongation-related genes and regulates their expression. SLR1 physically interacts with OsPIL14 and negatively regulates its function. Our study reveals a mechanism by which the OsPIL14-SLR1 transcriptional module integrates light and gibberellin signals to fine-tune seedling growth under salt stress, enhancing understanding about how crops adapt to saline environments.

Highlights

Seedling development and emergence from the soil are controlled by internal factors, such as phytohormone, and external factors, such as light and salt
Our findings reveal that OsPIL14-SLENDER RICE1 (SLR1) interaction integrates light and GA signals to precisely control seedling growth under salt stress
To study the function of these OsPIL genes, we generated transgenic rice lines overexpressing OsPIL11, OsPIL12, OsPIL14, OsPIL15, and OsPIL16 fused with green (UBQp:OsPIL-GFP) in the japonica cv

Summary

Introduction

Seedling development and emergence from the soil are controlled by internal factors, such as phytohormone, and external factors, such as light and salt. Arabidopsis seedlings undergo skotomorphogenesis with rapid elongation of the hypocotyl and closed cotyledons; upon emergence from the soil, the seedlings photomorphogenesis, a process in which light inhibits hypocotyl elongation but promotes cotyledon opening (Jiao et al, 2007). Correlative evidence reveals that PIFs play essential roles in the integration of light and other signaling pathways, such as gibberellin (GA), ethylene, auxin, brassinosteroid, reactive oxygen species, or temperature (Franklin et al, 2011; Feng et al, 2008; de Lucas et al, 2008; Lee and Thomashow, 2012; Bai et al, 2012; Chen et al, 2013; Zhong et al, 2014; Paik et al, 2017)

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