Rice Overexpressing OsNUC1-S Reveals Differential Gene Expression Leading to Yield Loss Reduction after Salt Stress at the Booting Stage.

Chuthamas Boonchai,Luca Comai,Thanikarn Udomchalothorn,Supachitra Chadchawan,Siriporn Sripinyowanich,Teerapong Buaboocha

doi:10.3390/ijms19123936

Abstract

Rice nucleolin (OsNUC1), consisting of two isoforms, OsNUC1-L and OsNUC1-S, is a multifunctional protein involved in salt-stress tolerance. Here, OsNUC1-S’s function was investigated using transgenic rice lines overexpressing OsNUC1-S. Under non-stress conditions, the transgenic lines showed a lower yield, but higher net photosynthesis rates, stomatal conductance, and transpiration rates than wild type only in the second leaves, while in the flag leaves, these parameters were similar among the lines. However, under salt-stress conditions at the booting stage, the higher yields in transgenic lines were detected. Moreover, the gas exchange parameters of the transgenic lines were higher in both flag and second leaves, suggesting a role for OsNUC1-S overexpression in photosynthesis adaptation under salt-stress conditions. Moreover, the overexpression lines could maintain light-saturation points under salt-stress conditions, while a decrease in the light-saturation point owing to salt stress was found in wild type. Based on a transcriptome comparison between wild type and a transgenic line, after 3 and 9 days of salt stress, the significantly differentially expressed genes were enriched in the metabolic process of nucleic acid and macromolecule, photosynthesis, water transport, and cellular homeostasis processes, leading to the better performance of photosynthetic processes under salt-stress conditions at the booting stage.

Highlights

Rice (Oryza sativa L.) is a staple food and a main source of energy for humans, especially in Asia
Ion toxicity causes changes in plant metabolism, including the photosynthesis processes and energy production [3]. It directly affects photosynthetic components, including chlorophyll a, chlorophyll b, and carotenoids, because salt stress increases enzyme activities involved in chlorophyll degradation, which leads to a decrease in chlorophyll levels [4]
OsNUC1 expression was compared among wild type (WT) and the transgenic lines, when grown in the control and salt stress condition at reproductive stage

Summary

Introduction

Rice (Oryza sativa L.) is a staple food and a main source of energy for humans, especially in Asia. Salinity is a severe abiotic stress worldwide that directly contributes to the economic outcome of agriculturists It negatively affects plants at both physiological and cellular levels. Ion toxicity causes changes in plant metabolism, including the photosynthesis processes and energy production [3] It directly affects photosynthetic components, including chlorophyll a, chlorophyll b, and carotenoids, because salt stress increases enzyme activities involved in chlorophyll degradation, which leads to a decrease in chlorophyll levels [4]. It can induce reactive oxygen species (ROS) production, which can trigger protein and lipid damage [5]. The level of plant injury depends on species, developmental stage, age, and the severity of the salinity

Methods

Results

Conclusion