Effects of Independent and Combined Water-Deficit and High-Nitrogen Treatments on Flag Leaf Proteomes during Wheat Grain Development.

Dong Zhu,Zhimin Wang,Yueming Yan,Xing Yan,Zhen Zhang,Gengrui Zhu

doi:10.3390/ijms21062098

Abstract

We present the first comprehensive proteome analysis of wheat flag leaves under water-deficit, high-nitrogen (N) fertilization, and combined treatments during grain development in the field. Physiological and agronomic trait analyses showed that leaf relative water content, total chlorophyll content, photosynthetic efficiency, and grain weight and yield were significantly reduced under water-deficit conditions, but dramatically enhanced under high-N fertilization and moderately promoted under the combined treatment. Two-dimensional electrophoresis detected 72 differentially accumulated protein (DAP) spots representing 65 unique proteins, primarily involved in photosynthesis, signal transduction, carbohydrate metabolism, redox homeostasis, stress defense, and energy metabolism. DAPs associated with photosynthesis and protein folding showed significant downregulation and upregulation in response to water-deficit and high-N treatments, respectively. The combined treatment caused a moderate upregulation of DAPs related to photosynthesis and energy and carbohydrate metabolism, suggesting that high-N fertilization can alleviate losses in yield caused by water-deficit conditions by enhancing leaf photosynthesis and grain storage compound synthesis.

Highlights

Wheat is a major grain crop cultivated worldwide, with over 600 million tons harvested annually
Treatment resulted in a significant decrease in relative water content (RWC), chlorophyll content and photosynthesis rate (Pn), whereas the high-N fertilizer and combined treatments showed a significant increase in chlorophyll content and Pn
We identified several upregulated differentially accumulated protein (DAP) associated with ATP synthesis and NAD(P)H production in the high-N treatment, including ATP synthase, glyceraldehyde 3-phosphate dehydrogenase (GAPDH), TPI, FBA, 6-PGD, and aconitase

Summary

Introduction

Wheat is a major grain crop cultivated worldwide, with over 600 million tons harvested annually. It is a staple food for humans, providing essential amino acids, minerals and vitamins, and beneficial phytochemicals and dietary fiber to human diets [1]. Concerns for food security, meaning the sufficient production and availability of crops like wheat, are rising as the global climate changes and the human population increases [2]. Plants typically close the stomata, reducing evaporative water loss and decreasing stomatal conductance of carbon dioxide (CO2), thereby reducing CO2 levels and causing a decline in photosynthetic carbon assimilation and subsequent reduction in crop yield [11,12]. A global cereal (maize, rice, and wheat) loss of 1820 million Mg was caused by drought and extreme heat from 1964 to 2007 [5]

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