Comparative Proteome Analysis of Wheat Flag Leaves and Developing Grains Under Water Deficit

Abstract

In this study, we performed the first comparative proteomic analysis of wheat flag leaves and developing grains in response to drought stress. Drought stress caused a significant decrease in several important physiological and biochemical parameters and grain yield traits, particularly those related to photosynthesis and starch biosynthesis. In contrast, some key indicators related to drought stress were significantly increased, including malondialdehyde, soluble sugar, proline, glycine betaine, abscisic acid content, and peroxidase activity. Two-dimensional difference gel electrophoresis (2D-DIGE) identified 87 and 132 differentially accumulated protein (DAP) spots representing 66 and 105 unique proteins following exposure to drought stress in flag leaves and developing grains, respectively. The proteomes of the two organs varied markedly, and most DAPS were related to the oxidative stress response, photosynthesis and energy metabolism, and starch biosynthesis. In particular, DAPs in flag leaves mainly participated in photosynthesis while those in developing grains were primarily involved in carbon metabolism and the drought stress response. Western blotting and quantitative real-time polymerase chain reaction (qRT-PCR) further validated some key DAPs such as rubisco large subunit (RBSCL), ADP glucose pyrophosphorylase (AGPase), chaperonin 60 subunit alpha (CPN-60 alpha) and oxalate oxidase 2 (OxO 2). The potential functions of the identified DAPs revealed that a complex network synergistically regulates drought resistance during grain development. Our results from proteome perspective provide new insight into the molecular regulatory mechanisms used by different wheat organs to respond to drought stress.

Effects of water deficit and different nitrogen fertilizer treatments on the quality of wheat for Chinese fresh white noodles and steamed bread and the composition of storage proteins

“…Under water deficit, the soil moisture content measured in the soil layers from 0–100 cm at the grain flowering stage and 0–160 cm at the mature stage in the treatment group was significantly lower than that of the control group, particularly in soil layers from 0–40 cm (Fig. S2 in the supporting information), indicating a mild to severe drought stress during grain development based on the grade of agricultural drought (GB/T 32136–2015) …”

“…Our results also showed that water deficit significantly increased the protein content and farinograph parameters in both Zhongmai175 and Jimai 22 (Table ). It is generally accepted that carbon metabolism is more sensitive to drought stress than nitrogen metabolism, resulting in a decrease in starch biosynthesis and an increase in protein content . However, the effects of drought stress on noodle and steamed bread qualities are still not clear.…”

“…S2 in the supporting information), indicating a mild to severe drought stress during grain development based on the grade of agricultural drought (GB/T 32136-2015). 42 Water deficit treatment caused significant changes in the main agronomic traits and yield performance in both Zhongmai 175 and Jimai 22 (Table S1 in the supporting information). Plant height, spike number, grain number per spike, and grain yield under water deficit were significantly decreased in both cultivars.…”

“…It is generally accepted that carbon metabolism is more sensitive to drought stress than nitrogen metabolism, resulting in a decrease in starch biosynthesis and an increase in protein content. 24,42 However, the effects of drought stress on noodle and steamed bread qualities are still not clear. Generally, soft grain, high whiteness, medium protein content, and medium to high gluten strength are desirable for Chinese noodles, 4,5,8,9 while wheat cultivars with good quality for steamed bread have medium flour protein and moderately strong dough strength.…”

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

“…Under global climate change and climate warming, the frequency and duration of extreme drought events is increasing faster than previously predicted [8]. Drought stress disrupts cell homeostasis and generally induces a number of morphological, physiological, and biochemical changes in all plant organs [9], particularly affecting leaf photosynthesis and transfer of stored carbohydrates [10]. Under drought stress, plants typically close the stomata, reducing evaporative treatment resulted in a significant decrease in RWC, chlorophyll content and Pn, whereas the high-N fertilizer and combined treatments showed a significant increase in chlorophyll content and Pn.…”