Abstract
Hydrogen peroxide (H2O2) is one of the most abundant reactive oxygen species (ROS), which plays dual roles as a toxic byproduct of cell metabolism and a regulatory signal molecule in plant development and stress response. Populus simonii × Populus nigra is an important cultivated forest species with resistance to cold, drought, insect and disease, and also a key model plant for forest genetic engineering. In this study, H2O2 response in P. simonii × P. nigra leaves was investigated using physiological and proteomics approaches. The seedlings of 50-day-old P. simonii × P. nigra under H2O2 stress exhibited stressful phenotypes, such as increase of in vivo H2O2 content, decrease of photosynthetic rate, elevated osmolytes, antioxidant accumulation, as well as increased activities of several ROS scavenging enzymes. Besides, 81 H2O2-responsive proteins were identified in the poplar leaves. The diverse abundant patterns of these proteins highlight the H2O2-responsive pathways in leaves, including 14-3-3 protein and nucleoside diphosphate kinase (NDPK)-mediated signaling, modulation of thylakoid membrane structure, enhancement of various ROS scavenging pathways, decrease of photosynthesis, dynamics of proteins conformation, and changes in carbohydrate and other metabolisms. This study provides valuable information for understanding H2O2-responsive mechanisms in leaves of P. simonii × P. nigra.
Highlights
Various environmental stresses usually affect reactive oxygen species (ROS) homeostasis in plants, leading to the generation of excess ROS, such as singlet oxygen (1O2), superoxide anion radicals (O2−), hydrogen peroxide (H2O2), and hydroxyl radicals (HO)
Our results indicate that modulation of thylakoid structure, ROS scavenging pathways, photosynthesis, and protein conformation play critical roles in P. simonii × P. nigra leaves in response to H2O2
We found that NDPK1 was reduced in poplar leaves under H2O2 stress (Table 1 and Figure 9A), which was reduced in Arabidopsis leaves in response to 3 mM H2O2 for five days [20]
Summary
Various environmental stresses usually affect reactive oxygen species (ROS) homeostasis in plants, leading to the generation of excess ROS, such as singlet oxygen (1O2), superoxide anion radicals (O2−), hydrogen peroxide (H2O2), and hydroxyl radicals (HO). H2O2 is the most abundant ROS in plant cells during photosynthesis, photorespiration, and respiration processes [1]. Excess H2O2 has obvious oxidative destruction of diverse molecules (e.g., proteins, nucleic acids, carbohydrates, and unsaturated lipids) in plant cells [4], which disturbs cellular activity and causes programmed cell death [2]. H2O2 changes in cells showed as a bell-shaped response with an optimum, depending on the plant species, developmental stages, cell types, and environmental conditions [2,7]
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