Low Light Increases the Abundance of Light Reaction Proteins: Proteomics Analysis of Maize (Zea mays L.) Grown at High Planting Density

Abstract

Maize (Zea mays L.) is usually planted at high density, so most of its leaves grow in low light. Certain morphological and physiological traits improve leaf photosynthetic capacity under low light, but how light absorption, transmission, and transport respond at the proteomic level remains unclear. Here, we used tandem mass tag (TMT) quantitative proteomics to investigate maize photosynthesis-related proteins under low light due to dense planting, finding increased levels of proteins related to photosystem II (PSII), PSI, and cytochrome b6f. These increases likely promote intersystem electron transport and increased PSI end electron acceptor abundance. OJIP transient curves revealed increases in some fluorescence parameters under low light: quantum yield for electron transport (φEo), probability that an electron moves beyond the primary acceptor QA− (ψo), efficiency/probability of electron transfer from intersystem electron carriers to reduction end electron acceptors at the PSI acceptor side (δRo), quantum yield for reduction of end electron acceptors at the PSI acceptor side (φRo), and overall performance up to the PSI end electron acceptors (PItotal). Thus, densely planted maize shows elevated light utilization through increased electron transport efficiency, which promotes coordination between PSII and PSI, as reflected by higher apparent quantum efficiency (AQE), lower light compensation point (LCP), and lower dark respiration rate (Rd).

Exogenously Applied Proline Enhances Morph-Physiological Responses and Yield of Drought-Stressed Maize Plants Grown Under Different Irrigation Systems

“…Water stress further decreased the values of the physiological parameters in maize seedlings. This was evident by the disruption of plant photosynthetic potential, possibly due to the stomatal closure and/or metabolic destruction, such as the impairment of photosystem 1 (PSI) and photosystem II (PSII), which are chlorophyll-binding protein complexes ( Ibrahim et al, 2019 ; Zheng et al, 2022 ). Furthermore, water stress increases the generation of reactive oxygen species (ROS), resulting in oxidative damage to plants and degradation of chlorophyll pigments ( Hasanuzzaman et al, 2020 ; Mansoor et al, 2022 ).…”

Sunflower Leaf Structure Affects Chlorophyll a Fluorescence Induction Kinetics In Vivo

“…Many environmental stressors decrease the electron transport activity of PSII in vivo, including high light, salt stress, and drought [ 28 , 29 , 30 ]. However, leaf structure also changes to some extent under environmental stress, including cell miniaturization, and columnar cells are no longer evident [ 31 ].…”

Maize (Zea mays L.) planted at higher density utilizes dynamic light more efficiently

“…This study was conducted simultaneously with a study of the acclimation of photosystems to planting density in maize (Zheng et al, 2022) at the farm of Shandong Agricultural University Experimental (36°10′19″ N, 117°9′03″ E) in Shandong, China, during the 2017 growing season. Climate and nutrition informations of the experimental site were listed in previous report (Zheng et al, 2022). ZD958, a high-yielding and density-tolerant variety grown extensively in the North China Plain, was used in this work.…”

“…We re-analyzed the proteomic data in Zheng et al (2022). Proteins were extracted from frozen leaves with three biological replicates, and labelled using a TMT 10-plex Isobaric Label Reagent Set following the manufacturer's instructions (Supporting Information: Table S1).…”

“…To reveal the molecular mechanisms shaping the photosynthetic response to dynamic light environments, we re-analyzed the proteomic data in Zheng et al (2022), a study that was conducted simultaneously with present study. A TMT-based quantitative proteomics approach was undertaken to analyze protein abundance in maize leaves.…”