Physiological and comparative proteomic analysis provides new insights into the effects of shade stress in maize (Zea mays L.)

Abstract

Background: Shade stress, a universal abiotic stress, suppresses plant growth and production seriously. However, little is known regarding the protein regulatory networks under shade stress. To better characterize the proteomic changes of maize leaves under shade stress, 60% shade (S) and supplementary lighting (L) on cloudy daylight from tasseling stage to physiological maturity stage were designed, the ambient sunlight treatment was used as control (CK). Isobaric tag for relative and absolute quantification (iTRAQ) technology was used to determine the proteome profiles in leaves. Results: Shading significantly decreased the SPAD value, net photosynthetic rate, and grain yield. During two experimental years, grain yields of S were reduced by 48 and 47%, and L increased by 6 and 11%, compared to CK. In total, 3958 proteins were identified by iTRAQ, and 2745 proteins were quantified including 349 proteins showed at least 1.2-fold changes in expression levels between treatments and CK. The differentially expressed proteins were classified into photosynthesis, stress defense, energy production, signal transduction, and protein and amino acid metabolism using the Web Gene Ontology Annotation Plot online tool. In addition, these proteins showed significant enrichment of the chloroplasts (58%) and cytosol (21%) for subcellular localization. Conclusions: 60% shade induced the expression of proteins involved in photosynthetic electron transport chain (especially light-harvesting complex) and stress/defense/detoxification. However, the proteins related to calvin cycle, starch and sucrose metabolisms, glycolysis, TCA cycle, and ribosome and protein synthesis were dramatically depressed. Together, our results might help to provide a valuable resource for protein function analysis and also clarify the proteomic and physiological mechanism of maize underlying shade stress.

Effects of solar radiation on root and shoot growth of maize and the quantitative relationship between them

“…In recent years, global solar radiation intensity has been declining as a result of climate change; the amount of solar radiation reaching the surface has decreased by an average of 2.7% per decade over the past 50 yr (Abakumova, Gorbarenko, Nezval, & Shilovteseva, 2008;Che et al, 2005;Stanhill & Cohen, 2001). Some maize (Zea mays L.) growing areas in China receive low solar radiation due to high cloud cover (Cui, Camberato, Jin, & Zhang, 2015;Gao, Liu, Zhao, Liu, & Zhang, 2020). Additionally, the increase in planting density leads to canopy closure and consequently reduces the amount of solar radiation reaching the bottom of the canopy, which is not conducive to biomass accumulation (Enrico et al, 2013;Mao et al, 2014;Purcell, Ball, Reaper, & Vories, 2002).…”

Low Light/Darkness as Stressors of Multifactor-Induced Senescence in Rice Plants

“…Subsequently, the efficient photosynthetic rate under low-light treatments enhances the potential capacity of antioxidant enzymes. Some evidence in the literature has suggested that plants under light shading mediate some of these processes, such as increasing subunits of ferredoxin, cytochrome P450 and PS1 reaction cores, which are accompanied by increases in some metabolites (particularly carbon metabolites), and thus establish equilibrium under shading conditions that result in a low-light response [ 34 ], with no or low substantial impact on yield. Similarly, tolerant rice varieties have been shown to exhibit higher chlorophyll a and b contents and lower chlorophyll a/b ratio than the light-sensitive varieties [ 6 ], in addition to maintaining a higher capacity of antioxidants.…”

“…In a study conducted on maize plants, shading conditions decreased the abundance of sucrose synthases and carbohydrate substances (fructose-bisphosphate aldolase, starch synthase, and isoflavone reductase) initially by inhibiting PSI and dark reactions, thus enhancing light energy utilization by the accumulation of electron-transfer-related proteins and alleviating the detrimental effects of shading on plant physiological processes. An investigation of differentially abundant proteins (DAPs) revealed a significant increase in PSII proteins and the inhibition of starch synthesis and CO 2 fixation, which led to damaged photosynthetic apparatus and consequently reduced biomass and grain yield during late growth stages [ 34 ]. Shading has recently been reported to decrease the grain yield of fragrant rice, which has been alleviated by the exogenous application of γ-amino butyric acid (GABA) to non-protein amino acids [ 44 ].…”

Phosphate fertilizers increase CO2 assimilation and yield of soybean plants in a shaded environment

“…One question we aimed to address was whether the high CO 2 assimilation rates observed in soybean under shading condition is a consequence of the signi cant improvement of the photosynthetic system or the activity of the related reaction process of the Calvin-Benson cycle. Related studies have shown that C3 cycle-related enzymes are notably affected by light intensity [12,14] . As the most abundant enzyme in plants, the proportion of activated Rubisco in C3 plants is about 25% [27,28] , the content may be excessive, so the reduction of Rubisco carboxylation rate can be compensated by rapid activation.…”

“…Photosynthesis is a complex biochemical and biophysical process that comprises photosynthetic pigment synthesis, light energy electron transport, and the Calvin cycle [5,6] , these processes are all affected by the light intensity [7] . Leaf area, chlorophyll content, and antenna pigment-protein under weak light environment improve the light interception and the absorption e ciency [8,9] , but the decrease of light conversion and electron transfer e ciency [10,11] as well as a signi cant decrease in expression level and activity of photosynthetic carbon immobilized enzyme [12][13][14] resulting in the inevitable reduction of photosynthetic capacity under weak light. Increasing nutrients is one of the important ways for crops to improve the use of low light [15] .…”