Source-sink modifications affect leaf senescence and grain mass in wheat as revealed by proteomic analysis

Abstract

Background The grain yield of cereals is determined by the synergistic interaction between source activity and sink capacity. However, source-sink interactions are far from being fully understood. Therefore, a field experiment was performed in wheat to investigate the responses of flag leaves and grains to sink/source manipulations. Results Half-degraining delayed but partial defoliation enhanced leaf senescence. Sink/source manipulations influenced the content of reactive oxygen species in the flag leaf and the concentration of phytohormones, including cytokinins, indoleacetic 3-acid and jasmonic acid, in the flag leaves (LDef) and grains (GDef) in defoliated plants and flag leaves (LDG) and grain (GDG) in de-grained plants. Isobaric tag for relative and absolute quantitation (iTRAQ)-based quantitative proteomic analysis indicated that at 16 days after manipulation, a total of 97 and 59 differentially expressed proteins (DEPs) from various functional categories were observed in the LDG and LDef groups, respectively, compared with the control, and 115 and 121 DEPs were observed in the GDG and GDef groups, respectively. The gene ontology annotation terms of the DEPs mainly included carbon fixation, hydrogen peroxide catabolic process, chloroplast and cytoplasm, oxidoreductase activity and glutamate synthase activity in the flag leaves of manipulated plants and organonitrogen compound metabolic process, cytoplasm, vacuolar membrane, CoA carboxylase activity, starch synthase activity and nutrient reservoir activity in the grains of manipulated plants. KEGG pathway enrichment analysis revealed that photosynthesis, carbon, nitrogen and pyruvate metabolism and glycolysis/gluconeogenesis were the processes most affected by sink/source manipulations. Sink/source manipulations affected the activities of amylase and proteinases and, ultimately, changed the mass per grain. Conclusions Manipulations to change the sink/source ratio affect hormone levels; hydrolytic enzyme activities; metabolism of carbon, nitrogen and other main compounds; stress resistance; and leaf senescence and thus influence grain mass.

Hormonal endogenous changes in response to the exogenous 6-benzylaminopurine application in pre- and post-harvesting lilium flower stalks

“…Hormones can participate directly in its regulation or can work in an antagonistic way. This view is highly consistent with the findings that certain cultivars under stress conditions trigger premature senescence and penalize plant production (Lv et al, 2020).…”

A Comparison of UAV RGB and Multispectral Imaging in Phenotyping for Stay Green of Wheat Population

“…The grains were mainly kernel length in establishment in the early stage (rapid increase in grain size with little dry matter accumulation). In the rapid senescent period, canopy greenness or vigor decay were fast as the competition became fierce in the middle and late stage (milky ripe stage) due to grains requiring many photosynthates to accumulate solid content until the kernels achieve maximum dry weight and physical maturity [9,11]. For canopy greenness, vigor or green leaf area, they showed a slow decline in the early stage and rapid decline in the middle and late stages during wheat senescence [60].…”

“…Wheat SG changes mainly occur from the anthesis to the maturity stage, followed by stem and leaf greenness fading and spike and grain maturity. However, wheat stay green is a complex biological phenomenon or dynamic quantitative trait, which is affected by multiple environmental factors, complicated genetic mechanisms, diversified senescence patterns, and changes in microscopic biochemical components during late development [9][10][11]. For wheat SG, precision screening and identification are difficult to achieve by traditional phenotyping methods (visual scoring, physiological and biochemical trait measurement, etc.)…”

Improving Grain Yield via Promotion of Kernel Weight in High Yielding Winter Wheat Genotypes

“…We highlight the importance of coordinating and optimizing these characteristics to balance the sink and source for achieving a high yield. As a result, all photosynthetic canopy organs must be collectively considered, and the photosynthesis rate of the flag leaves and non-leaf organs should be evaluated [ 48 , 51 , 99 ]. In this manner, the photosynthetic capacity of the entire wheat plant and the whole plant population can be fully exploited to improve the photosynthesis rate.…”

“…Wheat yield-related traits are all complex agronomic and physiological traits [ 47 ], integration of traits such as the source–sink balance must be considered to achieve successful grain yield gain [ 48 , 49 ]. Sink size in developing yield organs is determined by the number of spikes per unit area, grains per spike, sink size per grain, and thousand-grain weight.…”