Spatial distribution of proteins and metabolites in developing wheat grain and their differential regulatory response during the grain filling process

Abstract

SUMMARY Grain filling and grain development are essential biological processes in the plant’s life cycle, eventually contributing to the final seed yield and quality in all cereal crops. Studies of how the different wheat (Triticum aestivum L.) grain components contribute to the overall development of the seed are very scarce. We performed a proteomics and metabolomics analysis in four different developing components of the wheat grain (seed coat, embryo, endosperm, and cavity fluid) to characterize molecular processes during early and late grain development. In‐gel shotgun proteomics analysis at 12, 15, 20, and 26 days after anthesis (DAA) revealed 15 484 identified and quantified proteins, out of which 410 differentially expressed proteins were identified in the seed coat, 815 in the embryo, 372 in the endosperm, and 492 in the cavity fluid. The abundance of selected protein candidates revealed spatially and temporally resolved protein functions associated with development and grain filling. Multiple wheat protein isoforms involved in starch synthesis such as sucrose synthases, starch phosphorylase, granule‐bound and soluble starch synthase, pyruvate phosphate dikinase, 14‐3‐3 proteins as well as sugar precursors undergo a major tissue‐dependent change in abundance during wheat grain development suggesting an intimate interplay of starch biosynthesis control. Different isoforms of the protein disulfide isomerase family as well as glutamine levels, both involved in the glutenin macropolymer pattern, showed distinct spatial and temporal abundance, revealing their specific role as indicators of wheat gluten quality. Proteins binned into the functional category of cell growth/division and protein synthesis/degradation were more abundant in the early stages (12 and 15 DAA). At the metabolome level all tissues and especially the cavity fluid showed highly distinct metabolite profiles. The tissue‐specific data are integrated with biochemical networks to generate a comprehensive map of molecular processes during grain filling and developmental processes.

Genotype-Dependent Effect of Silencing of TaCKX1 and TaCKX2 on Phytohormone Crosstalk and Yield-Related Traits in Wheat

“…The object of our research is the middle part of the 7 DAP spike of wheat. This is the early developmental stage, named the cellularization stage, which lasts up to 10 days [ 34 ], and is the middle of the cell division or cell expansion stage [ 35 , 36 ] or the late milk stage [ 31 ]. This stage was characterized by a high level of expression of tested TaCKX1 and TaCKX2 genes in wheat [ 27 ] and their orthologs in barley [ 37 ], and their silencing at this stage corresponded to yield-related traits [ 7 , 8 , 15 , 38 ].…”

Mining the Wheat Grain Proteome

“…Using transcriptomics and iTRAQ-labelling proteomics to probe the early stages of wheat grain development, Yang and colleagues quantified and identified 85,000 genes and 7500 proteins [ 7 ]. Zhang and colleagues used deep proteome and metabolome analyses to shed light on the wheat grain filling process, where they dissected grains into seed coat, embryo, endosperm, and cavity fluid during major developmental stages to reveal the dynamic accumulation patterns of molecules over space and time [ 8 ].…”

“…Most popular LC systems in proteomics apply reverse phase (RP) conditions which separate molecules based on their hydrophobicity and retention time (RT). RPLC–MS not only helps separate compounds bearing identical m / z that cannot be differentiated by MS alone, but also allows for the detection of low-abundance molecules by separating them from higher abundance ones [ 8 ]. Shotgun bottom-up or peptide-centric proteomics is the most common gel-free approach in which whole protein samples are digested into peptides prior to LC–MS/MS analysis.…”

TMT-Based Quantitative Proteomic Analysis Reveals the Physiological Regulatory Networks of Embryo Dehydration Protection in Lotus (Nelumbo nucifera)

“…The proteomics study of rice grains during development found that proteins involved in glycolysis and TCA cycle accumulated at a high level at the end of grain maturity (Lee and Koh, 2011). In wheat seeds, glycolysis and starch synthesis was significantly enhanced at the late stage of grain filling, which provided much energy for grain maturity (Zhang N. et al, 2015;Zhang et al, 2021). In this study, 16 DEPs in lotus embryo involved in the glycolysis pathway, of which 7 proteins (fructokinase, pyruvate decarboxylase, fructose-bisphosphate aldolase, etc.)…”