Quantitative proteomic analysis of super soft kernel texture in soft white spring wheat

Authors: AOUN, MERIEM - Oklahoma State University; ORENDAY-ORTIZ, JOSE - Firestone Pacific Foods; BROWN, KITTY - Colorado State University; BROECKLING, COREY - Colorado State University; Morris, Craig; Kiszonas, Alecia

Submitted to: PLOS ONE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/26/2023
Publication Date: 9/7/2023
Citation: Aoun, M., Orenday-Ortiz, J., Brown, K., Broeckling, C., Morris, C.F., Kiszonas, A. 2023. Quantitative proteomic analysis of super soft kernel texture in soft white spring wheat. PLOS ONE. Article e0289784. https://doi.org/10.1371/journal.pone.0289784.
DOI: https://doi.org/10.1371/journal.pone.0289784

Interpretive Summary: Kernel texture or grain hardness is the primary determinant of wheat milling and baking quality. Grain hardness determines wheat end-use products as hard wheat is used for making pan breads, whereas soft wheat is used for making crackers, cookies, cakes, steam breads, and some Asian-style noodles. The puroindoline genes (Pina-D1 and Pinb-D1) at the Hardness (Ha) locus on chromosome arm 5DS are the primary factors controlling grain hardness and distinguishing soft wheat from hard wheat. The presence of puroindoline wild-type genes results in soft texture, whereas the absence or mutation in the puroindoline genes results in harder kernels. Grain hardness is also influenced by various physical and chemical factors including kernel size, vitreousness, protein content, water-soluble pentosans (non-starch polysaccharides), and lipid content. The objective of this study was to investigate differentially abundant proteins (DAPs) between normal soft and super soft kernel texture during kernel development. This investigation will enhance our understanding of the mechanism underlying the super soft phenotype. Based on previous genetic analysis study of super soft kernel texture in BC2SS163 and the current study, TraesCS4B02G091100.1 which encodes for sucrose-phosphate synthase is likely a candidate gene associated with the super soft kernel phenotype in BC2SS163. Functional validation of TraesCS4B02G091100 is worth exploring in future studies.

Technical Abstract: Grain hardness is a key physical determinant which influences wheat end-use quality. Super soft kernel texture is associated with superior milling and baking performance in soft wheat. To understand the mechanism underlying super soft kernel texture, we studied proteomic changes between normal soft and super soft during kernel development. The cultivar ‘Alpowa’, a soft white spring wheat, was crossed to a closely related super soft spring wheat line ‘BC2SS163’ to produce F6 recombinant inbred lines (RILs) via single seed descent. Four normal soft RILs and four super soft RILs along with the parents were selected for proteomic analysis. Alpowa and the normal soft RILs showed hardness indices of 20 to 30, whereas BC2SS163 and the super soft RILs showed hardness indices of -2 to -6. Kernels were collected from normal soft and super soft genotypes at 7 days post anthesis (7 dpa), 14 dpa, 21 dpa, 28 dpa, and maturity and were subject to quantitative proteomic analysis. Throughout kernel development, 175 differentially abundant proteins (DAPs) were identified. Most DAPs were observed at 7 dpa, 14 dpa, and 28 dpa, whereas a single DAP and nine DAPs were identified at 21 dpa and maturity, respectively. Of the 175 DAPs, 32 had higher abundance in normal soft wheat, whereas 143 DAPs had higher abundance in super soft wheat. In this study, 18 DAPs were associated with carbohydrates and five DAPs were associated with lipids. The gene TraesCS4B02G091100.1 on chromosome arm 4BS, which encodes for sucrose-phosphate synthase, was identified as a candidate gene associated with the super soft kernel texture in BC2SS163 as it was within the genomic region of a previously identified quantitative trait locus associated with super soft kernel texture in BC2SS163. The results are useful to understand the mechanism of super soft kernel texture in soft white wheat.