integrated approach to understand the functioning of

1 downloads 0 Views 3MB Size Report
Nov 8, 2018 - Classification and Polymorphism of Wheat Grain Proteins ... SDS-insoluble polymers/total polymers ratio is Strongly correlated with the ... Variation of the content of polymeric proteins conjugated to glutathione (PPSSG) for.
INTEGRATED APPROACH TO UNDERSTAND THE FUNCTIONING OF WHEAT QUALITY COMPONENTS AND THEIR INTERACTION WITH ENVIRONMENTS

LARBI RHAZI & THIERRY AUSSENAC EA 7519 TRANSFORMATIONS & AGRO-RESSOURCES

ICC International Conference GRAINS FOR WELLBEING Taipei, Chinese Taipei 5 - 8 November 2018

INTEGRATED APPROACH TO UNDERSTAND THE FUNCTIONING OF WHEAT QUALITY COMPONENTS AND THEIR INTERACTION WITH ENVIRONMENTS Introduction

Hoseney and Rogers 1990

GRAINS FOR WELLBEING Taipei, Chinese Taipei; 5 - 8 November 2018

MOLECULAR WEIGHT DISTRIBUTION (MWD) OF WHEAT STORAGE PROTEINS Classification and Polymorphism of Wheat Grain Proteins

GRAINS FOR WELLBEING Taipei, Chinese Taipei; 5 - 8 November 2018

MOLECULAR WEIGHT DISTRIBUTION (MWD) OF WHEAT STORAGE PROTEINS Gliadin to Glutenin Ratio: A structural model for wheat gluten

Monomeric Gliadins : Viscosity, Extensibility Lamacchia et al., 2014

Polymeric Glutenins : Tenacity, Elasticity

MOLECULAR WEIGHT DISTRIBUTION (MWD) OF WHEAT STORAGE PROTEINS Analytical methods

SEC-HPLC

The amount of glutenin aggregates, Monomer to polymer ratio, Soluble to insoluble ratio,

The bread-making quality

MOLECULAR WEIGHT DISTRIBUTION (MWD) OF WHEAT STORAGE PROTEINS Distribution of Glutenin subunits Lab-On-Chip

RP-HPLC

Quantitative and qualitative analysis: HMW, HMW-GS/HMW-GS HMW-GS/LMW-GS Translocations

MOLECULAR WEIGHT DISTRIBUTION (MWD) OF PROTEIN AGGREGATES Size Distribution of Polymeric Proteins Size Distribution of Polymeric Proteins

Glutenin aggregates: Molecular weight, molecular size, And conformation

Technological parameters (W, P, L …)

Asymmetrical flow field-flow fractionation (A4F) + MALLS

MOLECULAR WEIGHT DISTRIBUTION (MWD) OF PROTEIN AGGREGATES Size Distribution of Polymeric Proteins

Glutenin subunits (i.e. HMW-GS, LMW-GS, A-FFFF / MALLS / RI /UV and HMW-GS x and y type) are unequally Hierarchical arrangement of HMW-GS distributed within polymers and LMW-GS in relation to their intrinsic contribution to polymer formation Kasarda 1999

(Aussenac T., Rhazi L. 2018. J. Exp. Bot. in press.)

GRAINS FOR WELLBEING Taipei, Chinese Taipei; 5 - 8 November 2018

ACCUMULATION OF PROLAMINS IN DEVELOPING WHEAT GRAINS Accumulation of total polymers, SDS-soluble and SDS-insoluble polymers (●) Soissons and, (O) Thésée.

Open symbols = Thésée, closed symbols = Soissons. (▲, Δ)SDS-soluble polymers; (●,O) SDS-insoluble polymers.

The UPP accumulation phase coincides very strongly with the grain desiccation phase SDS-insoluble polymers/total polymers ratio is Strongly correlated with the HMW-GS/LMW-GS ratio

ACCUMULATION OF PROLAMINS IN DEVELOPING WHEAT GRAINS Unextractable Polymeric Protein (UPP) accumulation

The UPP accumulation phase coincides with the oxidation of protein SH

The existence of a late mechanism of storage protein oxidation (i.e. formation of SS bonds from SH groups)

Change in sulfhydryl status of wheat proteins during grain development and maturation

IMPACTS OF ENVIRONMENTAL FACTORS ON MWD OF PROLAMINS The impact of environmental components on the molecular weight distribution of proteins 130 Soft wheat genotypes grown in 3 different environments/2 cropping seasons

Parameters

Minimum

Maximum

Mean

value

value

value

2G/2R

2E/2R

Total proteins(1)

8.700

15.100

11.187

11.411***

271.577***

Total polymers(1)

2.785

5.755

4.016

11.104***

187.462***

Polymer/monomer

0.321

0.700

0.561

14.845***

72.611***

Polymer Mn(2)

0.730 x106

9.609 x106

0.972 x106

1.068NS

4.383***

Polymer Mw(2)

1.142 x106

22.970 x106

7.640 x106

3.370***

38.974***

Variations: Unextracatble Polymeric Proteins (UPP)/ TP ratio, Extractable Proteins/TP ratio, UPP/EP and distribution of glutenin subunits The impact of environmental components on the molecular weight distribution of the prolamins is significantly greater than that of genetic components

IMPACTS OF ENVIRONMENTAL FACTORS ON MWD OF PROLAMINS Glutathione disulfide-dependent protection of protein thiol groups during desiccation

DH, Dehydration steps. GSH, reduced glutathione; GSSG, glutathione disulfide; GR, glutathione reductase.

IMPACTS OF ENVIRONMENTAL FACTORS ON MWD OF PROLAMINS Changes in PP and PP-S-S-G content during the grain development

Open symbols = cv. Soissons Closed symbols = cv. Thésée.

The formation of coincide with the desiccation phase

The great majority of PSSG is present in the grain in the form of PP-S-S-G (≈85%).

PSSG grain

IMPACTS OF ENVIRONMENTAL FACTORS ON MWD OF PROLAMINS Accumulation of PP and PP-S-S-G: correlations The relationship between the content of high aggregated polymeric proteins (PP with Mw>2 106 g.mol-1) And the content of polymeric proteins conjugated to glutathione (PPSSG)

GSH plays a crucial role in controlling the MWD of the polymeric proteins

IMPACTS OF ENVIRONMENTAL FACTORS ON MWD OF PROLAMINS Accumulation of PP-S-S-G: Genetic impact Glutathione conjugation with polymeric proteins during the grain development results in drastic changes of the cellular redox status

Variation of the content of polymeric proteins conjugated to glutathione (PPSSG) for 130 cultivars

Conclusions Glutenins are largely under the control of protein polymorphism (nature and relative abundance of LMW-GS and HMW-GS Glutenins are largely under the control of the conditions of development and maturation of the grains. Significant work needs to be done to better understand the structure of protein assemblies of technological interest (UPP or GMP). Understand the mechanisms that govern the formation of these polymers and/or protein aggregates in wheat grains during the final stages of their development The important role of cellular redox status It is also important to integrate the methods discussed during this presentation in the varietal stability studies GRAINS FOR WELLBEING Taipei, Chinese Taipei; 5 - 8 November 2018

Thank you for your attention!

GRAINS FOR WELLBEING Taipei, Chinese Taipei; 5 - 8 November 2018