Quality Effects Of H5-Shumai 126 Near Isogenic Lines With Different High-Molecular-weight Glutenin Subunits

High-molecular-weight-glutenin subunits(HMW-GS)are one of the important storage proteins in wheat endosperms.The composition and the number of HMW-GS expressed in wheat background had important effects on wheat processing quality.In our previous study,we obtained two set of near-isogenic lines(NILs)with different HMWGS compositions and numbers by crossing wheat line H5 with all the HMW-GS deleted(HMW-GS: N,N,N,N represent null allele)with an excellent wheat Shumai 126(HMW-GS: N,7+ 9,2 +12).The names and the HMW-GS compositions in these NILs were A1(N,N,N),B1(N,7+9,N),C1(N,N,2+12),D1(N,7+ 9,2 +12),A2(N,N,N),B2(N,7+9,N),C2(N,N,2+12),and D2(N,7+9,2+12),respectively.To investigate the effects of HMW-GS compositions and numbers on wheat processing quality and finally product quality,we planted the two sets of NILs in the Wenjiang and Chongzhou farms in two consecutive years(2021 and 2022)and harvested their seeds.The contents of gluten proteins(including HMW-GS,low-molecular-weight glutenin subunit [(LMWGS),and ω-,α/β-,and γ-gliadins)],and gluten macropolymers [including SDSextractable protein ploymers(EPP)and SDS-unextractable protein ploymers(UPP)],solvent retention capacity(SRC),starch gelatinization parameters,processing qualities,and the quality of bread and biscuits were analyzed.The main results were as follows:1.In terms of contents and proportion of gluten proteins,the ω-,α/β-and γ-gliadin and total gliadin(Gliadin)increased with the decrease of HMW-GS numbers in each set of near-isogenic lines.The average contents of ω-,α/β-,γ-gliadin and total gliadin in A1-D1 lines were 68.56.51 ～ 5115.76,9969.52 ～14467.11,10342.06 ～13302.66 and25427.34 ～34626.27 m AU*min,and A2-D2 lines were 4550.79 ～7416.99,10177.56 ～15068.23,9765.05 ～13385.47 and 24493.40 ～35870.69 m AU*min,respectively.However,there is no obvious law for the proportion of ω-,α/β-and γ-gliadin to total gliadin with the increase or decrease of the HMW-GS numbers among near-isogenic lines.The HMW-GS content and its proportion in glutenin,and the contents of LMWGS,glutenin,and UPP(insoluble glutenin polymer)and the ratio of UPP [UPP%=UPP×100 /(UPP+EPP)] and HMW-GS/LMW-GS all tended to decrease with the decrease of HMW-GS numbers.The average values of four environments in the two sets of near isogenic lines in these seven indexes for A1 to D1 lines were ranged from238.92 to 7775.98 m AU*min,3.72 to 34.96%,6147.85 to 14467.32 m AU*min,6386.77 to 22243.30 m AU*min,1169.09 to 6829.22 m AU*min,4.89 to 29.69%,and 0.04 to0.54,respectively,for A1 to D1 lines,and 255.02 to 7882.74 m AU*min,3.78 to 36.37%,6461.46 to 13801.85 m AU*min,6716.48 to 21684.59 m AU*min,1149.82 to 6964.26 m AU*min,5.21 to 31.21,and 0.04 to 0.57,respectively,for A2 to D2 lines.However,the EPP content,the proportion of LMW-GS to glutenin(LMW-GS/glutenin)and gliadin to glutenin(gliadin/glutenin)increased with the decrease of the HMW-GS numbers.2.In terms of four types of solvent retention capacity,namely water solvent retention capacity(WSRC),lactic acid solvent retention capacity(LASRC),sucrose solvent retention capacity(Su SRC),and sodium carbonate solvent retention capacity(SCSRC),with the decrease of the HMW-GS numbers,both WSRC and LASRC showed a decreased tendency.The ranges for WSRC and LASRC were 61.26% to62.91% and 62.17% to 118.09% for A1-D1 lines,and 60.74% to 62.85% and 59.70% to115.43% for A2 to D2 line.In each sets of NILs,line D had the lowest Su SRC,and line B had the highest SCSRC.3.In terms of processing quality,grain protein content and softing value increased with the decrease of HMW-GS numbers.The ranges of grain protein content and softing value were 13.47 to 12.61% and 196.92 to 92.58 BU for A1-D1 lines,and 13.11 to12.44% and 184.25 to 92.25 BU for A2-D2 lines.However,Zeleny sedimentation value,gluten index,dough development time,dough stability time,farinograph quality number and water absorbance decreased with the decrease of HMW-GS numbers.The ranges for the above six quality parameters were 4.78 to 19.3 m L,0.03 to 0.93,0.95 to 1.25 min,0.47 to 1.93 min,12.50 to 20.50,and 48.32 to 50.81% for A1-D1 lines and 4.86 to 19.49 m L,0.03 to 0.96,0.86 to 1.52 min,0.56 to 2.49 min,14.83 to 24.50,and 48.08 to51.10%,for A2 to D2 lines.4.In terms of viscosity index,line A had the lowest peak viscosity and trough viscosity and the highest gelatinization temperature in each set of NILs.5.In terms of dough microstructure,the protein areas,percentage of protein areas(%),protein junction,junction density,total length of gluten,and branching rate of gluten decreased with the decrease of HMW-GS numbers,whereas the total number of endpoints and the percentage of endpoints showed the opposite trend.6.In terms of finished product quality,bread height,width,volume and specific volume,bread slice area,maximum slice height,perimeter,brightness,number of stomata,crispness and hardness of biscuits decreased with the decrease of HMW-GS numbers,whereas the stomatal diameter,wall thickness,and biscuit diameter showed the opposite trend.In summary,reducing the number of HMW-GS is beneficial to weak gluten and biscuit quality,which may be one of the breeding targets for weak gluten wheat and brewing wheat in the future.