The Grain Quality Difference And Nitrogen Fertilizer Regulation Of Different HMW-GS Deletions In Ningmai 9

In recent years,the consumption of biscuits and cakes has been increasing,so it is of great significance to produce weak gluten wheat that meets the requirements for biscuit production.Biscuit powder requires low protein content and weak gluten strength.HMW-GS is an important component of glutenin macropolymer(GMP).It is the structural unit of gluten network,which determines the elasticity and viscosity of wheat dough.Its deletion will directly weaken the dough strength.In this study,we used different HMW-GS single deletions in Ningmai 9 as materials to study the changes of wheat grain quality and response to nitrogen fertilizer in wheat after three sub-bases of Glu-1 loci,and combined with wheat grain stratification technology,the cryosection and laser microdissection capture technique to explore the effect of HMW-GS deletion on the flour quality of wheat grain.The results provided an effective technical approach for the cultivation of weak gluten wheat.1.The accumulation,transportation and nitrogen metabolism difference and nitrogen fertilizer regulation of different HMW-GS deletions in Ningmai 9.The accumulation of dry matter in different HMW-GS deletions was different.At the flowering and maturity stages,the 8 subunits deletions had higher dry matter accumulation.The 2 subunit deletions had medium dry matter accumulation during flowering,but the storage capacity of pre-flowering storage was larger.The stems,leaves and glumes at the maturity stage were lower and the grain weight was higher.The deletion of HMW-GS has a greater effect on the nitrogen content of the stalk at the flowering stage,and has less effect on the leaves and hulls,and also has a certain effect on the nitrogen content of the grain at the maturity stage.In the mature stage,the 8 subunits deletion showed lower nitrogen content in stems and leaves,and higher nitrogen content in grains,,but 2 subunits deletion was opposite,which higher nitrogen content in the vegetative organs and lower nitrogen content in the grains.The total nitrogen accumulation of plants in the 2,7,and 12 subunit deletions under NO treatment was lower than that of wild type and not sensitive to nitrogen fertilizer.The nitrogen accumulation of leaves,hulls and grains of the 1 subunit deletion was lower,and the total nitrogen accumulation was lower,which was less affected by nitrogen fertilizer.The nitrogen accumulation of leaves,hulls and grains of 8 subunits deletions was always high and sensitive to nitrogen fertilizer,the nitrogen accumulation of stems was higher than other deletions.The difference in pre-flowering nitrogen assimilation of different deletion was large.The pre-flowering nitrogen assimilation of the 2 subunit deletions was significantly lower than that of the wild type,and the 8 subunit deletions had higher nitrogen assimilation than wild type.The 1 subunit deletion has lower nitrogen balance index,NR activity and GS activity,and is less affected by nitrogen fertilizer.The NR and GS activities of the 2 subunit deletions increased significantly from the flowering stage to the 10th day,the 8 and 12 subunit deletions increased from the flowering stage to the 20th day.2.The protein quality difference and nitrogen fertilizer regulation of different HMW-GS deletions in Ningmai 9.The yield of each deletion was reduced compared to the wild type.After the deletion of Glu-B1 and Glu-A1 loci,the yield decreased more than that of Glu-D1 locus.After applying nitrogen fertilizer,the yield increase of each deletion was lower than that of wild type(except for the 12 subunit deletion under N120 treatment),while the yield increase of the 7-subunit and 2-subunit deletions was higher than that of the other deletions.The protein content of the flour in the 8 subunits deletion was higher than that in the wild type,while the protein content of the other deletions was not significantly different from that of the wild type.The protein contents and HMW-GS content of the 7,2 and 1 subunit deletions were lower than those of the wild type,and the GMP content of the 2 subunits deletion was lower than that of the wild type.Each of the deletions showed similar behavior under NO treatment after nitrogen application.The protein content of the 1 subunit deletion was slow to respond to nitrogen fertilizer,and the protein content remained at a low level after nitrogen application.After deletion of 1 subunit or 2 subunits,the grain protein content was not significantly different from wild type,but HMW-GS/LMW-GS,GMP content,wet gluten content decreased,while 8 subunits deletion showed reversed results.The results of HMW-GS gene expression showed that the relative expression content of 1Bx7 gene of 8 subunit deletion was lower than that of wild type,while the relative expression content of 1Ax1 gene increased,and the expression content of 1 subunit exceeded wild type.The relative expression contents of the 1By8 gene and the 1Dx2 gene of the 7-subunit deletion were decreased,and the contents of the 8 subunit and the 2 subunit were lower than those of the wild type.The relative expression content of the 1By8 gene of the 12 subunit deletion was increased,and the content of the 8 subunit was higher than that of the wild type.It can be seen that the protein and gluten contents of the 2 and 1 subunit deletion are low,and the response to nitrogen fertilizer is slow.Although the yield of the 2 subunit deletion is lower than that of the wild type,the yield is higher compared to other deletion,thus the 2 subunit deletion is suitable for producing weak gluten wheat.3.The flour quality difference and nitrogen fertilizer regulation of different grain layers in different HMW-GS deletions in Ningmai 9.The total protein content,GMP content,high and low molecular weight glutenin subunits of each deletions showed a trend of increasing and then decreased in the grain from the outside to the inside.The protein content,GMP,and HMW-GS content of the 1,2 subunit deletions were significantly lower than those of the wild type.Deionized water solvent retention,sodium carbonate solvent retention,and sucrose solvent retention were lower than wild type,while lactic acid retention increased.The content of proline and glutamic acid increased,and the content of isoleucine decreased.The ratio of protein body area of the 2 subunit and 1 subunit deletion of the grain at different levels of the grain was significantly lower in the cells of the back,side and abdomen than in the wild type,and was less affected by the nitrogen fertilizer.The expression of HMW-GS related genes is different in different levels.The 1Ax1 gene was up-regulated in the endosperm of the 8 subunit deletion,but after application of the nitrogen fertilizer,the 1Ax1 gene was down-regulated compared to the wild type.The 1Dx2 gene and the 1By7 gene were down-regulated,and were down-regulated compared with the wild-type after nitrogen application.The deletion of the 1 subunit was up-regulated in the 1Dx2 gene in the endosperm,and 1Bx7 was up-regulated in the endosperm and endosperm after nitrogen application,and the 1Dy8 gene in the endosperm was down-regulated.The 1Ax1 gene and the 1By7 gene of the 2 subunit deletion were down-regulated in three parts compared with the wild type.The 1Dy8 gene was slightly up-regulated in the outer endosperm.The 1Ax1 gene was significantly up-regulated in the outer and middle endosperm compared with the wild type after nitrogen application.The 1By7 gene is not significantly different from the wild type,and the 1Dy8 gene is slightly upregulated in the outer endosperm.In summary,after the delete of 2,1 subunits,the quality of protein and other products are in line with the requirements of weak gluten wheat,and the response to nitrogen fertilizer is slow.The difference between the protein of the 2 subunit and the 1 subunit deletion,the content of HMW-GS,GMP and the wild type was mainly in the aleurone layer to the endosperm,but the difference in the endosperm in the peel and P7 layer was not obvious.The content of the 1 and 8 subunits of the 2 subunit deletion was lower than that of the wild type,and the relative expression of the 1By8 and 1Ax1 genes was down-regulated,mainly in the middle and endosperm.In addition,after the application of nitrogen fertilizer,the yield of the 2 subunit deletion is still lower than that of the wild type,but the growth rate is at a higher level.Therefore,the quality index of the 1 and 2 subunit deletions is in line with the requirement of weak gluten wheat,and the yield of the 2 subunit deletion can be maintained stable.