The Analysis Of Protein Content Accumulation Dynamics And Expression Difference Of Related Genes In Seed Development In Brassica Napus L.

Rape is not only an important oil crop in the world,but also an important source of vegetable protein.There are some studies have shown that rapeseed protein can obtain a large number of active peptides through proper enzymatic hydrolysis or certain chemical modifications.And these active peptides have good bioactivity and physicochemical property.At present,most researches on rape are related to the increase of oil content,and the reports on rapeseed protein of Brassica napus L and the dynamic change or the relative expression of related genes of protein content during the seed development are few and far between.And it is also existing that the study of the seed development period is shorter or the study materials selected are less,which is not typical to illuminate the dynamic change or the relative expression of related genes during the seed development.This experiment was based on the high and low protein strains of B.napus L from different genetic backgrounds and had carried out two years exclusive criteria repetitive experimental study.And we made use of Coomassie brilliant blue method to determine the protein content of 4~9 periods of seed development in each strain to analyze the dynamic change of protein content and intervariation.And then we made use of Real-time quantification PCR to contrast expression pattern and expression difference of two key genes of protein synthesis,Cruciferin and Napin,and two transcription factors LEC1 and LEC2 during seed development of B.napus L to understand the natural law of protein content dynamic change,which providing relevant theoretical basis to promote germplasm resources innovation and new varieties breeding,at the same time,promoting the exploitation of rapeseed protein or relative products of rapeseed peptides.The main results of this study are as follows:1.The protein content dynamic change and the difference between high and low protein strains of brassica napus showed that:(1)The protein content dynamic change of high and low protein strains during the seed development was similar to the "~" type.The protein content dynamic change of developmental seeds in the two-year repeat test was similar,but the seed development of materials 2016~2017 were later than that of materials 2015~2016 and the dynamic delay time of protein accumulation in different strains was different.Two peaks appeared in protein accumulation during seed development.The first peak was around 25 days after flowering and the second peak was around 35~40 days after flowering.There would be a slight increase in protein content during maturation and the protein content of high-protein strains would change faster than that of low-protein strains.(2)The variance analysis of protein content during the development of high and low protein strains showed that the protein content between materials or in sampling period or of the interaction between sampling period and materials were all significantly different,which signified that the performance of seed protein content was closely related to the genetic background of the material and the seed development period.The multiple comparison analysis of the protein content in the developmental seeds of high and low protein strain showed that the protein content of high and low protein strains during maturation(60 days after flowering)was significantly different,which meaned that the protein content was inconsistent in the high and low protein strains and the difference was obvious and the protein content reached the highest level in the seed development study period.2.The analysis of expression level of genes involved in protein synthesis in high and low protein strains showed that:(1)The relative expression model of two key genes Cruciferin and Napin and two transcription factors LEC1 and LEC2 were overall similar and the relative expression level during early seed development was low and increased followed by a decrease in trend entirely for the first time.When the relative expression level of two key genes Cruciferin and Napin reached the peak,the protein content would decrease to a minimum.It showed that Cruciferin and Napin might play a role in inhibiting protein synthesis.When the relative expression level of two transcription factors LEC1 and LEC2 reached the peak,the protein content would increase to a maximum,and the relative expression level continued to rise,meanwhile,the protein content reached the maximum during maturation.It showed that LEC1 and LEC2 might promote protein synthesis.(2)From the level of expression,we can see that the level of expression of Cruciferin was higher than that of Napin and LEC1 and LEC2.And the level of expression of LEC1 and LEC2 especially the relative expression peak level in the high protein strains was higher than that in the low protein strains entirely.3.The correlation analysis between protein content and expression level of the related genes showed that:(1)The correlation analysis of expression level of Cruciferin and Napin in the high and low protein strains of two years performed identicaly.The correlation analysis of expression level of Cruciferin and LEC1 in the high and low protein strains of materials 2015~2016 performed identicaly.The correlation analysis of protein content and expression level of Cruciferin or expression level of Cruciferin and LEC2 or Napin and LEC1 in the high and low protein strains of materials 2015~2016 all performed inconsistently.And the correlation analysis of expression level of LEC1 and LEC2 in the high and low protein strains of materials 2016~2017 also performed inconsistently.(2)The total relationship of protein synthesis related genes in high and low protein strains was different and there were multiple relationship of action.And the relationship with protein content was more complicated.