Transcriptome Analysis Of Starch Synthesis Related Genes In Waxy And No-Waxy And DUS Test Of Foxtail Millets

Foxtail Millet is the main Miscellaneous grains crop in China,and it is also the dominant characteristic crop in the Inner Mongolia Autonomous Region.It has many advantages,such as comprehensive nutrition,the same medicine and food,and high-quality health care and so on.At present,the main cultivars on the market are mainly No-waxy,lack of Waxy cultivars.With the gradual improvement of living standards,consumers are increasingly demanding waxy cultivars that because of tasting better.Therefore,it is urgent to improve the eating quality of foxtail millet.In this study,Gonggu 68（Waxy）and Chigu 4（No-waxy）were used as materials to analyze the dynamic changes of grain-bound starch synthase（GBSSⅠ）activity during grain filling and the grains with the highest and lowest GBSSⅠactivity With reference to transcriptome sequencing,the gene expression related to starch synthesis in Gonggu 68（Waxy）and Chigu 4（No-waxy）at different filling stages was explored,and the differentially expressed genes in Waxy and No-waxy foxtail millet were discovered.Four foxtail millet cultivars and eight high-generation lines were used for DUS testing by SPSS 24.0 analysis software.The results were as follows:1.Gonggu 68 and Chigu 4 had the lowest GBSSⅠactivity on the first day of the filling stage,with 200 and 300 enzyme activity units,respectively;the highest on the fifth day of the filling stage,with 560 and 660 Enzyme activity unit.2.Compared with the first day of the filling period of Gonggu 68,the number of differential genes that were significantly up-regulated was 1332,and the number of differential genes that were significantly down-regulated was 1403.3.According to the results of GO and KEGG enrichment analysis in Gonggu 68,a total of 7 down-regulated genes related to amylopectin synthesis were screened in starch and sucrose metabolic pathways,namely LOC101754478,LOC101752753,LOC101786898,LOC101763655,LOC101776395,LOC101773221 and LOC101774505.4.Compared with the first day of filling period of Chigu 4,the number of differentially expressed genes that were significantly up-regulated was 3285,and the number of differentially expressed genes that were significantly down-regulated was5.According to the results of GO and KEGG enrichment analysis in Chigu 4,a total of 14 genes with larger differential expression folds were screened in starch and sucrose metabolic pathways.The differential expression fold of LOC101775037 was the highest 7.84 times.Except for LOC101765240,the other genes were all down-regulated.These genes encode endo-1,4-β-glucanase,β-glucosidase,α-amylase isoenzymes and other enzymes,which are closely related to plant starch synthesis.6.The DUS test showed that the agronomic traits of the 8 hybrid F_3:4 and F_4:5generation lines were at least one different from the female parent,and they were specific;N2014（02）-93-4-2 and 2014033-2Ⅰ-5B-4 accord with the DUS standard,that is,the above two strains have consistency,specificity and stability,and can be registered and regionally tested.