Effects Of O2 On Grain Quality And Ear Row Number In Maize

Vitamins are small molecular compounds that are indispensable to the human body and must be obtained through diet.Carotenoids are not only the main source of vitamin An in the body,but also have the effects of anti-oxidation,immune regulation,anti-cancer and anti-aging,which play an important role in human health.Vitamin A deficiency can lead to the risk of blindness and susceptibility to diseases in children.Vitamin A deficiency is a global health problem,especially in some economically backward regions.In addition,with the continuous improvement quality of life,people pay more attention to healthy diet.Among the three major crops maize,rice and wheat,only maize contains vitamin A protocarotene.Maize is a staple grain widely planted in the world.Increasing the content of vitamin A protocarotenoid in maize grain through breeding and cultivation is the most economical,safe and reliable method to solve vitamin A deficiency and ensure nutritional security.Therefore,elucidating the mechanism of carotenoid accumulation in corn grains and cultivating new corn varieties rich in carotenoids are of great significance for food security and nutritional security.In this study,a mutant related to carotenoid content was found from maize EMS mutant database.Candidate gene Opaque2(O2)was identified by Ec Mut Map method.In order to decipher biological functions of O2 in regulating carotenoid biosynthesis in maize kernel.We measured the protein content,amino acid composition,crude fat content,starch content and carotenoid content in O2 mutant and wild type,and analyzed O2 in regulating the expression of carotenoid synthesis genes.In order to explore the potential value of O2 in breeding,we also analyzed whether there were differences in agronomic traits between the mutant and the wild type.The related results are as follows:1)There were no differences in protein content and crude fat content between o2mutant and wild type B73.The contents of lysine,aspartic acid and arginine ino2 mutant increased significantly,while the content of proline decreasedsignificantly,but there was no significant difference in the other 14 amino acids.Total starch content and amylose content in o2 mutant decreased significantly.2)Compared with wild type B73,the content of carotenoids such as zeaxanthin,β-carotene,zeaxanthin,lutein,β-crypxanthin,anther xanthin and α-carotene in o2 mutants decreased significantly.3)LUC report system analysis showed that O2 could regulate the expression of PSY1,ZDS and Lcy E genes.4)Compared with wild type B73,the o2 mutant became thicker in ear and cob,the number of rows per ear increased by 16.73%,and there was no significant difference in grain width and grain length.This study shows that O2 can regulate not only the accumulation of carotenoids,starch,aspartic acid and arginine in maize grains,but also the number of rows per ear,which has the potential to increase yield.It provides a theoretical basis and material basis to improve the nutritional value of maize grain and increase the yield by regulating the expression of O2 gene.We also preliminarily studied the molecular mechanism of O2 regulating carotenoid synthesis,and further research is needed to explore the specific regulation mechanism.