Transcriptome Analysis Of Maize Kernel Development

Maize(Zea mays L.)is the world's highest yield cereal crop.With the rapid increase in the number of people in the world,the food supply should also increase accordingly to meet the needs of human survival.To meet the increasing demand for human consumption,animal husbandry,and industrial uses(such as biofuels),continue to increase the production of corn and other grain crops(wheat,rice,barley,etc.),especially grain yield,and improve grain quality.It is necessary and urgent.It is of great theoretical and practical significance to deeply study the regularity of maize kernel development,improve maize grains yield and improve the quality of corn seeds.In this study,seeds or ovaries of high combining ability,high dehydration rate,and early maturing maize inbred line Yu816 were used as experiment materials to study the development of maize kernels,especially in the early stage of maize kernel development,from the morphological,histological and transcriptomics levels,and in combination with bioinformatics methods.The temporal patterns of gene expression in early maize kernel development has been studied in depth.The main findings are as follows:1.Based on the morphological and characteristic curve of grain growth and development,combined with detailed observation and analysis at the level of histology,the developmental period and characteristics of the Yu816 grain were accurately identified.Yu816 grain's growth and development were divided into five consecutive periods:the morphogenesis/blister stage(about 7?10 days after pollination),milk stage(about 14 days after pollination),dough stage(about 18?21 days after pollination),dent stage(about 24?39 days after pollination),and physiological maturity stage(about 42?45 days after pollination).At the stage of grain morphogenesis,structures such as endosperm and embryo are gradually formed.Cell proliferation and accumulation of storage compounds occurs mainly during the milk stage.2.At the early stage of kernel development,RNA-seq technology was used to perform transcriptome analysis on the seeds under pollination conditions[Y:6 DAS(0 DAP),10 DAS(4 DAP),14 DAS(8 DAP),18 DAS(12 DAP)and 21 DAS(15 DAP)]and the ovaries under pollination-prevention conditions[N:6 DAS,10 DAS,14 DAS,18 DAS and 21 DAS].The main results are as follows:(1)The gene expression patterns of starch and sucrose metabolism pathway genes and trehalose biosynthetic pathway genes were different,which resulted in the normal development of seeds under pollination conditions and the abnormal development of ovaries under non-pollination condition.(2)The key period for the accumulation of zein synthesis in Yu816 kernel is 21 days after silking(15 DAP).(3)MYB,ERF,NAC and other transcription factor families are mainly involved in the normal Yu816 seeds development under pollination conditions.Nevertheless,the transcription factor families such as WRKY,NAC,ERF are primarily involved in the abnormal development of Yu816 ovaries under non-pollination conditions.This study provided a preliminary atlas of spatiotemporal expression pattern of genes during the early development of maize kernels,and usefully explored the regulatory mechanism of maize kernel development,especially the early stage of maize kernel development.The results will provide support for in-depth study of maize seed yield and quality control mechanisms.