Physiological And Transcriptome Sequencing Analysis Of Leaf Color Of Acer Pseudosieboldianum In Autumn

Acer pseudosieboldianum is a deciduous tree of Acer in Aceraceae,and its leaves are beautiful in shape and red in color.It is a colorful leaf tree with high ornamental value in northeast China.At present,there are few researches in Acer pseudosieboldianum,especially on the color mechanism.Thus,in this study,we used the leaves of Acer pseudosieboldianum to research the dynamic changes in pigment content and main inclusions,in order to explore the color mechanism of Acer pseudosieboldianum leaves from a physiological and biochemical perspective.A new generation of high-throughput sequencing was used to sequence the transcriptome of Acer pseudosieboldianum leaves at different color changing stages without reference genome,enriched its transcriptome data information,and provided background reference for subsequent research.The distribution and expression of different genes were analyzed in the process of leaf color,and finally finded the color mechanism of Acer pseudosieboldianum from the molecular level,so as to provide the basis for its landscape application and further research on the change of leaf color of other Acer species,and lay the foundation for leaf color gene regulation and directional molecular breeding,and cultivate new varieties of color leaves.The comprehensive analysis was made of the test results and gotten the following conclusions:1.The pigment content and physiological indexes of Acer pseudosieboldianum leaves were analyzed in different color changing periods in autumn,the conclusions showed that the chlorophyll content decreased and the anthocyanin content increased in the process of changing from green to red,which indicated that anthocyanin was the main factor affecting the red color of Acer pseudosieboldianum leaves.There was no significant correlation between anthocyanin synthesis and sucrose,starch content.And there was a extremely significant negative correlation between anthocyanins,nitrogen and potassium.2.Five anthocyanins were detected in the leaves of Acer pseudosieboldianum.There were Peonidin O-hexoside,Rosinidin O-hexoside,Cyanidin 3-O-glucoside(Kuromanin),Cyanidin 3,5-O-diglucoside(Cyanin)and Pelargonidin 3-O-beta-D-glucoside(Callistephin chloride).It is worth mentioning that Peonidin O-hexoside,Cyanidin 3-O-glucoside(Kuromanin)and Cyanidin 3,5-O-diglucoside(Cyanin)have significant differences in their content change in two of the tested periods,meaning these may be the key substances determining the final color of Acer pseudosieboldianum.3.A total of 67.47 Gb of clean data was obtained from these sequencing results.After assembly,50,501 unigenes were identified,and after the function annotation of unigenes,35316 unigenes annotation results were obtained.A total of 16521 differentially expressed genes were screened from Acer pseudosieboldianum leaves at different color changing stages;The different expression genes GO function were annotated to 42 functional subgroups,among which metabolic process in biological process,membrane in cell components and catalytic activity in molecular function were highly enriched.The enrichment analysis of different expression genes KEGG pathway mainly regulated the biological processes of flavonoids biosynthesis and ribosome.4.In the flavonoid/anthocyanin biosynthesis pathway,20 structure genes were identified,encoding almost all known enzymes involved in flavonoid/biosynthesis,and screened out the related genes involved in leaf color formation of Acer pseudosieboldianum,including anthocyanin synthetase(ANS),dihydroflavonol reductase(DFR),flavanone 3-hydroxylase(F3H),and flavonoid 3-glucosyltransferase(UFGT),etc.Also,we screened out the regulatory genes,such as MYB,bHLH and WD40,etc.