浙江红花油茶花叶型新品种'叠翠流金'叶色变异的细胞学、多组学分析

[Objective]'Diecui Liujin'is a new variety of Camellia chekiangoleosa cultivated by Jian gxi Academy of Forestry.This variety has both normal and mutant leaves,among which the mutant leav es emit yellowing mutations from the leaf veins,resulting in the formation of'flower leaves'.It is an id eal material for studying pigment synthesis and photosynthesis mechanisms.[Method]The formation mec hanism of Camellia chekiangoleosa leaf color varition clone'Diecui Liujin'and the effect of leaf color v ariation on photosynthesis were systematically expounded from the changes of cell structure,pigment con tent and transcription level.[Result]The results showed that the cell structure,pigment content and phot osynthesis of etiolated leaves had obvious changes,and the chloroplast thylakoid structure was not obvio us,showing a degradation phenomenon;The contents of chlorophyll a and Carotenoid were significantly lower than those of normal leaves,but the opposite was true for Chlorophyll b;Photosynthetic measurem ents showed that the photosynthetic efficiency of yellowed leaves was significantly lower than that of no rmal leaves.Using metabolome and Transcriptome sequencing techniques,we obtained 123.74 G of Clea n reads and 2756 kinds of metabolites from the transcriptome of 18 samples of Camellia chekiangoleosa.Through comparative analysis,we found 251 genes and 113 metabolites that showed significant differen ces in the two leaves at three stages.[Conclusion]Comprehensive analysis shows that the main reason f or the formation of yellowing leaves is the decrease of Teal chlorophyll a accompanied by the increase of yellow green Chlorophyll b,in which the genes that catalyze the degradation of chlorophyll a(PAO,RCCR)and transform to Chlorophyll b(CAO)play an important role.Meanwhile,the PsaB gene of PSI I for photosynthesis,the PsbB involved in electron transfer in PSI for photosynthesis,and the PetB subu nit of Cytochrome b complex all showed downregulation in the yellowing part,which may be the intern al reason for the decrease in photosynthesis in yellowed leaves.This study found that the main reason f or the formation of flowers and leaves was the decline of chlorophyll a accompanied by the rise of Chl orophyll b,and systematically clarified the molecular mechanism of the transformation of chlorophyll a t o Chlorophyll b,which led to the change of pigments and the decline of photosynthesis.This study will provide a basis for the study of leaf color variation and regulation.