Multi-omics Analysis Revealed Molecular Regulation Network Of Heteromorphic Leaves Development Of P. Euphratica

Populus euphratica is mainly distributed on both banks of rivers that flow through desert areas.Due to long-term adaptation to the extremely dry continental climate,P.euphratica grows leaves of different shapes at different development stages and develops heteromorphic leaf characteristics.We obtained the following results through multi-sample collection and multi-omics analysis of P.euphratica heteromorphic leaves:(1)The expression level of narrow leaves is relatively narrow in cell division and cell cycle processes.At the same time,some key leaf shape-related transcription factors and genes such as GRF(Peu TF06G01147,Peu TF07G00075),STM(Peu TF07G00358,Peu TF05G02113,Peu TF06G02249)and ROT3(Peu TF13G01439,Peu TF14G00109,Peu TF13G00735)have also been found.Angustifolia has great similarities in the expression of transcriptomics.Compared with broadleaf,At the same time,some genes related to leaf shape function were also discovered,such as response to auxin-related gene Peu TF02G01021,LUG(Peu TF02G02270)that restricts cell expansion,and CAMTA transcription factor that participates in immune response.In the difference of tree ages,different leaf shapes will change with the changes of the age of the existing trees.At the same time,comparing the differences of leaf ages,it is found that the first leaf age is the key period for leaf development,leaf shape and leaf function Related genes will be highly expressed compared to the other two periods.(2)Changes in the content of endogenous hormones in P.euphratica leaves and the temporal and spatial laws of regulatory pathways: Growth hormone(IAA)and cytokinin in mature leaves of P.euphratica(ZR)and gibberellin positive regulation were enriched in the D-phase broadleaf(ovate leaf and broad-ovate leaf)modules,and genes related to the positive regulation of abscisic acid were enriched in the In the narrow leaf module of stage D(striped and lanceolate leaves);genes related to the positive cytokinin regulation pathway are enriched in the narrow leaf module of stage A and B,and the enriched genes are in the whole sample The expression level shows a relatively high expression in the broadleaf module.(3)Multi-omics control strategy for the development of heteromorphic leaves of P.euphratica: We found that the overall methylation level in the samples of the first period was generally low,and this phenomenon was particularly obvious in the broad-leaved samples.In the comparison of the degree of chromatin opening between lanceolate leaves and ovate leaves of D stage,the relative open areas of lanceolate leaves are mostly concentrated in the distant intergenic regions,and the DNA methylation level is relatively high,while the ovate leaves have relatively high levels of DNA methylation.At the same time,related genes PIN1(Peu TF12G00374),cytochrome P450(Peu TF05G00632),FLC(Peu TF10G01011)affecting leaf morphology and function were found.To systematically exploit the transcription landscape of P.euphratica leaves,here we combine four com-plementary high-throughput techniques: RNA-seq,ATAC-seq,DNA methylation and Hi-C to identify candidate genes and regulation mechanism related to leaf morphogenesis.First,we combined phenotypic physiology,transcriptomics and DNA methylation to identify the transcriptional dynamics and co-expression network of leaf types development in P.euphratica.ATAC-seq and Hi-C were used to further reveal the genes expression strategy associated with leaf morphogenesis.The results from this study provide a highly reliable panoramagram of the transcription output in P.euphratica,which builds a foundation for studying phenotypic and functional variations in leaf.