Transition from somatic embryo to friable embryogenic callus in XXXX : dynamic changes in cellular structure, physiological status, and gene expression profiles.

@entity2085 @entity7243 @entity3264 @entity948 @entity5906 @entity969 @entity3929 @entity413
UNASSIGNED: Friable embryogenic callus (FEC) is considered as the most suitable material for efficient genetic transformation of @entity7243 . Heavy genotype dependence of FEC induction and amenability to somaclonal variation limits the production and maintenance of reliable FEC. Identifying key elements involved in biological processes from @entity2085 ( @entity2085 ) to FEC at different stages provides critical insights for FEC improvement. Cytological observation showed a dramatic change of subcellular structures among @entity2085 , fresh FEC (FFEC), and old FEC (OFEC). Decrease of @entity969 and increase of @entity948 and @entity413 were detected in OFEC. A total of 6871 differentially expressed genes (DEGs) were identified from @entity2085 , FFEC, and OFEC by RNA-seq. Analysis of the DEGs showed that FEC induction was accompanied by the process of dedifferentiation, whereas the epigenetics modification occurred during the continuous subculturing process. The cell structure was reconstructed, mainly including the GO terms of "cell periphery" and "external encapsulating structure"; in parallel, the internal mechanisms changed correspondingly, including the biological process of glycolysis and metabolisms of @entity3929 , @entity5906 , and @entity3264 . The significant reduction of genomic DNA methylation in OFEC indicated altered gene expression via chromatin modification. These results indicate that the induction and long-term subculture of FEC is a complicated biological process involving changes of genome modification, gene expression, and subcellular reconstruction. The findings will be useful for improving FEC induction and maintenance from farmer-preferred @entity7243 cultivars recalcitrant to genetic transformation, hence improving @entity7243 through genetic engineering.
