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Morphogenesis and global analysis of transcriptional profiles of Celastrus orbiculatus aril: unravelling potential genes related to aril development

Zu, Kuiling, Li, Jianxia, Dong, Shubin, Zhao, Yunyu, Xu, Shenjian, Zhang, Zhixiang, Zhao, Liangcheng
Genes & genomics 2017 v.39 no.6 pp. 623-635
Celastrus orbiculatus, aril, cDNA libraries, complementary DNA, databases, genomics, indole acetic acid, integument, morphogenesis, ornamental value, quantitative polymerase chain reaction, sequence analysis, signal transduction, transcription (genetics), transcription factors, transcriptome, unigenes
As a specialized seed appendage, the aril is a noteworthy and taxonomically important feature of Celastrus orbiculatus; the aril also has important ornamental value and biological functions. To better understand the mechanism of aril development, paraffin sections were used to examine its morphogenesis, and RNA-sequencing (RNA-seq) technology was employed for transcriptional profiling of the developing aril. Our results revealed that the aril of C. orbiculatus was formed by the cells of the exostomal region of the outer integument. By analyzing global changes in the transcriptome, 41,560,806, 42,789,340, and 44,496,748 clean reads from three cDNA libraries were generated and assembled into 87,600 unigenes with N50 of 1328 bp, in which 31,971 (36.49%) were annotated to Nr database. Furthermore, a total of 25,914 (29.79%), 14,394 (16.4%) and 11,957 (13.65%) genes were successfully annotated with hierarchical 48 GO terms, 26 KOGs and 32 KEGG pathways. Totally, 104, 1887 and 1967 differently expressed genes were identified in CO-F2 versus CO-F3, CO-F2 versus CO-YF1 and CO-F3 versus CO-YF1, respectively. GO and KEGG pathway analyses of DEGs involved in cell–cell communication and plant hormone signal transduction contributed to aril development were identified. Furthermore, we found putative key target genes of WRKY, Aux/IAA, ARF and MADS-box family’s transcription factors related to aril development. Real-time qPCR was performed on eight genes randomly selected from important transcription factors to validate the expression profiles obtained by RNA-seq. This work provides a platform for future genetic and functional genomics research on the molecular mechanisms of aril structure, and expands our understanding of the molecular mechanism and evolutionary analysis of aril development in other members of the Celastraceae.