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Article|01 Jun 2020|OPEN
DNA methylome and transcriptome landscapes revealed differential characteristics of dioecious flowers in papaya
Ping Zhou1,2, Xiaodan Zhang3, Mahpara Fatima4, Xinyi Ma1, Hongkun Fang1, Hansong Yan1 & Ray Ming1,3,
1College of Life Sciences, FAFU and UIUC Joint Center for Genomics and Biotechnology, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Fujian Agriculture and Forestry University, 350002, Fuzhou, Fujian, China
2Fruit Research Institute, Fujian Academy of Agricultural Sciences, 350013, Fuzhou, Fujian, China
3Department of Plant Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
4College of Agriculture, Fujian Agriculture and Forestry University, 350002, Fuzhou, Fujian, China

Horticulture Research 7,
Article number: 81 (2020)
doi: 10.1038/hortres.2020.81
Views: 664

Received: 18 Sep 2019
Revised: 22 Mar 2020
Accepted: 23 Mar 2020
Published online: 01 Jun 2020

Abstract

Separate sexes in dioecious plants display different morphology and physiological characteristics. The differences between the two sexes lie in their highly differentiated floral characteristics and in sex-related phenotype, which is genetically determined and epigenetically modified. In dioecious papaya (Carica papaya L.), global comparisons of epigenetic DNA methylation and gene expressions were still limited. We conducted bisulfite sequencing of early-stage flowers grown in three seasons (spring, summer and winter) and compared their methylome and transcriptome profiles to investigate the differential characteristics of male and female in papaya. Methylation variances between female and male papaya were conserved among three different seasons. However, combined genome-scale transcriptomic evidence revealed that most methylation variances did not have influence on the expression profiles of neighboring genes, and the differentially expressed genes were most overrepresented in phytohormone signal transduction pathways. Further analyses showed diverse stress-responsive methylation alteration in male and female flowers. Male flower methylation was more responsive to stress whereas female flower methylation varied less under stress. Early flowering of male papaya in spring might be associated with the variation in the transcription of CpSVP and CpAP1 coinciding with their gene-specific hypomethylation. These findings provide insights into the sex-specific DNA methylation and gene expression landscapes of dioecious papaya and a foundation to investigate the correlation between differentiated floral characteristics and their candidate genes.