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Article|07 Mar 2022|OPEN
Methylation related genes affect sex differentiation in dioecious and gynodioecious papaya
Ping Zhou1 , Xiaodan Zhang2 , Xinyi Ma3 , Jingjing Yue3 , Zhenyang Liao3 and Ray Ming,2 ,
1Fruit Research Institute,Fujian Academy of Agricultural Sciences,Fuzhou 350013,Fujian, China
2Department of Plant Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
3FAFU and UIUC Joint Center for Genomics and Biotechnology, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Fujian Agriculture and Forestry University, Fuzhou 350002, Fujian, China
*Corresponding author. E-mail: rayming@illinois.edu

Horticulture Research 9,
Article number: uhab065 (2022)
doi: https://doi.org/10.1093/hr/uhab065
Views: 303

Received: 02 Jul 2021
Accepted: 25 Nov 2021
Published online: 07 Mar 2022

Abstract

Morphological, genic and epigenetic differences often exist in separate sexes of dioecious and trioecious plants. However, the connections and relationships among them in different breeding systems are still unclear. Papaya has three sex types, which is genetically determined and epigenetically regulated, and was chosen as a model to study sex differentiation. Bisulfite sequencing of genomic DNA extracted from early-stage flowers revealed sex-specific genomic methylation landscapes and seasonally methylome reprogramming processes in dioecious and gynodioecious papaya grown in spring and summer. Extensive methylation of sex-determining region (SDR) was the distinguishing epigenetic characteristics of nascent XY sex chromosomes in papaya. Seasonal methylome reprogramming of early-stage flowers in both dioecy and gynodioecy systems were detected, resulting from transcriptional expression pattern alterations of methylation-modification-related and chromatin-remodeling-related genes, particularly from those genes involved in active demethylation. Genes involved in phytohormone signal transduction pathway in male flowers have played an important role in the formation of male-specific characteristics. These findings enhanced the understanding of the genetic and epigenetic contributions to sex differentiation and the complexity of sex chromosome evolution in trioecious plants.