Comparative transcriptome analysis of two reproductive modes in Adiantum reniforme var. sinense targeted to explore possible mechanism of apogamy

Qi Fu,Long-Qing Chen

doi:10.1186/s12863-019-0762-8

Abstract

BackgroundApogamy is a unique asexual reproduction in the ferns, in which somatic cells of gametophytes go through dedifferentiation and then differentiate into haploid sporophytes bypassing fertilization. Restricted to the lack of genomic information, molecular mechanisms of apogamy have remained unclear. Comparative transcriptome analysis was conducted at six stages between sexual reproduction and apogamy in the fern Adiantum reniforme var. sinense, in an effort to identify genes and pathways that might initiate the asexual reproduction.ResultsApproximately 928 million high-quality clean reads were assembled into 264,791 unigenes with an average length of 615 bp. A total of 147,865 (55.84%) unigenes were successfully annotated. Differential genes expression analysis indicated that transcriptional regulation was more active in the early stage of apogamy compared to sexual reproduction. Further comparative analysis of the enriched pathways between the early stages of the two reproductive modes demonstrated that starch and sucrose metabolism pathway responsible for cell wall was only significantly enriched in asexual embryonic cell initiation. Furthermore, regulation of plant hormone related genes was more vigorous in apogamy initiation.ConclusionThese findings would be useful for revealing the initiation of apogamy and further understanding of the mechanisms related to asexual reproduction.

Highlights

Apogamy is a unique asexual reproduction in the ferns, in which somatic cells of gametophytes go through dedifferentiation and differentiate into haploid sporophytes bypassing fertilization
In this study, it was concluded that different transcriptome regulating networks were developed between the sexual reproduction and apogamy in the fern
The starch and sucrose metabolism relating to cell wall might play a key role in affecting apogamy initiation

Summary

Introduction

Apogamy is a unique asexual reproduction in the ferns, in which somatic cells of gametophytes go through dedifferentiation and differentiate into haploid sporophytes bypassing fertilization. Restricted to the lack of genomic information, molecular mechanisms of apogamy have remained unclear. As popular ornamental foliage plants, the ferns are cultivated in many countries and have gradually gained more and more attention and increasing demand all over the world [1]. The species such as Adiantum and Drynaria are considered as medicinal plants in curing the human disease in multiple fields. Ferns are unique among land plants in having separate and autotrophic gametophytes and sporophytes. There are several studies focusing on the genes promoting the apogamy in Physcomitrella patens [12] and Ceratopteris richardii [13, Fu and Chen BMC Genetics (2019) 20:55

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