Epigenetic Factors Altered in Dehisced Anther Correlated to Seed Dormancy in &amp;lt;i&amp;gt;Paris polyphylla&amp;lt;/i&amp;gt; var. Yunnanensis

Xia Cheng,Feng Zhao,Zhen Zhao,Bin Wang,Xia Ling,Linyun Liu,Dingkang Wang

doi:10.4236/as.2019.1012112

Abstract

Paris polyphylla var. yunnanensis (Franch.), one of the best-known medicinal plants in China, has a dehiscent anther which physiologically work in pollination, however, the dehiscent anther always closes in response to darkness every day, and watering or raining every time. To explore this frequently closing and its unkown physiology, next-generation sequencing was performed, and the transcriptome was de novo assembled. RNA-sequencing was carried out in 15 samples including seven openning samples, four closed samples owing to darkness or watering, and tissue samples (leaf, petal, calyx, and stigma) were used for control. We obtained 72.75 GB data, assembled into 79,815 unigenes. Differentially expressed unigenes (DEGs) between opened and closed anther samples were 6231 and the DEGs between anther and control samples were 2831. Comparation between the two DEGs by KEGG enrichment showed that “plant hormone signal transduction” pathway is the most significant pathway for DEGs from closing anther vs. opening anther, and expression model of DEGs in the pathway might elicit change in germination and seed dormancy. Further examination of the action of the signal pathway on physiology showed “chromatin binding” function was prominent in “DNA binding” function of annotated DEGs between opened and closed anthers, of the 215 “chromatin binding” unigenes, 120 were involved in epigenetic silencing, and 50 of the epigenetic unigenes were directly related to germination or seed dormancy, strongly correlating anther closing to epigenetic modification and seed dormancy. These results were verified that at least three auxins involved in seed dormancy showed same expression patterns occurred in abnormal closing anther and seed embryo in Paris polyphylla var. yunnanensis. In conclusion, the information from transcriptome point out that frequent abnormal closing of dehiscent anthers possibly transfer the impact on seed dormancy, and epigenetic modification happened in closing may be the cause.

Highlights

Paris polyphylla is a temperate genus of flowering plants belonging to the family Trilliaceae that includes 24 species distributed throughout Europe and East Asia
Paris polyphylla var. yunnanensis (Franch.), one of the best-known medicinal plants in China, has a dehiscent anther which physiologically work in pollination, the dehiscent anther always closes in response to darkness every day, and watering or raining every time
Further examination of the action of the signal pathway on physiology showed “chromatin binding” function was prominent in “DNA binding” function of annotated Differentially expressed unigenes RNA-Seq (DEG) between opened and closed anthers, of the 215 “chromatin binding” unigenes, 120 were involved in epigenetic silencing, and 50 of the epigenetic unigenes were directly related to germination or seed dormancy, strongly correlating anther closing to epigenetic modification and seed dormancy

Summary

Introduction

Paris polyphylla is a temperate genus of flowering plants belonging to the family Trilliaceae that includes 24 species distributed throughout Europe and East Asia. Paris is native to Southwest China [1], and the Yunnan-Guizhou Plateau is considered the center of its diversity [2] [3]. As one of the most well-known medicinal plants in China, P. polyphylla var. From over-collection during the past decades, wild resources have become scarce, and P. polyphylla is considered an endangered species. The rate-limiting factors in the cultivation of P. polyphylla is prolonged dormancy (18 months) and slow growth from seed (3 - 4 years) [10] [11]. Understanding the mechanism of prolonged seed dormancy in this species is key to accelerating its propagation

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