Proanthocyanidins in seed coat tegmen and endospermic cap inhibit seed germination in Sapium sebiferum

Faheem Afzal Shah; Jun Ni; Jing Chen; Qiaojian Wang; Wenbo Liu; Xue Chen; Caiguo Tang; Songling Fu; Lifang Wu

doi:10.7717/peerj.4690

Proanthocyanidins in seed coat tegmen and endospermic cap inhibit seed germination in Sapium sebiferum

PeerJ. 2018 Apr 26:6:e4690. doi: 10.7717/peerj.4690. eCollection 2018.

Authors

Faheem Afzal Shah^#¹, Jun Ni^#², Jing Chen², Qiaojian Wang¹, Wenbo Liu², Xue Chen², Caiguo Tang², Songling Fu¹, Lifang Wu²

Affiliations

¹ School of Forestry and Landscape Architecture, Anhui Agriculture University, Hefei, Anhui, China.
² Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, Anhui, China.

^# Contributed equally.

Abstract

Sapium sebiferum, an ornamental and bio-energetic plant, is propagated by seed. Its seed coat contains germination inhibitors and takes a long time to stratify for germination. In this study, we discovered that the S. sebiferum seed coat (especially the tegmen) and endospermic cap (ESC) contained high levels of proanthocyanidins (PAs). Seed coat and ESC removal induced seed germination, whereas exogenous application with seed coat extract (SCE) or PAs significantly inhibited this process, suggesting that PAs in the seed coat played a major role in regulating seed germination in S. sebiferum. We further investigated how SCE affected the expression of the seed-germination-related genes. The results showed that treatment with SCE upregulated the transcription level of the dormancy-related gene, gibberellins (GAs) suppressing genes, abscisic acid (ABA) biosynthesis and signalling genes. SCE decreased the transcript levels of ABA catabolic genes, GAs biosynthesis genes, reactive oxygen species genes and nitrates-signalling genes. Exogenous application of nordihydroguaiaretic acid, gibberellic acid, hydrogen peroxide and potassium nitrate recovered seed germination in seed-coat-extract supplemented medium. In this study, we highlighted the role of PAs, and their interactions with the other germination regulators, in the regulation of seed dormancy in S. sebiferum.

Keywords: ABA; Endospermic cap; GA; Proanthocyanidins; Sapium sebiferum; Seed dormancy; Tegmen.

Grants and funding

This work was funded by Anhui Natural Science Foundation (1708085QC70), the National Natural Science Foundation of China (11375232&31500531), the Science and Technology Service program of Chinese Academy of Sciences (KFJ-STS-ZDTP-002&KFJ-SW-STS-143-4), the Grant of the President Foundation of Hefei Institutes of Physical Science of Chinese Academy of Sciences (YZJJ201502&YZJJ201619), the major special project of Anhui Province (16030701103), and the research and technology project of Anhui province (1501031079). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.