Morphological observation and protein expression of fertile and abortive ovules in Castanea mollissima

Bingshuai Du; Qing Zhang; Qingqin Cao; Yu Xing; Ling Qin; Kefeng Fang

doi:10.7717/peerj.11756

Morphological observation and protein expression of fertile and abortive ovules in Castanea mollissima

PeerJ. 2021 Jul 21:9:e11756. doi: 10.7717/peerj.11756. eCollection 2021.

Authors

Bingshuai Du^{1

2}, Qing Zhang³, Qingqin Cao^{1

3}, Yu Xing^{1

3}, Ling Qin^{1

3}, Kefeng Fang^{1

2

4}

Affiliations

¹ Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing University of Agriculture, Beijing, China.
² College of Landscape Architecture, Beijing University of Agriculture, Beijing, China.
³ Key Laboratory for Agricultural Application and New Technique, College of Plant Science and Technology, Beijing University of Agriculture, Beijing, China.
⁴ Key Laboratory of Urban Agriculture (North China, Ministry of Agriculture P. R. China), Beijing University of Agriculture, Beijing, China.

Abstract

Chinese chestnuts (Castanea mollissima Blume.) contain 12-18 ovules in one ovary, but only one ovule develops into a seed, indicating a high ovule abortion rate. In this study, the Chinese chestnut 'Huaihuang' was used to explore the possible mechanisms of ovule abortion with respect to morphology and proteomics. The morphology and microstructure of abortive ovules were found to be considerably different from those of fertile ovules at 20 days after anthesis (20 DAA). The fertile ovules had completely formed tissues, such as the embryo sac, embryo and endosperm. By contrast, in the abortive ovules, there were no embryo sacs, and wide spaces between the integuments were observed, with few nucelli. Fluorescence labelling of the nuclei and transmission electron microscopy (TEM) observations showed that cells of abortive ovules were abnormally shaped and had thickened cell walls, folded cell membranes, condensed cytoplasm, ruptured nuclear membranes, degraded nucleoli and reduced mitochondria. The iTRAQ (isobaric tag for relative and absolute quantitation) results showed that in the abortive ovules, low levels of soluble protein with small molecular weights were found, and most of differently expressed proteins (DEPs) were related to protein synthesis, accumulation of active oxygen free radical, energy synthesis and so on. These DEPs might be associated with abnormal ovules formation.

Keywords: Abortive ovules; Castanea mollissima Blume; Fertile ovules; iTRAQ.

Grants and funding

This work was supported by the National Key Research & Development Program of China (No. 2018YFD1000605) and the National Natural Science Foundation of China (No. 31270719). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.