J Integr Plant Biol. ›› 2019, Vol. 61 ›› Issue (5): 598-610.DOI: 10.1111/jipb.12766

Special Issue: Seed development

• Research Articles • Previous Articles     Next Articles

A VPE-like protease NtTPE8 exclusively expresses in the integumentary tapetum and is involved in seed development

Wei Wang, Hanxian Xiong, Rongxin Lin, Nantian Zhao, Peng Zhao* and Meng-Xiang Sun*   

  1. State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China.

    Email: Mengxiang Sun (mxsun@whu.edu.cn, Dr. Sun is fully responsible for the distribution of all materials associated with this article); Peng Zhao (pzhao2000@whu.edu.cn)
  • Received:2018-08-27 Accepted:2018-12-17 Online:2018-12-27 Published:2019-05-01

Abstract: Programmed cell death (PCD) is an essential process for development, and shows conserved cytological features in both plants and animals. Caspases are well-known critical components of the PCD machinery in animals. However, currently few typical counterparts have been identified in plants and only several caspase-like proteases are known to be involved in plant PCD, indicating the existence of great challenge for confirming new caspase-like proteases and elucidating the mechanisms regulating plant PCD. Here, we report a novel cysteine protease, NtTPE8, which was extracted from tobacco seeds and confirmed as a new caspase-like protease. Recombinant NtTPE8 exhibited legumain and caspase-like proteolytic activities, both of which could be inhibited by the pan-caspase inhibitor (Z-VAD-FMK). Notably, NtTPE8 possessed several caspase activities and the capacity to cleave the cathepsin H substrate FVR, indicating a unique character of NtTPE8. NtTPE8 was exclusively expressed in the integumentary tapetum and thus, is the first specific molecular marker reported to date for this cell type. Down-regulation of NtTPE8 caused seed abortion, via disturbing early embryogenesis, indicating its critical role in embryogenesis and seed development. In conclusion, we identified a novel caspase-like cysteine protease, NtTPE8, exclusively expressed in the integumentary tapetum that is involved in seed development.

Editorial Office, Journal of Integrative Plant Biology, Institute of Botany, CAS
No. 20 Nanxincun, Xiangshan, Beijing 100093, China
Tel: +86 10 6283 6133 Fax: +86 10 8259 2636 E-mail: jipb@ibcas.ac.cn
Copyright © 2022 by the Institute of Botany, the Chinese Academy of Sciences
Online ISSN: 1744-7909 Print ISSN: 1672-9072 CN: 11-5067/Q