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Front. Plant Sci. | doi: 10.3389/fpls.2018.00595

Oxidative stress and aberrant programmed cell death are associated with pollen abortion in isonuclear alloplasmic male-sterile wheat

 Zihan Liu1, Xiaoyi Shi1, Sha Li1,  Lingli Zhang1 and  Xiyue Song1*
  • 1College of Agronomy, Northwest A&F University, China

Cytoplasmic male sterility is crucial for the utilization of hybrid heterosis and it possibly occurs in parallel with tapetal programmed cell death (PCD) and oxidative metabolism responses. However, little is known about the mechanisms that underlie pollen abortion in wheat. Therefore, we obtained two isonuclear alloplasmic male sterile lines (IAMSLs) with Aegilops kotschyi and Ae. juvenalis cytoplasm. Compared with the maintainer line, cytochemical analyses of the anthers demonstrated that the IAMSLs exhibited anomalous tapetal PCD and organelles, with premature PCD in K87B1-706A and delayed PCD in Ju87B1-706A. We also found that the dynamic trends in reactive oxygen species (ROS) were consistent in these two IAMSLs during anther development and they were potentially associated with the initiation of tapetal PCD. In addition, the activities of ROS-scavenging enzymes increased rapidly, whereas nonenzymatic antioxidants were downregulated together with excess ROS production in IAMSLs. Real-time PCR analysis showed that the expression levels of superoxide dismutase, catalase, and ascorbate peroxidase genes, which encode important antioxidant enzymes, were significantly upregulated during early pollen development. Thus, we inferred that excessive ROS and the abnormal transcript levels of antioxidant enzyme genes disrupted the balance of the antioxidant system and the presence of excess ROS may have been related to aberrant tapetal PCD progression, thereby affecting the development of microspores and ultimately causing male sterility. These relationships between the mechanism of PCD and ROS metabolism provide new insights into the mechanisms responsible for abortive pollen in wheat.

Keywords: cytoplasmic male sterility, Gene Expression, ROS metabolism, tapetal programmed cell death, wheat (Triticum aestivum L.)

Received: 10 Nov 2017; Accepted: 16 Apr 2018.

Edited by:

Michael J. Considine, University of Western Australia, Australia

Reviewed by:

Serena Varotto, Università degli Studi di Padova, Italy
Pedro Diaz-Vivancos, Facultad de Biología, Universidad de Murcia, Spain  

Copyright: © 2018 Liu, Shi, Li, Zhang and Song. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Prof. Xiyue Song, Northwest A&F University, College of Agronomy, Xianyang, China, songxiyue@126.com