Male Sterility in Maize after Transient Heat Stress during the Tetrad Stage of Pollen Development

Author(s)
Kevin Begcy, Tetyana Nosenko, Liang-Zi Zhou, Lena Fragner, Wolfram Weckwerth, Thomas Dresselhaus
Abstract

Shifts in the duration and intensity of ambient temperature impair plant development and reproduction, particularly male gametogenesis. Stress exposure causes meiotic defects or premature spore abortion in male reproductive organs, leading to male sterility. However, little is known about the mechanisms underlying stress and male sterility. To elucidate these mechanisms, we imposed a moderate transient heat stress on maize (Zea mays) plants at the tetrad stage of pollen development. After completion of pollen development at optimal conditions, stress responses were assessed in mature pollen. Transient heat stress resulted in reduced starch content, decreased enzymatic activity, and reduced pollen germination, resulting in sterility. A transcriptomic comparison pointed toward misregulation of starch, lipid, and energy biosynthesis-related genes. Metabolomic studies showed an increase of Suc and its monosaccharide components, as well as a reduction in pyruvate. Lipidomic analysis showed increased levels of unsaturated fatty acids and decreased levels of saturated fatty acids. In contrast, the majority of genes involved in developmental processes such as those required for auxin and unfolded protein responses, signaling, and cell wall biosynthesis remained unaltered. It is noteworthy that changes in the regulation of transcriptional and metabolic pathway genes, as well as heat stress proteins, remained altered even though pollen could recover during further development at optimal conditions. In conclusion, our findings demonstrate that a short moderate heat stress during the highly susceptible tetrad stage strongly affects basic metabolic pathways and thus generates germination-defective pollen, ultimately leading to severe yield losses in maize.

Organisation(s)
Functional and Evolutionary Ecology, Department of Ecogenomics and Systems Biology, Large-Instrument Facility for Mass Spectrometry in Life Sciences
External organisation(s)
Universität Regensburg (UR), University of Florida, Gainesville, Helmholtz-Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt
Journal
Plant Physiology
Volume
181
Pages
683-700
No. of pages
18
ISSN
0032-0889
DOI
https://doi.org/10.1104/pp.19.00707
Publication date
10-2019
Peer reviewed
Yes
Austrian Fields of Science 2012
Plant physiology, Metabolomics , Plant ecology, Biochemistry
Keywords
ASJC Scopus subject areas
Portal url
https://ucris.univie.ac.at/portal/en/publications/male-sterility-in-maize-after-transient-heat-stress-during-the-tetrad-stage-of-pollen-development(d6864a01-3dd1-4b1d-8374-3b4e78dd198e).html