Phytotoxic cyanamide affects maize (Zea mays) root growth and root tip function: from structure to gene expression.
Cyanamide (CA) is a phytotoxic compound produced by four Fabaceae species: hairy vetch, bird vetch, purple vetch and black locust. Its toxicity is due to complex activity that involves the modification of both cellular structures and physiological processes. To date, CA has been investigated mainly in dicot plants. The goal of this study was to investigate the effects of CA in the restriction of the root growth of maize (Zea mays), representing the monocot species. CA (3mM) reduced the number of border cells in the root tips of maize seedlings and degraded their protoplasts. However, CA did not induce any significant changes in the organelle structure of other root cells, apart from increased vacuolization. CA toxicity was also demonstrated by its effect on cell cycle activity, endoreduplication intensity, and modifications of cyclins CycA2, CycD2, and histone HisH3 gene expression. In contrast, the arrangement of microtubules was not altered by CA. Treatment of maize seedlings with CA did not completely arrest mitotic activity, although the frequency of dividing cells was reduced. Furthermore, prolonged CA treatment increased the proportion of endopolyploid cells in the root tip. Cytological malformations were accompanied by an induction of oxidative stress in root cells, which manifested as enhanced accumulation of H2O2. Exposure of maize seedlings to CA resulted in an increased concentration of auxin and stimulated ethylene emission. Taken together, these findings suggested that the inhibition of root growth by CA may be a consequence of stress-induced morphogenic responses.
Plant Breeding and Acclimatization Institute, Młochów Research Center, Platanowa 19, 05-831 Młochów, Poland. Electronic address: d.soltys@ihar.edu.pl.
Dorota
D
Soltys
Department of Botany, Warsaw University of Life Sciences - SGGW, Nowoursynowska 159, 02-776 Warsaw, Poland.
Anna
A
Rudzińska-Langwald
Department of Botany, Warsaw University of Life Sciences - SGGW, Nowoursynowska 159, 02-776 Warsaw, Poland.
Wojciech
W
Kurek
Plant Breeding and Acclimatization Institute, Młochów Research Center, Platanowa 19, 05-831 Młochów, Poland.
Katarzyna
K
Szajko
Department of Plant Genetics, Physiology and Biotechnology, University of Technology and Life Sciences in Bydgoszcz, Kaliskiego 7, 85-789 Bydgoszcz, Poland.
Elwira
E
Sliwinska
Department of Plant Physiology, Warsaw University of Life Sciences - SGGW, Nowoursynowska 159, 02-776 Warsaw, Poland.
Renata
R
Bogatek
Department of Plant Physiology, Warsaw University of Life Sciences - SGGW, Nowoursynowska 159, 02-776 Warsaw, Poland.
Agnieszka
A
Gniazdowska
D003484:Cyanamide / Q000494:pharmacology*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects*; D046529:Microscopy, Electron, Transmission; D018384:Oxidative Stress / Q000187:drug effects; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development / Q000648:ultrastructure; D020133:Reverse Transcriptase Polymerase Chain Reaction; D036226:Seedlings / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000648:ultrastructure; D003313:Zea mays / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development / Q000648:ultrastructure
D010940:Plant Proteins; D003484:Cyanamide
Allelopathy; Border cells; Cell cycle; Cyanamide; Endoreduplication