Comparative analysis of polyamine metabolism in wheat and maize plants

Abstract

Please cite this article as: G. Szalai, K. Janda, E. Darkó, T. Janda, V. Peeva, M. Pál, Comparative analysis of polyamine metabolism in wheat and maize plants, Plant Physiology et Biochemistry (2017), doi: 10.1016/j.plaphy.2017.01.012. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. AbstractIn the present work changes in polyamine contents were investigated after various hydroponic polyamine treatments (putrescine, spermidine and spermine at 0.1, 0.3 and 0.5 mM concentrations) in two different crop species, wheat and maize. In contrast to putrescine, higher polyamines (spermidine and spermine) induced concentration-dependent oxidative damage in both crops, resulting in decreased biomass. The unfavourable effects of polyamines were more pronounced in the roots, and maize was more sensitive than wheat. The adverse effects of polyamine treatment were proportional to the accumulation of polyamine and the plant hormone salicylic acid in the leaves and roots of both plant species. Changes in polyamine content and catabolism during osmotic stress conditions were also studied after beneficial pre-treatment with putrescine. The greater positive effect of putrescine in wheat than in maize can be explained by differences in the polyamine metabolism under normal and osmotic stress conditions, and by relationship between polyamines and salicylic acid. The results demonstrated that changes in the polyamine pool are important for fine tuning of polyamine signalling, which influences the hormonal balance required if putrescine is to exert a protective effect under stress conditions.

The effects of putrescine are partly overlapping with osmotic stress processes in wheat

“…As it was previously reported under the same conditions osmotic stress increased the free SA content in the leaves . Also higher leaf SA content was detected, when PUT pre-treatment preceded PEG-induced osmotic stress compared to the control [11]. According to these our results also support the hypothesis that there is an antagonistic relationship between SA-dependent defence pathway and phytosulfokin signalling [37].…”

“…The experimental design was performed as in the previous experiment [11]. Briefly, after 7 days of growth in Hoagland solution, the seedlings were either grown further under control growth conditions in hydroponic solution or treated with 0.5 mM PUT hydroponically for 7 days.…”

“…In a recent review it was suggested that a group of genes that increase their translation in the presence of PAs, so called "PA modulon" [19] The beneficial effect of putrescine (PUT) pre-treatment, added to the hydroponic solution, against PEG-induced osmotic stress has been demonstrated earlier in wheat and maize plants [11]. The results demonstrated that fine tuning in the PA pool is important for PA signalling, which influences the hormonal balance required.…”

“…Involvement of PAs in plant responses to environmental stimuli has been demonstrated by several studies. The protective effects of elevated endogenous level (either due to exogenous PA treatment or to transgenic modification) have been reported in several plant species under various stress conditions [1][2][3][4][5][6][7][8][9][10][11]. Besides their direct protective role PAs regulate fundamental cellular processes as signalling molecules, suggesting that abiotic stress tolerance is mainly influenced via signalling processes rather than by their accumulation [12].…”

“…The results demonstrated that fine tuning in the PA pool is important for PA signalling, which influences the hormonal balance required. As more pronounced positive effects of PUT treatment were observed in wheat than in maize [11], in the present work only the wheat genotype was used as a continuation of the previous study in order to reveal a more detailed explanation for the background mechanism and processes behind the protective effect.…”