Polyamine-Induced Hormonal Changes in eds5 and sid2 Mutant Arabidopsis Plants

Abstract

Polyamines are multifaceted compounds which play a role in regulating plant growth and stress tolerance in interactions with plant hormones. The aim of the present study was to reveal how exogenous polyamines influence the synthesis of salicylic acid, with a special emphasis on the effect of salicylic acid deficiency on the polyamine metabolism and polyamine-induced changes in other plant hormone contents. Our hypothesis was that the individual polyamines induced different changes in the polyamine and salicylic acid metabolism of the wild type and salicylic acid-deficient Arabidopsis mutants, which in turn influenced other hormones. To our knowledge, such a side-by-side comparison of the influence of eds5-1 and sid2-2 mutations on polyamines has not been reported yet. To achieve our goals, wild and mutant genotypes were tested after putrescine, spermidine or spermine treatments. Polyamine and plant hormone metabolism was investigated at metabolite and gene expression levels. Individual polyamines induced different changes in the Arabidopsis plants, and the responses were also genotype-dependent. Polyamines upregulated the polyamine synthesis and catabolism, and remarkable changes in hormone synthesis were found especially after spermidine or spermine treatments. The sid2-2 mutant showed pronounced differences compared to Col-0. Interactions between plant hormones may also be responsible for the observed differences.

Lipid kinases PIP5K7 and PIP5K9 are required for polyamine‐triggered K+ efflux in Arabidopsis roots

“…Importantly, Spm concentrations found to be effective in this work (low µ m range) are significantly lower than the basal polyamine levels in plant cells (Galston and Kaur‐Sawhney, 1995), and much lower than concentrations frequently used in other studies, where typically high µ m /low m m concentrations have been used (Sagor et al ., 2015; Marco et al ., 2019; Tajti et al ., 2019). In our hands, the effective concentration of Spm to induce PIP 2 revealed a clear saturation response at low µ m concentrations (Figure 1) and correlated with the dose‐dependent inhibition of root growth (Figure 6; Zarza et al ., 2019).…”

Salicylic Acid Signalling in Plants

“…These papers cover a wide range of aspects of SA-related mechanisms. They include a "classical" demonstration of the importance of SA in biotic stress [23] and the importance of the use of various mutants related to SA signalling [24,25], as well as focus on the crosstalk with other stress-related compounds [25,26]. There are also works investigating the effects of environmental factors on the SA-related signalling [26,27], and on the role of different SA analogue compounds [28].…”

“…However, their signalling role has only become apparent in recent years [29]. Tajti and co-workers recently demonstrated a possible crosstalk between the SA and polyamine signalling pathways [25]. They showed that the SA-deficient Arabidopsis mutant, sid2 plants, could be characterised with a different polyamine metabolism.…”

In silico Analysis of Polyamine Rich Transgenic Tomato Fruit Transcriptome for Salicylic Acid Biosynthesis

“…Bioinformatics studies revealing the correlation coefficient and clustering analyses might be of interest and provide a comprehensive understanding about the interaction between PAs and genes responsible for SA biosynthesis pathway. The effect of individual PAs on SA biosynthesis and on PA metabolism and vice versa has been previously studied in Arabidopsis plants by exogenous application of PAs or SA using SA mutants (Tajti et al, 2019). Synthesis of polyamine and its catabolism beside the pronounced changes in SA synthesis was upregulated by polyamines treatments in vitro, especially after SPD or SPM (Tajti et al, 2019).…”

“…The effect of individual PAs on SA biosynthesis and on PA metabolism and vice versa has been previously studied in Arabidopsis plants by exogenous application of PAs or SA using SA mutants (Tajti et al, 2019). Synthesis of polyamine and its catabolism beside the pronounced changes in SA synthesis was upregulated by polyamines treatments in vitro, especially after SPD or SPM (Tajti et al, 2019). Each PA was found to have a distinct role.…”