Effect of Salt Stress on the Regulation of Maize (Zea mays L.) Genes Involved in Polyamine Biosynthesis

Abstract

A cDNA for spermidine synthase (SPDS), which converts putrescine to the higher polyamine spermidine using decarboxylated S-adenosylmethionine as a cofactor, was isolated from Zea mays leaves (Zmspds2A). Comparison of the deduced amino acid sequence revealed a high homology (81.9%) with Oryza sativa SPDS2. RT-PCR analyses showed that Zmspds2A was equally expressed in leaves, stem and roots. In contrast, transcripts of other genes related to polyamine biosynthesis (Zmodc, adc and samdc) showed tissue-specific regulation. The effect of salt stress on the expression of all these genes in maize leaves exposed to NaCl solutions of different concentrations was analysed. Our results showed that only Zmodc and Zmspds2A were up-regulated by salt stress; whereas the other two genes were barely affected by this treatment. In addition to Zmspds2A, a second transcript encoding a maize spermidine synthase (Zmspds2B) that also became up-regulated by salt stress, was identified. Comparison of partial cDNA sequences of transcripts Zmspds2A and Zmspds2B with the corresponding genomic DNA region revealed the existence of alternative splicing mechanism, opening a new aspect in plant polyamine biosynthesis modulation under abiotic stress.

Salt stress in maize: effects, resistance mechanisms, and management. A review

“…Rodríguez-Kessler et al (2006) reported the upregulation of two genes, Zmodc and Zmspds2A, responsible for polyamine and spermidine synthesis under salt stress in maize. Genotypic differences in the relative concentration of six β-expansin transcripts together with differences in the abundance of β-expansin protein were observed in response to NaCl stress.…”

Polyamines and their ability to provide environmental stress tolerance to plants

“…This indicated that the genes were disparately regulated during stress, a phenomenon which could be dependent upon several factors, such as plant species, duration, and intensity of stress and stress sensitivity of the experimental materials (Chattopadhyay et al 1997;Li and Chen 2000a;Hao et al 2005a, b;Liu et al 2006b). In spite of the existence of several polyamine biosynthetic enzymes, the global expressions of a whole set of the genes in response to stress has only been analyzed in a few cases (Urano et al 2003;Rodríguez-Kessler et al 2006;Alcázar et al 2006a;Liu et al unpublished data). It remains unclear why the genes in the polyamine biosynthetic gene family responded differently in response to stress.…”

Chilling tolerance in Nicotiana tabacum induced by seed priming with putrescine

“…Because of their fully protonated and polycationic nature at physiological pH, PAs can bind strongly to negatively charged cellular components such as nucleic acids, proteins and phospholipids . PAs are biologically active compounds involved in various physiological processes, and numerous studies reported that PAs can improve plant resistance to various abiotic stresses (Alcazar et al 2010;Rodríguez-Kessler et al 2006). Several mechanisms for the protective nature of PAs have been postulated, including stabilizing the function of chromosomes (Kasinathan and Wingler 2004), retarding lipid peroxidation and preserving membrane integrity (Ha et al 1998).…”