Agriculture Reference
In-Depth Information
Chapter 5
Polyamines Contribution to the Improvement
of Crop Plants Tolerance to Abiotic Stress
Ana Bernardina Menéndez, Andrés Alberto Rodriguez,
Santiago Javier Maiale, Kessler Margarita Rodriguez,
Bremont Juan Francisco Jimenez and Oscar Adolfo Ruiz
1 Introduction
Polyamines (PAs) are aliphatic biogenic amines present in most Prokaryotes and all
Eukaryotic organisms (Takahashi and Kakehi
2010
; Fuell et al.
2010
). These small
molecules are essential for life. At physiological pH, PAs are found as protonated,
positively charged molecules containing two (diamine), three (triamine) or four
(tetraamine) amine groups, what favors their electrostatic interaction with several
macromolecules such as nucleic acids, proteins and lipids (Igarashi and Kashiwagi
2000
; Childs et al.
2003
). The polycationic nature of PAs is one of the most impor-
tant properties linking these natural compounds to several cellular and physiologi-
cal processes, and new connections between PAs and other molecules, revealing
new insights into the PA biological role are being continually discovered.
At the cellular level, PAs participate in diverse fundamental processes such as
transcription, translation, DNA replication, chromatin condensation, cell signal-
ing, cell division and differentiation, senescence and cell death. In addition, di-
verse roles in membrane stabilization, ion channel regulation, cation-anion balance,
modulation of enzyme activities, and protein modification have also been described
(Childs et al.
2003
; Shabala et al.
2007
; Handa and Mattoo
2010
).
In plants, PAs are present from micromolar (∼10 μM) to millimolar concentra-
tions (Galston and Sawhney
1990
). The most common PAs are spermidine (Spd;
NH
2
(CH
2
)
3
NH(CH
2
)
4
NH
2
), spermine (Spm; NH
2
(CH
2
)
3
NH(CH
2
)
4
NH(CH
2
)
3
NH
2
)
and their obligate precursor putrescine (Put; NH
2
(CH
2
)
4
NH
2
). Spd is structurally an
unsymmetrical molecule that can be aminopropylated at each end, forming either
