Article,
Ethylene triggers salt tolerance in maize genotypes by modulating polyamine catabolism enzymes associated with H2O2 production
ENVIRONMENTAL AND EXPERIMENTAL BOTANY, (2018)
DOI: 10.1016/j.envexpbot.2017.10.022
Abstract
The current study was undertaken to investigate if there is a
relationship between metabolisms of ethylene and polyamines in the
processes of salinity acclimation of salt-tolerant and salt-sensitive
maize genotypes. Biphasic ethylene production (at 5.5 and 12.5 h) was
registered only in salt-sensitive plants during NaCl exposure. In the
salt-tolerant genotype, the unique ethylene peak at 5.5 h was closely
related to increased polyamine accumulation (a polyamine-dependent H2O2
signalling process), whereas the same did not occur in the
salt-sensitive genotype. The absence of H2O2 signalling at 5.5 h in the
salt-sensitive genotype was related to a burst in ethylene production at
12.5 h, known as `stress ethylene', as well as a concomitant decrease in
total polyamine content by salinity. The lack of stress ethylene
synthesis in the salt-tolerant genotype was attributed to
down-regulation of 1-aminocyclopropane-1-carboxylic acid oxidase (ACO)
activity and ZmACO5b gene expression. Our findings suggest that ethylene
is intimately involved in salt stress acclimation through activation of
a complex pathway of signalling by H2O2 that is polyamine
catabolism-dependent.
