Abiotic stresses, such as drought, salinity,
extreme temperatures, chemical toxicity and oxidative
stress are serious threats to agriculture and the natural
status of the environment. Increased salinization of
arable land is expected to have devastating global effects,
resulting in 30% land loss within the next 25 years, and
up to 50% by the year 2050. Therefore, breeding for
drought and salinity stress tolerance in crop plants (for
food supply) and in forest trees (a central component of
the global ecosystem) should be given high research
priority in plant biotechnology programs. Molecular
control mechanisms for abiotic stress tolerance are
based on the activation and regulation of specific stressrelated
genes. These genes are involved in the whole
sequence of stress responses, such as signaling, transcriptional
control, protection of membranes and proteins,
and free-radical and toxic-compound scavenging.
Recently, research into the molecular mechanisms of
stress responses has started to bear fruit and, in parallel,
genetic modification of stress tolerance has also shown
promising results that may ultimately apply to agriculturally
and ecologically important plants. The present
review summarizes the recent advances in elucidating
stress-response mechanisms and their biotechnological
applications. Emphasis is placed on transgenic plants
that have been engineered based on different stressresponse
mechanisms. The review examines the following
aspects: regulatory controls, metabolite engineering,
ion transport, antioxidants and detoxification, late
embryogenesis abundant (LEA) and heat-shock proteins.