Chemistry Reference
In-Depth Information
by multiple stress factors acting simultaneously. Thus for plants exposed in diverse stress
conditions, struggling for surviving, they organically adapt a complicated interplay of
signaling cascade to percepting stress signal, then amplifying, transmitting, and finally
triggering stress responses. Furthermore, there do exist overlap between different kinds of
stress responses, which truly explains the cross-tolerance phenomenon, a measure taken by
plants facing with combining stresses. Here, we are going to introduce signal transduction
mechanisms in plants under stressful circumstances, hoping to give readers a general idea
about how plants survive in different stressful situations.
2. Signal transduction
In general, for plant cells, signal transduction starts from the receptor activation, then the
generation of second messengers translating the primary external signal to intracellular
signals. These intracellular messengers will be further interpreted by their co-workers
resulting in the inspiration of downstream pathways. During the whole process, reversible
protein phosphorylation frequently happens; this can activate various transcription factors
inducing the expression of stress responsive genes. Moreover, other components are also
essential for the pathway to process. They have always been mentioned as signaling
partners, mainly working in recruiting and assembling signal complexes, targeting signaling
molecules, as well as controlling their lifespan.
Simply saying, the signal transduction pathway is a delicate cooperating process conducted
by each single participator including receptors/sensors, second messengers, phosphoprotein
cascades, transcription factors, and stress-responsive genes. Eventually the precise and
optimal response will be triggered to protect plants from damages in a large sense. As far as
we know, signal transduction is indispensable for many cellular activities and their
coordination, and most of its steps are complicated occurring in a time and space-dependent
manner. In the following part, we are going to explore every single step of signal
transduction in order to understand how plants cope with various stress in their lifespan.
2.1. Sensors
2.1.1. Complexity in researching on sensors
Sensors act as the molecules pioneering in perceiving stress stimulus and relaying the signal
to downstream molecules to initiate the signal transduction pathway. As the first
participator in the pathway, they must be of great researching meaning. However, they are
also the mainly intricate role for us to recognize.
Firstly, most of the abiotic stress signals themselves are complicated which probably
comprise several physical or chemical signals. Taken the cold stress as an example, it can
induce both osmotic stress and mechanistic stress. Similarly, drought may be accompanied
by osmotic stress, ionic stress, a mechanistic signal, and heat stress in some cases. Based on
these facts, it is natural for us to deduce that for plants there probably exists inequality in
