5.3 MAPK cascades and heat shock factors (HSFs)
MAPK cascades are a key step in transduction of environmental cues to
internal signaling pathways (Rodriguez et al., 2010). MAPK signaling
cascades are involved in biotic stress and abiotic stress responses in a
range of plant species, including Arabidopsis, rice, tomato and cotton,
and link other pathways related to ROS and hormone signaling (Fujita et
al., 2006; Atkinson & Urwin, 2012; Kissoudis et al., 2014; Rivero et
al., 2022). This integration of signals from multiple stresses and plant
hormones indicates MAPK cascades are particularly important in
regulating biotic-abiotic stress crosstalk. Heat shock proteins (HSPs)
are molecular chaperones that protect and stabilize proteins during
stressful conditions (Bartels & Sunkar, 2005). HSPs are controlled by
HSFs, which are induced under biotic and abiotic stresses, including
heat, high light, and drought, across multiple species (Atkinson &
Urwin, 2012). HSFs also protect plants from oxidative stress and serve
as sensors for ROS to activate stress-responsive genes downstream
(Atkinson & Urwin, 2012). For example, recent work has shown increased
expression of specific HSF (HSFA1b ) in oilseed rape led to
increased resistance to stress and maintenance of yield (Mullineaux et
al., 2011). Taken together, both MAPKs and HSFs are key potential
regulators for conferring resiliency to biotic and abiotic stress
conditions under future climate change.