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.