5.1 Transcription factors
Previous reviews had identified several transcription factor families as
hubs for plant responses to multiple stresses (Fujita et al., 2006;
Atkinson & Urwin, 2012; Rivero et al., 2022). MYC2 is a central player
in plant responses to biotic and abiotic stress (Anderson et al., 2004),
and plays a role in JA-induced defense genes and is a key regulator by
which ABA controls signaling related to biotic stress (Atkinson &
Urwin, 2012). MYB transcription factors are also a key group, as they
have been shown to be induced by drought, UV-B radiation, cold stress as
well as biotic stress (Atkinson & Urwin, 2012). Additionally, NAC and
AP2/ERF transcription factors have broad spectrum responses to biotic
and abiotic stress in multiple species (Atkinson & Urwin, 2012). More
targets for future research include WRKY, bZIP, TCP, and
calmodulin-binding transcription factor activator (CAMTA) transcription
factors (Atkinson & Urwin, 2012; Kissoudis et al., 2014 Rivero et al.,
2022). Several members of these transcription factor families (ERF, MYB,
bHLH, NAC, and WRKY) have been suggested to act as switches controlling
transcriptional reprogramming during plant development as well as in
tolerance to biotic and abiotic stresses. These transcription factors
are ideal candidates for engineering stress-tolerant plants (Erpen et
al. 2017, Baillo et al. 2019)
Furthermore, understanding post-translational regulation of
transcription factors is important, as this impacts expression of
downstream genes that can be key regulators of plant stress response.
These downstream genes include proline-rich proteins. For example, when
proline-rich proteins from pigeonpea (Cajanus cajan L.) were
constitutively expressed in Arabidopsis they provided enhanced tolerance
to multiple abiotic stresses such as osmotic, salt, and heat stress.
Meta-analyses of transcriptome datasets have revealed additional core
abiotic stress responsive genes (Dossa et al., 2019, Saidi et al.,
2022), include genes belonging to a member of the late embryogenesis
abundant family (LEA) (Huang et al. 2016, Chen et al. 2019), and alcohol
dehydrogenase (ADH) family members (Shi et al. 2017). Additionally, the
resistance gene, Xa7 , conferring bacterial blight resistance in
rice functions better at high temperatures, indicating elevated
temperature can have a positive impact on plant defense responses to
pathogens (Cohen et al., 2017). These genes could be key targets for
future research efforts.