4.2.2 ⎪ Stronger enrichment in IT compared to SW under HLC
The well-characterized phenotypic features of cold acclimation do occur
in IT, but to a lesser extent than in SW. It is noteworthy that the
genes more strongly induced under HLC in IT compared to SW have been
implicated in abiotic stress responses, as was reported for chloroplast
glucose-6 phosphate/phosphate translocator GPT2 (Dyson et al.
2015), chloroplast envelope K+/H+antiporter KEA2 (Kunz et al. 2014), light-harvesting complexLHCB4.3 (Klimmek, Sjödin, Noutsos, Leister & Jansson 2006),
cytosolic phosphofructokinase (Kant et al. 2008), cytosolic
fumarase (Pracharoenwattana et al. 2010), ferritins (Petit, Briat
& Lobréaux 2001), and pyridoxal phosphate synthase (Denslow, Rueschhoff
& Daub 2007). Future research should further test the hypothesis that
both SW and IT make acclimatory adjustments that limit oxidative stress
under HLC conditions, but that changes in SW focus more on enhancement
of productivity (which also lowers excitation pressure more
effectively), while IT undergoes alternative evasive changes that are
somewhat less effective in controlling excitation pressure.
Moreover, genes exhibiting greater down-regulation in HLC in IT compared
to SW were those involved in growth hormone transport and signaling
(cytokinin-activated, auxin polar transport, and response to auxin). As
stated above, such effects could be related to the hormonal control of
vascular acclimation.