Low Temperature-Enhanced Flavonol Synthesis Requires Light-Associated Regulatory Components in Arabidopsis thaliana

Abstract

Plants are continuously exposed to a myriad of stresses, which lead to the formation of secondary metabolites including flavonoids. Studies suggest that low temperature exposure leads to enhanced flavonoid accumulation in Arabidopsis thaliana. In addition, flavonoid biosynthesis is regulated by light through various regulatory factors. Therefore, plants may possess the capability to integrate light and low temperature signals for survival under freezing conditions. However, the detailed molecular mechanism and the regulatory factors associated with light- and low temperature- responsive flavonoid biosynthesis remain largely unknown. Here, we report a strict requirement for light for the low temperature-enhanced flavonol biosynthesis. Low temperature-induced expression of biosynthetic genes as well as flavonol accumulation was hampered in ELONGATED HYPOCOTYL (hy5) and myb11myb111myb12 triple mutants as compared with the wild type in Arabidopsis. Overexpression of AtHY5 in the hy5 mutant restored induction of gene expression and flavonol accumulation in response to low temperature in light. Metabolite and gene expression analysis also suggests a negative role for CONSTITUTIVE PHOTOMORPHOGENIC1 (COP1) in accumulation of flavonols in response to low temperature. Overexpression of AtMYB12 enhanced accumulation of flavonols under low temperature in a light-dependent manner. Together, our analysis suggests the requirement for HY5 and flavonol-specific MYB regulatory factors for low temperature-induced flavonol synthesis.

Seasonal Patterns in Spectral Irradiance and Leaf UV-A Absorbance Under Forest Canopies

“…However, we did not find that I flav increased with low summer air temperatures ( Figure S12) and likewise the minimum air temperature on measurement days had poor explanatory value in our data both for seasonal changes in adaxial and abaxial I flav ( Supplementary A2). Low temperature-enhanced flavonol synthesis is dependent on light (Bhatia et al, 2018), and although this could have relevance especially in high latitudes with extended daylight hours during summer, it seems unlikely to be the only mechanism producing the differences in I flav between adaxial and abaxial leaf sides that we found ( Figure S6). A combination of harsh environmental conditions, including excessive irradiance and low temperatures during early spring, could feasibly explain the trends in I flav , as reported for partially exposed plants compared to those under snowpack in winter (Solanki et al, 2019).…”

Genome-wide characterization and expression analyses of the MYB superfamily genes during developmental stages in Chinese jujube

“…9). According to previous studies, the MYB TF of Arabidopsis is involved in many secondary metabolic processes, such as the flavonoid metabolic pathway, glucosinolate biosynthesis, and anthocyanin biosynthesis (Stracke et al, 2007; Bhatia et al, 2018; Wei et al, 2015). For example, the MdMYBPA1 TF of red-fleshed apple responded to low temperatures by redirecting the flavonoid biosynthetic pathway from proanthocyanidin to anthocyanin production (Liu et al, 2015).…”

“…During continuous light treatments, the levels of McMYB10 increased and promoted the expression levels of McCOP1-1 and McCOP1-2 as well as anthocyanin biosynthesis in crabapple (Li et al, 2018). MYB TFs are also involved in flavonoid/phenylpropanoid metabolism; for example, overexpression of the AtMYB12 gene of Arabidopsis enhanced the accumulation of flavonoid content under low temperatures in a light-dependent manner (Bhatia et al, 2018). During strawberry ripening, the MYB10 gene in Fragaria × ananassa plays a general regulatory role in the flavonoid/phenylpropanoid pathway (Puche et al, 2014).…”

“…During strawberry ripening, the MYB10 gene in Fragaria × ananassa plays a general regulatory role in the flavonoid/phenylpropanoid pathway (Puche et al, 2014). In addition, ATMYB12 (Bhatia et al, 2018), ATMYB018 (Ballesteros et al, 2001), ATMYB21 (Shin et al, 2002), ATMYB075 , and ATMYB090 (Li et al, 2006) genes are involved in the light signaling pathway in Arabidopsis . R2R3-MYB TF family members in petunia ( Petunia hybrida ) are developmentally and environmentally regulated to control complex floral and vegetative pigmentation patterning (Albert et al, 2011).…”

iTRAQ-based comparative proteomic analysis in mature leaves of Ethiopian mustard (Brassica carinata) provides insights into the whole-proteomic profiles and the role of anthocyanin biosynthesis in leaf color diversity

“…TAC synthesis can also be regulated by fertilizers [63], such as nitrogen [64,65] and phosphate [66]. Light [67][68][69][70], short-day signals [71] and low temperature [72] can also affect the TAC biosynthesis pathway. Therefore, all of the pathways involved in the synthesis, degradation and absorption of these factors can regulate TAC biosynthesis in this study.…”