NtMYB12 Positively Regulates Flavonol Biosynthesis and Enhances Tolerance to Low Pi Stress in Nicotiana tabacum

Abstract

Phosphorus (P) is an essential macronutrient for plant growth and development. The concentration of flavonol, a natural plant antioxidant, is closely related to phosphorus nutritional status. However, the regulatory networks of flavonol biosynthesis under low Pi stress are still unclear. In this study, we identified a PFG-type MYB gene, NtMYB12, whose expression was significantly up-regulated under low Pi conditions. Overexpression of NtMYB12 dramatically increased flavonol concentration and the expression of certain flavonol biosynthetic genes (NtCHS, NtCHI, and NtFLS) in transgenic tobacco. Moreover, overexpression of NtMYB12 also increased the total P concentration and enhanced tobacco tolerance of low Pi stress by increasing the expression of Pht1-family genes (NtPT1 and NtPT2). We further demonstrated that NtCHS-overexpressing plants and NtPT2-overexpressing plants also had increased flavonol and P accumulation and higher tolerance to low Pi stress, showing a similar phenotype to NtMYB12-overexpressing transgenic tobacco under low Pi stress. These results suggested that tobacco NtMYB12 acts as a phosphorus starvation response enhancement factor and regulates NtCHS and NtPT2 expression, which results in increased flavonol and P accumulation and enhances tolerance to low Pi stress.

Genome-Wide Analysis of Long Non-Coding RNAs (lncRNAs) in Two Contrasting Soybean Genotypes Subjected to Phosphate Starvation

“…6), which was supported by previous studies focusing LP in soybean [32,42]. Previous research showed that NtMYB12 acts as a phosphorus starvation response enhancement factor and regulates NtCHS and NtPT2 expression, which results in increased avonol and P accumulation and enhances tolerance to LP stress [43]. In this study, targets of lncRNAs were enriched as KEGG pathway including avonoid, iso avonoid and phenylpropanoid biosynthesis, indicating that those lncRNAs may be involved in secondary metabolites to regulate P responsive genes, which needs further research.…”

Genome-wide analysis of long non-coding RNAs (lncRNAs) in two contrasting soybean genotypes subjected to phosphate starvation

“…6), and these ndings are supported by previous studies focusing on LP in soybean [33,43]. Previous research has shown that NtMYB12 acts as a phosphorus starvation response enhancement factor and regulates NtCHS and NtPT2 expression, which results in increased avonol and P accumulation and enhances tolerance to LP stress [44]. In this study, targets of lncRNAs were enriched in various KEGG pathways, including avonoid, iso avonoid and phenylpropanoid biosynthesis, which indicates that these lncRNAs might be involved in the synthesis of secondary metabolites to regulate P-responsive genes, but this hypothesis needs further research.…”

Enhanced reproductive thermotolerance is associated with increased accumulation of flavonols in pollen of the tomatohigh-pigment2 mutant

“…Importantly, the beneficial effect of hp2 in stress tolerance may extend beyond heat stress due to the fact that flavonols play an important role in protecting against oxidative stress which accompanies many other environmental stresses such as cold, drought and nutrient starvation (Nakabayashi et al 2014;Song et al 2020;M. Zhao et al 2019;Zandalinas et al 2017).…”