SlMYB12 Regulates Flavonol Synthesis in Three Different Cherry Tomato Varieties

Abstract

Cherry tomato (Lycopersicon esculentum M.) is considered a healthy fruit worldwide due to its wide range of nutrients. Flavonol, one of the major nutrients in cherry tomato, has antioxidant and cell-modulating properties. In this study, we showed a correlation between the expression of SlMYB12 and flavonol content (R2 = 0.922). To characterize the function of SlMYB12, SlMYB12-overexpressing transgenic tomato plants were generated in three different cherry tomato varieties. Significant increases in flavonol content and flavonol biosynthetic gene expression were identified in SlMYB12-overexpressing plants. Therefore, we suggest that SlMYB12 plays a positive role in the flavonol biosynthesis pathway in cherry tomatoes, which further indicates a potential role as a marker in analyzing flavonol content in different cherry tomato varieties.

Different Fruit-Specific Promoters Drive AtMYB12 Expression to Improve Phenylpropanoid Accumulation in Tomato

“…The gradient as follow: t = 0.0 min, 20% B; t = 10 min, 30% B; t = 25 min, 90% B; t = 27 min, 90% B; t =28 min, 20% B; t = 32 min, 20% B, each sample was injected 10 µL and the flow rate was 1 mL/min. Detection by ultraviolet (UV) chromatograms was recorded at 325 nm and the column temperature was 35 °C [ 30 ]. All phenylpropanoid standards, rutin, naringenin chalcone and kaempferol rutinoside were obtained from Sigma-Aldrich.…”

“…MdMYB3 in apples can induce flavonols synthesis [ 28 ]. Specific expression of AtMYB12 in tomato fruits increased flavonols and hydroxycinnamates content to as much as 10% of fruit dry weight [ 29 , 30 ]. Moreover, the AtMYB12 acts as an activating factor for phenylpropanoid synthesis [ 31 ].…”

“…Although these promoters have been used to modify tomatoes genetically, the regulatory efficiency differences and the regulatory model of the phenylpropanoid synthesis pathway are still unclear. E4 and E8 exhibited a higher expression level in fruits than in the leaves, and their expression levels increased significantly as the fruit ripening proceeded [ 30 , 43 , 44 , 45 ]. PG initiator was cloned from the multi-polymer semi-lactate PG gene, found only in ripe tomato fruits [ 46 ].…”

“…Since phenylpropanoid biosynthesis is dominated by a series of genes, the use of transcription factors activates or suppresses metabolism-related genes, providing effective ways to engineer plants enriched with valuable secondary metabolites [ 2 ]. Although studies revealed that, as an MYB transcription factor, AtMYB12 allows positive regulation of flavonoid biosynthesis, the stability and effectiveness of the AtMYB12 expression in fruit varies widely among proponents [ 30 , 51 ]. In the current study, AtMYB12 was driven by four fruit-specific promoters, downstream regulatory gene expression, and phenylpropanoid accumulation.…”

Genetic Gains With Selection for Yield and Soluble Solids Content in Cherry Tomato Hybrids

“…Cherry tomato (Lycopersicon esculentum Mill.) is fruit rich in various organic and inorganic compounds (Wang et al, 2018), and its popularity has grown due to increased consumption of minimally processed foods. It presents a composition different from other types of tomato, generally with higher levels of dry matter, soluble solids, titratable acidity, flavor index, b-carotene, ascorbic acid, total phenolics, and antioxidant activity (Figas et al, 2015).…”