Molecular identification and functional characterization of a cyanogenic glucosyltransferase from flax (Linum unsitatissimum)

Abstract

Flax seed has become consumers' choice for not only polyunsaturated alpha-linolenic fatty acid but also nutraceuticals such as lignans and soluble fiber. There is, however, a major drawback of flax as a source of functional food since the seeds contain significant level of cyanogenic glucosides. The final step of cyanogenic glucoside biosynthesis is mediated by UDP-glucose dependent glucosyltransferase. To date, no flax cyanogenic glucosyl transferase genes have been reported with verified biochemical functionality. Here we present a study on the identification and enzymatic characterization of a first flax cyanogenic glucosyltransferase, LuCGT1. We show that LuCGT1 was highly active towards both aliphatic and aromatic substrates. The LuCGT1 gene is expressed in leaf tissues as well as in developing seeds, and its expression level was drastically reduced in flax mutant lines low in cyanogenic glucosides. Identification of LuCGT1 provides a molecular handle for developing gene specific markers for targeted breeding of low cyanogenic glucosides in flax.

In silico prediction of microRNA families involved in the biosynthesis of lignans and cyanogenic glycosides in flax (Linum usitatissimum L.)

“…Numerous studies reveal that lignans are particularly beneficial in the prevention and treatment of cancer, diabetes, and many other health issues associated also with female reproduction (Mueed et al 2023;Sirotkin 2023;Xi et al 2023). On the other hand, cyanogenic glycosides, as a fraction of antinutrients, may reduce these benefits and even act antagonistically to the synthesis of lignans (Kazachkov et al 2020;Zuk et al 2020). An important milestone will be achieving an optimal ratio of nutritional and antinutritional components while maintaining current physiological parameters (Harenčár et al 2021).…”

“…Its primary products are currently seeds that are rich in omega-3 fatty acids and fibre, with the amount of lignans being 800 times higher compared to other plants (Kajla et al 2015). Among its main antinutrients are cyanogenic glycosides, for which the breeding program is set up to minimize in contrast to lignan content (Fofana et al 2017b;Kazachkov et al 2020;Sharma et al 2021). For these purposes, microRNAs represent a valuable tool in agronomic trait analysis, and innovative in silico approaches are necessary for a successful breeding process (Chen et al 2021;Tan et al 2022).…”

“…The conversion involves (−)-pinoresinol-(−)-lariciresinol reductase 1, which processes it into (−)-lariciresinol and subsequently into (+)-secoisolariciresinol. This compound is then glycosylated to form (+)-secoisolariciresinol diglucoside by the Uridine glycosyltransferase UGT74S1 (Ghose et al 2014;Kazachkov et al 2020). Dirigent protein 1 operates with opposite stereospecificity and is responsible for the formation of (+)-pinoresinol from the same two coniferyl alcohol radical units (Markulin et al 2019).…”

“…Together with NADPH reductase, these enzymes can form a complex known as metabolon, which is attached to the membrane and operates very efficiently (Zhang and Fernie 2021;Del Giudice et al 2022). In the case of linustatin and neolinustatin, the diglucosidic bond is mediated by another nonspecific UDP-glucosyltransferase (Hartanti and Cahyani 2020;Kazachkov et al 2020;Yulvianti and Zidorn 2021). CG are stored in vacuoles, separated from their hydrolytic lyasesβ-glucosidases (De Brito and Martinoia 2018).…”

Prediction of MicroRNAs Involved in Lignan and Cyanogenic Glycosides Biosynthesis of Flax (Linum usitatissimum L.)

“…Its primary product are currently seeds that are rich in omega-3 fatty acids and bre and in which is the amount of lignans 800 times higher compared to another plants (Kajla et al, 2015). Among its main antinutrients belong cyanogenic glycosides for whose is the breeding program set up to minimizing by contrast to lignan´s content (Fofana et al, 2017b, Kazachkov et al, 2020. For these purposes the microRNAs represent a valuable tool in agronomic trait analysis and innovative in silico approaches are necessary in successful breeding process (Chen et al, 2021, Tan et al, 2022.…”