Limin Han

The lipoxygenase (LOX) pathway plays a crucial role in the biosynthesis of characteristic aroma compounds in fruit. Despite the progress in understanding the LOX pathway in model plants like tomato, the distinct roles of individual members within the LOX gene family in flavor formation in the complex octoploid strawberry are still not fully understood. In this study, we identified 13 LOX genes in the strawberry genome and focused on a specific lipoxygenase gene, designated FaLOX11, which exhibited the highest expression during fruit ripening. Spatiotemporal expression analysis revealed that FaLOX11 expression was significantly correlated with 3-hexenal accumulation, quantified via headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry (HS-SPME-GC-MS). Functional characterization via transient overexpression of FaLOX11 in strawberry fruits resulted in a significant increase in C6 volatile content, specifically a ~72% increase in 3-hexenal content. Conversely, RNA interference (RNAi)-mediated transient silencing of FaLOX11 significantly downregulated the expression of this gene and led to a marked reduction in the production of these key aroma compounds. Our findings demonstrate that FaLOX11 acts as a positive regulator of C6 aldehyde and alcohol biosynthesis, thereby playing a pivotal role in determining the characteristic aroma profile of strawberry fruit. This study provides new insights into the LOX pathway in strawberry and lays a solid molecular foundation for improving strawberry flavor quality.

The MYB transcription factor gene family is among the most extensive superfamilies of transcription factors in plants and is involved in various essential functions, such as plant growth, defense, and pigment formation. Salvia nemorosa is a perennial herb belonging to the Lamiaceae family, and S. nemorosa has various colors and high ornamental value. However, there is little known about its genome-wide MYB gene family and response to flower color formation. In this study, 142 SnMYB genes (MYB genes of S. nemorosa) were totally identified, and phylogenetic relationships, conserved motifs, gene structures, and expression profiles during flower development stages were analyzed. A phylogenetic analysis indicated that MYB proteins in S. nemorosa could be categorized into 24 subgroups, as supported by the conserved motif compositions and gene structures. Furthermore, according to their similarity with AtMYB genes associated with the control of anthocyanin production, ten SnMYB genes related to anthocyanin biosynthesis were speculated and chosen for further qRT-PCR analyses. The results indicated that five SnMYB genes (SnMYB75, SnMYB90, SnMYB6, SnMYB82, and SnMYB12) were expressed significantly differently in flower development stages. In conclusion, our study establishes the groundwork for understanding the anthocyanin biosynthesis of the SnMYB gene family and has the potential to enhance the breeding of S. nemorosa.

Jasmonic acid (JA) carboxyl methyltransferase (JMT), a key enzyme in jasmonate-regulated plant responses, may be involved in plant defense and development by methylating JA to MeJA, thus influencing the concentrations of MeJA in plant. In this study, we isolated the JMT gene from Salvia miltiorrhiza, an important medicinal plant widely used to treat cardiovascular disease. We present a genetic manipulation strategy to enhance the production of phenolic acids by overexpresion SmJMT in S. miltiorrhiza. Global transcriptomic analysis using RNA sequencing showed that the expression levels of genes involved in the biosynthesis pathway of phenolic acids and MeJA were upregulated in the overexpression lines. In addition, the levels of endogenous MeJA, and the accumulation of rosmarinic acid (RA) and salvianolic acid (Sal B), as well as the concentrations of total phenolics and total flavonoids in transgenic lines, were significantly elevated compared with the untransformed control. Our results demonstrate that overexpression of SmJMT promotes the production of phenolic acids through simultaneously activating genes encoding key enzymes involved in the biosynthesis pathway of phenolic acids and enhancing the endogenous MeJA levels in S. miltiorrhiza.