Genome-Wide Identification and Expression Analysis of TPS Gene Family in Liriodendron chinense

The regulatory landscape of β-caryophyllene biosynthesis in pak choi

β-Caryophyllene is a key volatile sesquiterpene involved in plant defense and contributes to the characteristic aroma of pak choi (Brassica campestris). This study aimed to elucidate the regulatory landscape of β-caryophyllene biosynthesis in pak choi to understand the genetic and molecular mechanisms controlling the production of this volatile sesquiterpene. Among 61 germplasm accessions of pak choi, β-caryophyllene was detected in only 11 accessions. Genetic analysis revealed that β-caryophyllene production is controlled by a single dominant gene. Fine mapping and gene sequencing identified the candidate gene B. campestris terpene synthases 21 (BcTPSa21), which encodes a β-caryophyllene synthase. Functional validation of BcTPSa21 through transient expression of BcTPSa21 in Nicotiana benthamiana leaves and enzyme activity assays in vitro confirmed its role in β-caryophyllene biosynthesis. A single nucleotide polymorphism (SNP) (C-T) in the promoter region of BcTPSa21 was found to affect the binding of the transcription factor BcMYC2, thereby influencing gene expression. Additionally, BcDIVARICATA (an R-R-type MYB TF BcDIV) was identified as a negative regulator of β-caryophyllene synthesis. The molecular experiments showed that abscisic acid participates in the biosynthesis of β-caryophyllene via the B. campestris pyrabactin resistance 1-like (BcPYL6)-BcDIVARICATA-BcMYC2 module. RNA-seq analysis suggested that under temperature stress, the transcription of BcTPSa21 and the biosynthesis of β-caryophyllene were the collective result of multilevel regulation. These findings provide comprehensive insights into the regulatory mechanisms governing β-caryophyllene biosynthesis in pak choi, identifying key factors and regulatory modules involved and offering a foundation for enhancing the flavor quality of pak choi through targeted genetic interventions.

Genome-wide identification and tissue expression pattern analysis of TPS gene family in soybean (Glycine max)

The terpene synthase (TPS) plays a pivotal roles in plant growth, development, and enhancing resilience against environmental stresses. Despite this, the bioinformatics analysis of the TPS family gene in soybean (Glycine max) is lacking. In this study, we investigated 36 GmTPS members in soybean, exhibiting a diverse range of protein lengths, spanning from 144 to 835 amino acids. A phylogenetic tree was constructed from these GmTPS genes revealed a classification into five distinct subgroups: Group1, Group2, Group3, Group4 and Group5. Notably, within each subgroup, we identified the motifs of GmTPS proteins were similar, although variations existed among different subfamilies. Gene duplication events analysis demonstrated that TPS genes expand differently in G. max, A. thaliana and O. sativa. Among, both tandem duplication and Whole genome duplication contributive to the expansion of TPS genes in G. max, and Whole genome duplication played a major role. Moreover, the cis-element analysis suggested that TPS is related to hormone signals, plant growth and development and environmental stress. Yeast two-hybrid (Y2H) assay results indicated TPS protein may form heterodimer to function, or may form complex with P450 proteins to function. RNA-seq results revealed a higher expression of most GmTPS genes in flowers, suggesting their potential contribution to flower development. Collectively, these findings offer a provide a holistic knowledge of the TPS gene family in soybean and will facilitate further characterization of TPSs effectively.

Overexpression of the Liriodendron tulipifera TPS32 gene in tobacco enhances terpenoid compounds synthesis

Liriodendron, a relic genus from the Magnoliaceae family, comprises two species, L. tulipifera and L. chinense. L. tulipifera is distinguished by its extensive natural distribution in Eastern North America. Conversely, L. chinense is nearing endangerment due to its low regeneration rate. A pivotal aspect in the difference of these species involves terpenoids, which play crucial roles in plant growth and attracting pollinators. However, the complex molecular mechanisms underlying terpenoid roles in Liriodendron are not well understood. Terpene Synthases (TPS) genes are widely reported to play a role in terpenoid biosynthesis, hence, this study centers on TPS genes in Liriodendron spp. Employing multiple bioinformatics methods, a differential expression gene in L. tulipifera, LtuTPS32, was discerned for further functional analysis. Subcellular localization results reveal the involvement of LtuTPS32 in chloroplast-associated processes, hence participate in terpenoid biosynthesis within chloroplasts. Heterologous transformation of the LtuTPS32 gene into tobacco significantly elevates the levels of common terpenoid compounds, including chlorophyll, gibberellin, and carotenoids. Collectively, these findings not only underscore the role of the LtuTPS32 gene in the biosynthesis of terpenoids but also lay a foundation for future research on interspecific differences in Liriodendron.

The Identification and Expression Analysis of the Liriodendron chinense F-Box Gene Family

The F-box gene family is one of the largest gene families in plants, and it plays a crucial role in regulating plant development, reproduction, cellular protein degradation, and response to biotic and abiotic stresses. Despite their significance, a comprehensive analysis of the F-box gene family in Liriodendron chinense and other magnoliaceae species has not been reported. In this study, we report for the first time the identification of 144 full-length F-box genes in L. chinense. Based on specific domains and phylogenetic analyses, these genes were divided into 10 distinct subfamilies. We further analyzed their gene structure, conserved domain and chromosome distribution, genome-wide replication events, and collinearity. Additionally, based on GO analysis, we found that F-box genes exhibit functional specificity, with a significant proportion of them being involved in protein binding (GO:0005515), suggesting that F-box genes may play an important role in gene regulation in L. chinense. Transcriptome data and q-PCR results also showed that F-box genes are involved in the development of multiple tissues in L. chinense, regulate the somatic embryogenesis of Liriodendron hybrids, and play a pivotal role in abiotic stress. Altogether, these findings provide a foundation for understanding the biological function of F-box genes in L. chinense and other plant species.