Effect of the HCT Gene on Lignin Synthesis and Fiber Development in Gossypium barbadense

Genome-wide identification and expression analysis of the BAHD gene family in Leonurus japonicus

Acylation represents a pivotal biochemical process that is instrumental in the modification of secondary metabolites throughout the growth and developmental stages of plants. The BAHD acyltransferase family within the plant kingdom predominantly utilizes coenzyme A thioester as the acyl donor, while employing alcohol or amine compounds as the acceptor substrates to facilitate acylation reactions. Using bioinformatics approaches, the LjBAHD gene family members in the genome of Leonurus japonicus (L. japonicus) were identified and characterized including gene structure, conserved motifs, cis-acting elements, and potential gene functions. To elucidate the roles of BAHD genes in various tissues of L. japonicus, the expression profiles of LjBAHD family members across different organs were scrutinized. Under drought stress treatment, some LjBAHDs were upregulation, suggesting their potential involvement in drought response. Notably, a detailed study was conducted on a specific HCT gene (i.e., LjBAHD25) within the BAHD gene family. Analysis of its expression patterns suggested a role for LjBAHD25 in the phenylpropanoid metabolism pathway in L. japonicus, contributing to the biosynthesis of secondary metabolites with unique bioactivity. The findings of this study have established a scientific foundation for the subsequent development and functional validation of the BAHD gene family in L. japonicus.

Transcriptomics and Metabolomics Reveal Biosynthetic Pathways and Regulatory Mechanisms of Phenylpropanes in Different Ploidy of Capsicum frutescens

Pepper is a significant cash crop, and Capsicum frutescens is an exemplary variety of pepper cultivated for its distinctive flavor and substantial nutritional value. Polyploidization of plants often leads to an increase in their biomass and improved stress tolerance, and thus has important applications in plant breeding and improvement. In this study, germplasm innovation was carried out by polyploidy induction of C. frutescens by colchicine. To investigate the effects of polyploidization on C. frutescens, we conducted transcriptomic and metabolomic analyses of diploids and homotetraploids of C. frutescens to gain insights into the mechanisms of metabolite composition and molecular regulation of C. frutescens by polyploidization. Based on the analysis of metabolomics and transcriptomics data, a total of 551 differential metabolites were identified in the leaves of C. frutescens of different ploidy and 634 genes were significantly differentially expressed. In comparison, 241 differential metabolites and 454 genes were significantly differentially expressed in the mature fruits of C. frutescens of different ploidy. Analysis of KEGG enrichment of differentially expressed genes and differential metabolites revealed that both differential metabolites and differentially expressed genes were highly enriched in the phenylalanine metabolic pathway. It is worth noting that phenylpropanoids are highly correlated with capsaicin synthesis and also have an effect on fruit development. Therefore, we comprehensively analyzed the phenylalanine metabolic pathway and found that chromosome doubling significantly down-regulated the expression of genes upstream of phenylalanine (PAL, 4CL), which promoted lignin accumulation, and we suggested that this might have led to the enlargement of polyploid C. frutescens fruits. This study provides some references for further research on the phenotypic traits of different ploidy of C. frutescens, cloning of key regulatory genes, and using genetic engineering techniques in C. frutescens breeding for germplasm improvement.

Identification of the function of a key gene NnHCT1 in lignin synthesis in petioles of Nelumbo nucifera

Leaf petiole or stem strength is an important agronomic trait affecting the growth of underground organs as a channel for material exchange and plays a vital role in the quality and yield of crops and vegetables. There are two different types of petioles in lotus, floating leaf petioles and vertical leaf petioles; however, the internal difference mechanism between these petioles is unclear. In this study, we investigated the differences between the initial vertical leaf petioles and the initial floating leaf petioles based on RNA sequencing (RNA-seq), and >2858 differentially expressed genes were annotated. These genes were chiefly enriched in phenylpropanoid biosynthesis, which is the source of the lignin and cellulose in petioles and stems. Lignin biology-related gene NnHCT1 was identified, and subsequent biological function validation demonstrated that the transient overexpression of NnHCT1 significantly increased the lignin and cellulose contents in lotus petioles and tobacco leaves. In contrast, silencing NnHCT1 through virus-induced gene silencing significantly reduced petiole lignin synthesis. Additionally, differentially up-regulated MYB family transcription factors were identified using RNA-seq. Yeast-one-hybrid and dual-luciferase reporter assays demonstrated that MYB4 could bind to the NnHCT1 promoter and up-regulate NnHCT1 expression. These findings demonstrate the significant potential of NnHCT1 to enhance lignin synthesis, thereby improving stem or petiole resistance to stunting and explaining the need for the study of differential petiole relationships in plants.

Effects of selenium enrichment on fermentation characteristics, selenium content and microbial community of alfalfa silage

BACKGROUND

Selenium is essential for livestock and human health. The traditional way of adding selenium to livestock diets has limitations, and there is a growing trend to provide livestock with a safe and efficient source of selenium through selenium-enriched pasture. Therefore, this study was conducted to investigate the effects of selenium enrichment on fermentation characteristics, selenium content, selenium morphology, microbial community and in vitro digestion of silage alfalfa by using unenriched (CK) and selenium-enriched (Se) alfalfa as raw material for silage.

RESULTS

In this study, selenium enrichment significantly increased crude protein, soluble carbohydrate, total selenium, and organic selenium contents of alfalfa silage fresh and post-silage samples, and it significantly decreased neutral detergent fiber and acid detergent fiber contents (p < 0.05). Selenium enrichment altered the form of selenium in plants, mainly in the form of SeMet and SeMeCys, which were significantly higher than that of CK (p < 0.05). Selenium enrichment could significantly increase the lactic acid content, reduce the pH value, change the diversity of bacterial community, promote the growth of beneficial bacteria such as Lactiplantibacillus and inhibit the growth of harmful bacteria such as Pantoea, so as to improve the fermentation quality of silage. The in vitro digestibility of dry matter (IVDMD), in vitro digestibility of acid detergent fibers (IVADFD) and in vitro digestibility of acid detergent fibers (IVNDFD) of silage after selenium enrichment were significantly higher than those of CK (p < 0.05).

CONCLUSION

This study showed that the presence of selenium could regulate the structure of the alfalfa silage bacterial community and improve alfalfa silage fermentation quality. Selenium enrichment measures can change the morphology of selenium in alfalfa silage products, thus promoting the conversion of organic selenium.