Capsicum frutescens is a valuable economic crop that is widely cultivated for its unique flavor and rich nutritional content. While some studies have shown differences in flavonoid content among different chili species, the mechanism by which changes in flavonoid composition lead to fruit color variations in C. frutescens remains underreported. We performed transcriptomics and widely targeted metabolome sequencing on three different growth stages of the C. frutescens fruit and analyzed the data to better understand the mechanism of color change. Based on previous research on the genes that regulate flavonoid compounds and the MBW complex, we have identified a total of 28 core genes related to flavonoid biosynthesis and 8 genes that may be related to flavonoid synthesis. Through extensive targeted metabolomic analysis, 581 differential metabolites were identified, including 43 flavonoids. Most anthocyanins, flavonols, and flavonoids were found to be more abundant during the immature fruit stage, which we presume is associated with the differential expression of genes involved in flavonoid biosynthesis and regulation. These findings provide a useful reference for understanding flavonoid synthesis and the accumulation of fruits in C. frutescens.

Medicago sativa is one of the world’s most important forage plants, possessing strong nitrogen-fixing and regrowth capabilities. Promoting its growth not only enhances stress resistance but also reduces the use of chemical fertilizers. The value of Centella asiatica is primarily reflected in its medicinal properties. Currently, endophytic fungal resources of C. asiatica are scarce, and their potential to promote medicinal components and the underlying mechanisms remains unclear. This study employed DNA extraction techniques to isolate and identify endophytic fungi from different parts of C. asiatica. We systematically analyzed the plant growth-promoting traits of endophytic fungi. After screening for the optimal strain and inoculating it into Medicago sativa, we elucidated the mechanisms underlying its growth-promoting effect using metabolomic sequencing. Research findings: A total of 18 endophytic fungal strains were isolated, belonging to 12 genera. Among them, five indole-3-acetic acid (IAA) strains were identified, with strain J4 demonstrating the highest IAA production (17.157 mg·L⁻¹). The J4 strain has iron-transporting carrier activity, while 15 strains exhibit nitrogen-fixing activity. Inoculation with the Plectosphaerella plurivora strain significantly increases M. sativa’s germination rate, fresh weight, dry weight, and plant height. Metabolomic analysis indicates that P. plurivora may promote anthocyanin and jasmonic acid accumulation by regulating pathways such as flavonoid biosynthesis and pyrimidine metabolism, thereby promoting growth. This study reveals the mechanism by which endophytic fungi enhance M. sativa growth at the metabolomic level. This study reveals the growth-promoting mechanism of endophytic fungi in M. sativa from a metabolomic perspective, providing a theoretical basis for increasing forage yield and offering new insights into sustainable agricultural development.

Capsicum baccatum is a close relative of edible chili peppers (Capsicum annuum) with high economic value. The CBF gene family plays an important role in plant stress resistance physiology. We detected a total of five CBF genes in the C. baccatum genome-wide sequencing data. These genes were scattered irregularly across four chromosomes. The genes were categorized into three groupings according to their evolutionary relationships, with genes in the same category showing comparable principles for motif composition. The 2000 bp upstream of CbCBF contains many resistance-responsive elements, hormone-responsive elements, and transcription factor binding sites. These findings emphasize the crucial functions of these genes in responding to challenging conditions and physiological regulation. Analysis of tissue-specific expression revealed that CbCBF3 exhibited the greatest level of expression among all tissues. Under conditions of low-temperature stress, all CbCBF genes exhibited different levels of responsiveness, with CbCBF3 showing a considerable up-regulation after 0.25 h of cold stress, indicating a high sensitivity to low-temperature response. The importance of the CbCBF3 gene in the cold response of C. baccatum was confirmed by the use of virus-induced gene silencing (VIGS) technology, as well as the prediction of its protein interaction network. To summarize, this study conducts a thorough bioinformatics investigation of the CbCBF gene family, showcases the practicality of employing VIGS technology in C. baccatum, and confirms the significance of the CbCBF3 gene in response to low temperatures. These findings provide significant references for future research on the adaptation of C. baccatum to low temperatures.