Harsh environmental factors have continuous negative effects on plant growth and development, leading to metabolic disruption and reduced plant productivity and quality. However, filamentation temperature-sensitive H protease (FtsH) plays a prominent role in helping plants to cope with these negative impacts. In the current study, we examined the transcriptional regulation of the CaFtsH06 gene in the R9 thermo-tolerant pepper (Capsicum annuum L.) line. The results of qRT-PCR revealed that CaFtsH06 expression was rapidly induced by abiotic stress treatments, including heat, salt, and drought. The CaFtsH06 protein was localized to the mitochondria and cell membrane. Additionally, silencing CaFtsH06 increased the accumulation of malonaldehyde content, conductivity, hydrogen peroxide (H₂O₂) content, and the activity levels of superoxide dismutase and superoxide (·O₂⁻), while total chlorophyll content decreased under these abiotic stresses. Furthermore, CaFtsH06 ectopic expression enhanced tolerance to heat, salt, and drought stresses, thus decreasing malondialdehyde, proline, H₂O₂, and ·O₂⁻ contents while superoxide dismutase activity and total chlorophyll content were increased in transgenic Arabidopsis. Similarly, the expression levels of other defense-related genes were much higher in the transgenic ectopic expression lines than WT plants. These results suggest that CaFtsH06 confers abiotic stress tolerance in peppers by interfering with the physiological indices through reducing the accumulation of reactive oxygen species, inducing the activities of stress-related enzymes and regulating the transcription of defense-related genes, among other mechanisms. The results of this study suggest that CaFtsH06 plays a very crucial role in the defense mechanisms of pepper plants to unfavorable environmental conditions and its regulatory network with other CaFtsH genes should be examined across variable environments.

Cabbage (Brassica oleracea L. var. capitata) is an excellent source of glucosinolates (GLS) that could reduce the risk of chronic diseases. The purpose of this study was to investigate the biological traits, pigment contents, color, and GLS content of 13 cabbage varieties. This study found that there were significant differences in the GLS content for various developmental stages of cabbage varieties, and the accumulation of GLS in young leaves was higher than that in mature stages. In most of the samples, the GLS content accumulated in different parts and changed as inner leaf > middle leaf > condensed stem > root. Double haploids of the M18-15 variety may be good candidates for future breeding programs and consumers, due to their high GLS content (ranging from 201.10 to 396.25 nmol mg⁻¹ FW). GLS also act as a defense substance, and the data related to GLS accumulation patterns in different leaf locations and root parts may be useful for understanding leaf defense mechanisms and potential source–sink relationships. In addition, the observed interspecific variability is beneficial for breeders to develop Brassica varieties with high GLS content, as well as for the development of new functional food additives.

Orange Chinese cabbage (Brassica rapa L. ssp. pekinensis) is an excellent source of health-promoting nutrients that could reduce the risk of chronic diseases. This study mainly investigated the accumulation patterns of eight lines of orange Chinese cabbage for indolic glucosinolates (GLSs) and pigment content from representative plant organs across multiple developmental stages. The indolic GLSs were highly accumulated at the rosette stage (S2), especially in inner and middle leaves, and the order of indolic GLSs accumulation in non-edible organs was flower > seed > stem > silique. The expression levels of biosynthetic genes in light signaling, MEP, carotenoids, and GLS pathways were consistent with the metabolic accumulation patterns. The results of a principal component analysis show a clear separation of high indolic GLS lines (15S1094 and 18BC6) from low indolic GLS lines (20S530). A negative correlation between the accumulation of indolic GLS and carotenoids was identified in our study. Our work contributes to providing valuable knowledge required to breed, grow, and select orange Chinese cabbage varieties and their eatable organs with higher nutritional value.