Since its introduction to China in the late 16th century, Capsicum has transitioned from an exotic crop into a cornerstone of Chinese agriculture. This review examines the industry's historical dissemination and current landscape, which now spans over 2.25 million hectares and yields exceeding 64 million tons annually. This scale supports a vertically integrated value chain, ranging from germplasm breeding and regionalized cultivation to extensive primary and advanced processing. Furthermore, we analyze cultivation practices, consumption dynamics and socioeconomic implications, while offering a strategic outlook on the industry's global competitiveness. These findings highlight the integral role of Capsicum in shaping China's culinary traditions and its significance as a pivotal component of the national agricultural economy.

Leaf color is directly related to altered photosynthesis. Hence, leaf yellowing mutants can be widely used for the researching plant physiology and functional genomes, for cultivating new varieties of popular horticultural plants, and for identifying hybrid purity (as markers). Here, we constructed a ⁶⁰Co-γ F₂ population from the leaf -yellowing mutant R24 via radiation mutation with the inbred line WT21 of pepper. Genetic analysis showed that the leaf-yellowing of the mutant was controlled by a single recessive gene. By applying the Bulk Segregation Analysis and Kompetitive Allele Specific PCR markers, the leaf-yellowing gene CaLY1 (Capsicum annuum Leaf yellow 1) was mapped on chromosome 9, SNP5791587–SNP6011215, with a size of 214.5 kb. One non-synonymous mutated gene Capana09g000166 was found in the interval. The gene encoded a PsbX, which is the core complex of PSII. Transcriptome analysis further showed that 2301 differentially expressed genes were identified under shading treatment for 24 h in R24. The Gene Ontology enrichment pathways were related to photosynthesis light harvesting, cell wall, activity of quercetin 3-O-glucosyltransferase and flavonoid metabolic process, which likely regulate the response of pepper leaves to different light levels. Functional enrichment analysis indicated that the most abundant pathways were photosynthesis antenna proteins and metabolic.

The stay-green trait is of considerable importance in extending the shelf life of green pepper fruit (Capsicum annuum L.) and in enhancing the appearance of ornamental plants. The study revealed the genetic and regulatory mechanisms of the stay-green trait in pepper, which will aid in the selection of ornamental pepper varieties. In this study, a pepper mutant with stay-green fruit named TNX348 was identified from a germplasm resource bank. Two segregating populations were constructed using the stay-green mutant TNX348 and then used in bulked segregant analysis combined with RNA sequencing and linkage analyses. The causal gene of the stay-green trait was mapped to an approximately 131-kb region, and a senescence-induced chloroplast protein gene, CaSGR1 (Capana01g000359), was identified as a candidate gene. Sequencing analysis revealed a G→A single-base mutation of CaSGR1 in TNX348 that led to early termination of translation. Based on the single-base mutation, a single nucleotide polymorphism (SNP) marker co-segregating with the stay-green trait was developed. Furthermore, in transcriptome analysis, expression patterns of 11 hormone transduction-related transcription factors, such as abscisic acid-insensitive (ABI), abscisic acid-responsive element-binding factor (ABF), and NAC transcription factor, were similar or opposite to that of CaSGR1. The results indicated that the transcription factors might mediate chlorophyll degradation by regulating the expression of CaSGR1.

Genes containing GTP_EFTU domain mainly express elongation factors (EF), Small GTPases, and GTP-binding proteins, which are closely related to protein synthesis, extension and ATP synthesis. In this study, we identified 39 genes containing GTP_EFTU domains from peppers. The evolutionary trees constructed from capsicum, Arabidopsis, rice, and tomato are mainly divided into 7 subfamilies. Using PacBio (Pacific Biosciences) sequencing and assembly data, we extracted these 39 gene sequences, from which 25 genes had alternative splicing. Particularly, the Capana08g000545 had 16 alternative splicing processes. Accordingly, we performed promoter sequence analysis, subcellular location prediction, the expression analysis of different tissues and periods, and also the GO (Gene ontology) analysis of co-expressed genes. Lastly we did the qRT-PCR analysis in 5 stages of pepper fruit development. These analyses revealed important structural and functional information for the identified 39 genes that contain GTP_EFTU domains, providing important references for further follow-up experiments to verify the genes function on plants or their unique roles in peppers.

The male-sterile line has been largely used in the hybrid seed production of pepper, which can effectively improve the efficiency of hybrid seed production. However, the formation mechanism of male sterility in pepper remains unclear. In the present study, we compared the gene expression patterns between pepper cytoplasmic male sterile line 9704A and its maintainer 9704B during floral bud development using RNA sequencing technology. A total of 547976 and 2416 Differentially Expressed Genes (DEGs) were identified in the stage S1, S2 and S3, respectively, and more than 70% of the DEGs were down-regulated in the sterile line. Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed to further understand the functions of these identified DEGs. The results showed that the DEGs were mainly enriched in pathways of starch and sucrose metabolism, pentose and glucuronate interconversions. A number of genes, such as MS1, PME5, ATPB, and lots of transcription factors were found down-regulated in the sterile line, and we also identified a series of genes with large differences in expression patterns between sterile line and maintainer line. Collectively, our findings laid a foundation for further molecular breeding in pepper and provided new insights into its mechanism underlying the male sterility.