Cys2/His2-type zinc finger transcription factors (C2H2 TFs) constitute one of the largest and most functionally diverse transcription factor families in plants, playing core regulatory roles in multiple aspects of plant growth, development, and stress adaptation. Based on literature data from databases including PubMed (1995–April 2026) and integrated with bioinformatics analyses, this review provides a comprehensive overview of this family. We first summarize the structural characteristics and classification systems of C2H2 TFs, and elucidate their evolutionary dynamics from lower plants to angiosperms. Regarding their impact on plant organ development, beyond key biological processes, this review details the molecular mechanisms of C2H2 TFs in floral organ morphogenesis (e.g., petal, sepal, stamen, and ovule development), pollen fertility maintenance, and flowering time regulation. Concurrently, we systematically analyze their functional pathways in responses to abiotic stresses (drought, high salinity, low temperature, aluminum toxicity, etc.) and biotic stresses (pathogens, pests), clarifying the molecular networks through which they coordinate reactive oxygen species (ROS) homeostasis, stomatal movement, and osmotic regulation by modulating hormone signaling pathways such as ABA, SA, and JA. Furthermore, this review discusses major limitations of current research, including knowledge gaps concerning functional redundancy, pseudogenization phenomena, and cell type-specific regulation. We also provide perspectives on future research directions leveraging cutting-edge technologies such as CRISPR gene editing, single-cell sequencing, and multi-omics integration, as well as their application prospects in crop stress resistance breeding and quality improvement. This review provides ideas for in-depth research on the regulatory network and related functions of C2H2 TFs, and offers reference value for improving plant traits, enhancing plant resistance, and increasing the production of plant secondary metabolites.

In recent years, copper pollution has gradually become one of the major problems of soil environmental pollution. Lignin plays an important role in plant resistance to biotic and abiotic stresses. CCoAOMT is a key enzyme in the lignin biosynthesis process. In this study, the CCoAOMT gene family members of Platycodon grandiflorus were identified by bioinformatics methods, and their basic characteristics and potential functions were analyzed. The results showed that five members of the PgCCoAOMT gene family were identified in P. grandiflorus, with protein lengths ranging from 246 to 635 amino acids, and were evenly distributed on four chromosomes. Phylogenetic analysis indicated that the PgCCoAOMT gene family was divided into two subclades, namely Clade1a, Clade1b, Clade1c, Clade1d, and Clade2. The cis-regulatory element analysis of the promoter revealed that the PgCCoAOMT members contained a large number of cis-regulatory elements responsive to stress, and conjecture PgCCoAOMT2, PgCCoAOMT4, and PgCCoAOMT5 were involved in the lignin synthesis. The qRT-PCR results showed that, within 5 days of copper stress treatment, except for the PgCCoAOMT4 gene, the other genes exhibited different expression levels. Furthermore, the expression levels of all five PgCCoAOMT genes increased significantly at 7 days of treatment. With the increase in the number of days of treatment, the content of lignin in the seedings of P. grandiflorus showed a trend of increasing first and then decreasing under copper stress. In general, in the copper stress treatment of 1–3 days, the transcriptional inhibition of PgCCoAOMT1 and PgCCoAOMT3 and the increase in lignin content contradicted each other, suggesting that there was post-translational activation or alternative metabolic pathways compensation. Meanwhile, in the 7-day treatment, the coordinated up-regulation of the genes was accompanied by the failure of lignin synthesis, which pointed to the core bottleneck of metabolic precursors depletion and enzyme activity inactivation caused by root damage. Research objective: This study reveals the expression level of the PgCCoAOMT gene in the seedings of P. grandiflorus under copper stress, providing a theoretical basis for elucidating the mechanism of P. grandiflorus response to copper stress and for subsequent improvement of root resistance in P. grandiflorus.

Copper is an essential trace element for plant growth; however, in excessive amounts, it can cause severe toxicity by inducing bursts of reactive oxygen species and disrupting metabolic balance. As a root-based medicinal plant and food, Platycodon grandiflorus has its roots in direct contact with the soil. Its ability to accumulate copper is the most pronounced among various heavy metals; consequently, it is particularly susceptible to copper stress, which in turn affects its normal growth and medicinal quality. This paper focuses on the intrinsic stress potential and possible response pathways of Platycodon grandiflorus to copper stress. Drawing on existing research and relevant literature, it conducts an integrated analysis of its defence mechanisms across four levels: physical barriers, non-enzymatic antioxidants, conserved physiological and biochemical pathways, and transcriptional regulation. Regarding physical barriers, the cell wall forms the first line of defence through pectin adsorption and lignin deposition; in terms of endogenous antioxidant defence, secondary metabolites such as polysaccharides and saponins can directly participate in the scavenging of reactive oxygen species; regarding conserved pathways, the glutathione–phytochelate system acts in concert with antioxidant enzymes such as SOD and CAT to participate in copper ion chelation and the alleviation of oxidative stress, with hormone signalling regulation also playing a crucial coordinating role in this process; regarding transcriptional regulation, transcription factors such as PgWRKY may mediate the perception of stress signals and the expression of downstream genes. These pathways act in a coordinated and sequential manner, collectively forming a multi-level defence network through which Platycodon grandiflorus responds to copper stress. At the same time, this paper highlights the functional limitations of this defence system, summarises the shortcomings in current research, and proposes directions for future studies, with a view to guiding the safe cultivation and quality assurance of Platycodon grandiflorus in copper-polluted areas, as well as for the breeding of heavy-metal-tolerant medicinal plants.

Superoxide dismutase (SOD) is a key enzyme in the plant antioxidant system. It plays an essential role in plant adversity stress by scavenging excess reactive oxygen species to protect cells from oxidative damage. Isatis indigotica, being a mildly saline-tolerant plant, can be grown in soils containing a certain amount of saline–alkaline content. In order to reveal the SOD gene family members and their potential roles under saline and alkaline stress, the present study used a bioinformatics approach to identify 9 potential IiSOD genes in the I. indigotica genome. It analyzed the expression patterns of SOD family genes (IiSODs) in response to alkaline stress. According to the results of quantitative real-time PCR (qRT-PCR), the expression levels of the IiSOD7 gene significantly increased within 120 h of alkaline stress treatment, while the expression level of the IiSOD8 gene was the highest among all detected genes at 120 h of alkaline stress. The rest of the genes showed different degrees of expression. Alkaline stress showed significant and dynamic changes in the content of indigo and indirubin in leaves of I. indigotica. Finally, the yeast one-hybrid assay confirmed that IiWRKY54 was able to activate the expression of IiSOD2 and IiSOD7. Combined with qRT-PCR analysis, it was further hypothesized that IiWRKY54 might enhance the alkaline tolerance of I. indigotica by regulating the expression of IiSOD2 and IiSOD7. Taken together, this study lays the foundation for elucidating the function of the IiSOD gene in salinity stress tolerance of I. indigotica as well as promoting the genetic breeding of alkaline-tolerant varieties of I. indigotica.

Caffeoyl CoA O-methyltransferase (CCoAOMT) is one of the key regulatory enzymes in the lignin biosynthesis pathway. In addition, it participates in the modification of flavonoids, which significantly impacts plant growth, development, and antioxidant capacity, and it plays a crucial role in plant responses to stress and adversity. There is a current research gap in the CCoAOMT gene family of Isatis indigotica, particularly in terms of systematic identification and functional validation. Therefore, this study employed bioinformatics techniques to determine the composition of the CCoAOMT gene family in the Isatis indigotica genome. Eight members of the IiCCoAOMT gene family were identified, and their gene structures and motifs are relatively conserved. These members of the IiCCoAOMT family are located on three different chromosomes (3, 6, and 7) and exhibit significant tandem replication. According to phylogenetic research, IiCCoAOMT is divided into four distinct groups: Ia, Ib, Ic, and II. It is worth noting that the IiCCoAOMT genes in group Ia may be candidate genes involved in flavonoid biosynthesis and indirectly affect the content of flavonoid components., Subsequently, a yeast one-hybrid experiment verified that IiWRKY48 and IiWRKY54 could activate the CCoAOMT gene promoter in Isatis indigotica. These results provide a theoretical basis for understanding the function of CCoAOMT genes.