Functional study on the regulation of lignin formation and disease resistance by the CpARF22 gene in Cucurbita pepo L

• Published in: Plant physiology and biochemistry Vol. 229; no. Pt A; p. 110309
• Main Authors: Zhang, Ming-jun, Xue, Ying-yu, Qin, Yu-ling, Hu, Yu-lin, Liu, Si-yu
• Format: Journal Article
• Language: English
• Published: France Elsevier Masson SAS 01.12.2025
• Subjects: CpARF22; Hull-less Cucurbita pepo L; Lignin; Overexpression genetic transformation; Virus-induced gene silencing; Lignin; CpARF22; Overexpression genetic transformation; Virus-induced gene silencing; Hull-less Cucurbita pepo L
• ISSN: 0981-9428; 1873-2690; 1873-2690
• DOI: 10.1016/j.plaphy.2025.110309

The hull-less Cucurbita pepo L., also known as the naked-seeded pumpkin, is a relatively rare natural variant whose seeds closely resemble shelled pumpkin kernels, hence its name. The Fusarium wilt, caused by Fusarium oxysporum f. sp. cucumerinum, is a highly destructive soil-borne disease that poses a significant threat to the hull-less C. pepo industry. Therefore, delving into the disease-resistant gene resources of hull-less C. pepo is important for preventing and controlling Fusarium wilt. In this study, the CpARF22 gene was cloned from hull-less C. pepo. The expression profile and disease resistance mechanism of the CpARF22 gene were analyzed and validated through overexpression genetic transformation in Arabidopsis thaliana and Virus-Induced Gene Silencing (VIGS) technology. These approaches provided insights into the functional role of CpARF22 in conferring resistance to Fusarium wilt, contributing to the broader understanding of disease resistance mechanisms in hull-less C. pepo and offering potential strategies for crop improvement and disease management. Bioinformatics analysis revealed that the gene has a CDS length of 1953 bp, encoding 650 amino acids. Protein interaction analysis indicated that it interacts with 10 IAA proteins. An overexpression vector was constructed, and transgenic Arabidopsis plants overexpressing CpARF22 were obtained. Following inoculation with Foc, the overexpression lines displayed milder disease symptoms compared to wild-type plants, disease index decreased by 23.39 %. These plants also exhibited higher levels of photosynthetic parameters, defense enzyme activities, cell wall synthesis-related metabolites, and lignin biosynthesis-related gene expression, while malondialdehyde (MDA) and pectinase contents were lower than in wild-type plants. The staining of tissue sections further confirmed that the lignin content in overexpression lines was indeed higher than in wild-type plants. These results demonstrate that overexpression of CpARF22 enhances disease resistance. Additionally, gene-silenced plants (with a silencing efficiency of 60 %) were generated using a silencing vector. After inoculation, the silenced lines showed more severe disease symptoms and disease index increased by 45.93 %. Reduced expression of key resistance-related indicators and lignin biosynthesis genes compared to wild-type plants. Histochemical staining analysis clearly demonstrated that the lignin content in gene-silenced plants was significantly lower than that in wild-type plants. These findings further confirm the functional role of CpARF22 in conferring resistance to Fusarium wilt in hull-less C. pepo. •Unique Research Subject – Hull-less Cucurbita pepo L.•Cloning and Identification of a Key Disease Resistance Gene (CpARF22)•Comprehensive Functional Validation Using Multiple Approaches.•In-Depth Analysis of Disease Resistance Mechanisms.