Enhancement of resistance against fungal pathogens in peanut (Arachis hypogaea L.) cultivar L14 by heterologous expression of gene encoding chitinase 42 kDa from Trichoderma asperellum SH16

• Published in: South African journal of botany 2023-09, Vol.160, p.673-681
• Main Authors: Hoa, Phung Thi Bich, Tue, Nguyen Hoang, Trang, Huynh Thi Quynh, Thu, Hoang Anh, Nhung, Le Ngoc Huyen, Luong, Nguyen Ngoc, Huy, Nguyen Xuan, Tien, Nguyen Quang Duc, Loc, Nguyen Hoang
• Format: Article
• Language: English
• Subjects: Agrobacterium tumefaciens; Arachis hypogaea; Chi42; Chitinase 42 kda; Root-specific promoter; Trichoderma asperellum
• ISSN: 0254-6299
• DOI: 10.1016/j.sajb.2023.07.056

•This is the first study that successfully expressed genes encoding chitinase 42 kDa from trichoderma asperellum SH16 in peanuts (Arachis hypogaea) cultivar L14 through agrobacterium tumefaciens-mediated transformation.•Two synthetic genes (syncodChi42–1 and syncodChi42–2) optimized for codon usage for plant expression proved to be more efficient than their original gene (Chi42) from T. asperellum SH16 in transgenic peanuts.•The high expression level of two synthetic genes in peanut roots as well as their strong resistance to sclerotium rolfsii promise potential applications in the field of transgenic crops against phytopathogenic fungi. This study aims to extracellularly express the 42 kDa chitinase from Trichoderma asperellum SH16 in peanut (Arachis hypogaea) roots under the regulation of a tissue-specific Asy promoter and the driving of the signal peptide of the rice amylase 3D gene. The 42 kDa chitinase genes were employed in this study, which included one wild-type sequence (Chi42) and two synthetic sequences (syncodChi42–1 and syncodChi42–2) optimized for codon usage for plant expression. From 102 42 kDa chitinase transgenic peanut lines, seven elite lines were discovered, among them two for syncodChi42–1, three for syncodChi42–2, and two for Chi42. The study also revealed chitinase from two synthetic genes had higher expression levels than chitinase from the wild-type gene, with the highest specific activities of approximately 901 U/mg and 1124 U/mg, respectively, compared to 739 U/mg. All seven elite transgenic peanut lines exhibited strong extracellular chitinase activity, and some of them were able to fight the soil-borne pathogenic fungus Sclerotium rolfsii in both in vitro and in vivo assays. The significant chitinase activity of seven elite transgenic peanut lines, particularly five lines carrying one of two synthetic genes, suggests that transgenic crops might be used to prevent phytopathogenic fungi.