Increased resistance to fusarium wilt in transgenic tobacco lines co-expressing chitinase and wasabi defensin genes

• Published in: Plant pathology Vol. 60; no. 2; pp. 221 - 231
• Main Authors: Ntui, V.O, Azadi, P, Thirukkumaran, G, Khan, R.S, Chin, D.P, Nakamura, I, Mii, M
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.04.2011; Blackwell; Wiley Subscription Services, Inc
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; Biotechnology; ChiC gene; Chitinase; Chromosome rearrangements; Colonization; Defensins; Fundamental and applied biological sciences. Psychology; Fungal plant pathogens; Fusarium oxysporum; Fusarium oxysporum f.sp. nicotianae; Genetic engineering; Genetic engineering applications; Genetic technics; Genetics and breeding of economic plants; gene‐stacking; Infection; Leaves; marker‐free; MAT vector; Methods. Procedures. Technologies; Mycelia; Nicotiana tabacum; Phytopathology. Animal pests. Plant and forest protection; Plant breeding: fundamental aspects and methodology; Plant protection; retransformation; Roots; Shoots; Streptomyces griseus; Survival; Tobacco; Transformation; Transgenic animals and transgenic plants; Transgenic plants; Wilt; Chitinase; Biotechnology; Plant pathology; nicotianae; Marker-free; Peptides; Plant pathogen; Stimulant plant; Nicotiana tabacum; Antimicrobial agent; Fusarium oxysporum f.sp; Fungi; Gene; Dicotyledones; retransformation; Angiospermae; MAT vector; Transgenic plant; Fungi Imperfecti; Solanaceae; C3-Type; Vector; Vegetals; Fusarium oxysporum; Enzyme; Biochemical compound; gene-stacking; Fungus resistance; Glycosylases; Gene flow; Sensitivity resistance; Polypeptide; Glycosidases; Hydrolases; Spermatophyta; Genetic engineering; Genetically modified organism; Defensin
• ISSN: 0032-0862; 1365-3059
• DOI: 10.1111/j.1365-3059.2010.02352.x

Marker-free transgenic tobacco (Nicotiana tabacum) lines containing a chitinase (ChiC) gene isolated from Streptomyces griseus strain HUT 6037 were produced by Agrobacterium-mediated transformation. One marker-free transgenic line, TC-1, was retransformed with the wasabi defensin (WD) gene, isolated from Wasabia japonica. Of the retransformed shoots, 37% co-expressed the ChiC/WD genes, as confirmed by western and northern analyses. Southern blot analysis showed that no chromosomal rearrangement was introduced between the first and the second transformation. Transgenic lines either expressing ChiC or WD, or co-expressing both genes were challenged with Fusarium oxysporum f.sp. nicotianae (Fon). Assessment of in vitro plant survival in the presence of Fon showed that transgenic lines co-expressing both genes had significantly enhanced protection against the fungus (infection indices 0·0-1.·2) compared with corresponding isogenic lines expressing either of the genes (infection indices 2·5-9·8). Whole-plant infection indices in transgenic lines were significantly related (r = 0·93, P < 0·01) to the extent of root colonization of the host, which ranged from 2·1% to 11·3% in lines co-expressing both genes, and from 16·8% to 37·7% in lines expressing just one of the genes (compared with 86·4% in non-transformed controls). Leaf extracts of transgenic lines also inhibited mycelial growth of Fon in vitro and caused hyphal abnormalities.