Transgenic Indian mustard (Brassica juncea) expressing tomato glucanase leads to arrested growth of Alternaria brassicae

• Published in: Plant cell reports Vol. 26; no. 2; pp. 247 - 252
• Main Authors: Mondal, Kalyan K, Bhattacharya, R. C, Koundal, K. R, Chatterjee, S. C
• Format: Journal Article
• Language: English
• Published: Berlin Berlin/Heidelberg : Springer-Verlag 01.02.2007; Springer; Springer Nature B.V
• Subjects: Alternaria; Alternaria - growth & development; Alternaria brassicae; Alternaria leaf spot; Biological and medical sciences; Biotechnology; Brassica juncea; Cellulase - genetics; Cellulase - metabolism; Crop diseases; Crops; Fundamental and applied biological sciences. Psychology; Fungi; Gene Expression Regulation, Plant; Genes, Plant; Genetic engineering; Genetic technics; Glucanase; Leaves; Lycopersicon esculentum; Lycopersicon esculentum - enzymology; Lycopersicon esculentum - genetics; Methods. Procedures. Technologies; Mustard Plant - genetics; Mustard Plant - microbiology; Pathogens; Plants, Genetically Modified - microbiology; Tomatoes; Transgenic animals and transgenic plants; Transgenic plants; Plant pathogen; Enzyme; Alternaria leaf spot; Plant leaf; Pathogenesis related protein; Fungi; Resistance; Alternaria brassicae; Cruciferae; Dicotyledones; Glycosidases; Indian mustard; Angiospermae; Lycopersicon esculentum; Hydrolases; Spermatophyta; Transgenic plant; Fungi Imperfecti; Solanaceae; O-Glycosidases; Transgenesis; Thallophyta; Brassica juncea; Glucanase
• ISSN: 0721-7714; 1432-203X
• DOI: 10.1007/s00299-006-0241-3

Brassica juncea is an important oilseed crop of the Indian sub-continent. Yield loss due to fungal disease alternaria leaf spot caused by Alternaria brassicae is a serious problem in cultivation of this crop. Nonavailability of resistance genes within crossable germplasms of Brassica necessitates use of genetic engineering strategies to develop genetic resistance against this pathogen. The pathogenesis related (PR) proteins are group of plant proteins that are toxic to invading fungal pathogens, but are present in plant in trace amount. Thus, overexpression of PR proteins leads to increased resistance to pathogenic fungi in several crops. The PR protein glucanase hydrolyzes a major cell-wall component, glucan, of pathogenic fungi and acts as a plant defense barrier. We report the expression of a class I basic glucanase gene, under the control of CaMV 35S promoter, in Indian mustard and its genetic resistance against alternaria leaf spot. Southern and Northern hybridization confirmed stable integration and expression of the glucanase gene in mustard transgenics. Several independent transgenics were screened in vitro and under poly house conditions for their resistance against Alternaria brassicae. In an in vitro antifungal assay, transgenics arrested hyphal growth of Alternaria brassicae by 15-54%. Under pathogen-challenged conditions in poly house, the transgenics showed restricted number, size and spread of lesions caused by Alternaria brassicae. Also, the onset of disease was delayed in transgenics compared to untransformed parent plants. The results demonstrate potentiality of a PR protein from a heterologous source in developing alternaria leaf spot resistance in Indian mustard.