Development of <i>Trichoderma harzianum</i> endochitinase gene construct conferring antifungal activity in transgenic tobacco

Abstract

199-206Trichoderma harzianum is a popular biocontrol agent used extensively against phytopathogenic fungi. The mode of action of this fungus is through secretion of cell wall degrading enzymes including chitinases. Thus, the chitinase genes isolated from T. harzianum have been successfully utilized in the production of transgenic plants with enhanced resistance to several fungi. The stringent rules of IPR necessitates that genes are cloned and constructs are developed from the local isolates of this fungus. In view of which full length chitinase gene was isolated and a construct was developed under the expression of constitutive promoter CaMV 35S for use in plant transformation. Expression of chitinase gene in transgenic tobacco plants was found to be higher as revealed by the endochitinase assay and relative quantitative RT-PCR. Its efficacy in inhibiting the fungal growth was also reported in vitro as well as in vivo in the detached leaves of tobacco transformants containing the gene. Thus, the development of T. harzianum chitinase gene construct (pIIHR-Th-Chit) would facilitate the exchange of the construct amongst researchers in the country for the development of fungus resistant transgenic plants