Genetic Transformation Of Resistance Genes To Maize Sheath Blight

Sheath blight is one of the major diseases of maize. It poses a serious threat to thequality and yield of maize. Currently, the few maize varieties have been found to beresistant to sheath blight and traditional breeding progress is slow. In this study, the biolistictransformation was used to overexpress with the tobacco (Nicotiana tabacum)β-1,3-glucanase gene in maize. With this, I hope to obtain transgenic lines which showresistant to sheath blight and lay a foundation for further study.The maize sheath blight is mainly caused by the Rhizoctonia solani, a serious fungalpathogen which is typically found in the soil. β-1,3-glucanases is reported to haveantifungal activity, because of the enzyme’s ability to degrade the mycelial cell wall whenthe fungus attacks the maize cell. To date, the concentration of β-1,3-glucanases in theplant is insufficient to resist the development of disease. With no natural genetic traitsconferring resistance to sheath blight, transgenic manipulation provides an obviousapproach to obtain transgenic lines with resistance to sheath blight.In this study, the tobacco β-1,3-glucanase gene and bar gene were tandemly insertedvia a T-DNA transformation vector. After selection and plant regeneration, the T1generationseeds were harvested.The independent transformation lines were obtained and confirmed by a series ofmolecular biology methods. The results of PCR and RT-PCR demonstrate that the targetgenes were introduced into the maize genome. Also the Basta solution on a leaf assay wasused to identify that the bar gene was expressed and functional. Using a Rhizoctonia solaniinoculation assay, the transgenic lines showed resistance to sheath blight. Compared withthe control, the transgenic lines had few scabs, smaller damaged leaf area and lower relativeelectrolytic leakage. The higher concentration of the β-1,3-glucanases also detected in thetransgenic plants.