Improved resistance to insects in maize (Zea mays L) and cowpea (Vigna unguiculata L)

Abstract

A novel alteration in secondary metabolism of maize transformed with wheat oxalate oxidase gene (OXO) was determined using HPLC and microscopy. Phenolic concentration was significantly increased, but DIMBOA synthesis was down-regulated. The high levels of soluble phenolic acids, in particular free ferulic acid, most likely contributed to the insect resistance in the OXO maize. To facilitate future cowpea transformation with the OXO, a stable in vitro regeneration system was established in blackeye cowpea via shoot organogenesis. The optimal initiation medium comprised MS salts, B 5 vitamins, 2 mg 1-1 BAP, 3% sucrose and 0.8% agar at pH 5.8. The highest initiation frequency and shoot number were obtained from the shoot apices of 3-5 days old seedlings. For shoot elongation, 0.5-5.0 mg 1-1 GA3 was required. Rooting medium was MS salts supplemented with B5 vitamins, 3% sucrose and 0.8% agar.