Soybean leghemoglobin targeted to potato chloroplasts influences growth and development of transgenic plants

Potato tubers were transformed with a chimeric gene made by the fusion of t he soybean leghemoglobin encoding gene (lba) with the chloroplastic targeti ng sequence from Rubisco. This construct was placed under the control of th e strong constitutive 35S promoter and the 3' nontranslated region of Rubis co from pea. Leghemoglobin expression on kanamycin-resistant plants was mon itored by RT-PCR. Furthermore, immunodetection of subcellular fractions of transgenic plants revealed that leghemoglobin was imported and correctively processed inside the organelle. In addition, analysis of transgenic plants revealed reduced growth and decreased tuber production compared with the u ntransformed plants. It is suggested that leghemoglobin expression in potat o chloroplasts interferes with aerobic metabolism, leading to physiological and morphological changes.