Simple experiment on legume-rhizobium symbiosis aimed at students without laboratory experience

Abstract

The curriculum for undergraduate Agricultural Engineering does not usually include much laboratory practice. In order to address this, here we propose the design of a practical class on legume-rhizobia symbiosis, using an interdisciplinary approach that takes elements from botany, agriculture, and microbiology. The students perform an assay to stimulate nodulation in chickpea seedlings through inoculation with Mesorhizobium strains recommended as commercial inoculants, and evaluate improvement in plant growth as a result of nitrogen fixation. The experiment could serve as a springboard to discuss the importance of plant-bacteria interactions in the cultivation of a regionally relevant crop. It may also encourage the use of abilities of different kinds, including the appropriate manipulation of lab materials, the active engagement of scientific thought, the application of knowledge to specific real world scenarios and collaborative teamwork, all of which will be of paramount importance throughout the students’ careers. The class can be easily adapted for other degrees connected to environmental microbiology, as well as for other symbiotic pairs that may include significant crops from other regions around the world.