Induction of signals in Mesorhizobium cicerii - Cicer arietinum L. interaction

Abstract

Chickpea is a grain legume of exceptionally high nutritive value and most versatile food used. It is mostly grown under rainfed conditions in arid and semi-arid areas around the world. Chickpea is the third most cultivated grain legume in the world. Like most legumes, it is associated in symbiosis with bacteria from the rhizobia family, which guarantee much of the nitrogen it needs for its growth and development. In early stages of the symbiosis, a complex molecular dialogue takes place, involving Nod factors synthesized by the bacterium and flavonoids released by legume roots, so that both partners can recognize each other and initiate nodulation. This work aimed to evaluate the production of the induced signals in Mesorhizobium cicerii strain and the impact of that induction on chickpea nodulation and yield. The lipid fraction in the inocula was extracted with n-butanol and analyzed by high performance liquid chromatography and gas chromatography coupled to a mass spectrometer. A higher amount of lipochitooligosaccharides (nodulation factors) and high molecular weight fatty acids were detected in daidzein-induced inocula. Similarly, the inoculums induced with this flavonoid showed a positive effect on nodulation and yield of chickpea in semicontrolled and field conditions, respectively.