Legume-rhizobial Symbiosis: Progress and Prospects

Data on the role of the legume-rhizobial symbiosis (LRS) in national economic and a brief history of the fundamental study of this unique biological phenomenon are summarized. The features of the formation of root nodules of determinant and indeterminant types are described. The physiological role of the rhizobial Nod factor in suppressing the defense system of a legume plant and the role of the plant's immune systems (MTI and ETI) in the rhizobial infection and the formation of LRS are discussed. Signal systems of a legume plant (Ca2+, NO-synthase, NADPH oxidase) and their components (ROS, RNS) and other signaling molecules involved and interacting in LRS onset are described. The necessity of studying the local and systemic resistsnce of the legume plant to the rhizobial infection is emphasized

Rhythmical changes of a level nitric oxide (NO) in roots etiolated seedlings of pea (Pisum sativum L.) and influence of exogenous calcium

Studied time dynamics (during 60 mines) a level oxide nitric (NO) in cross cuts of roots 2 – day etiolated seedlings of pea sowing (Pisum sativum L.) by use of fluorescent probe DAF-2DA and a fluorescent microscope depending on action exogenous calcium (Ca2+). During an exposition of seedlings on water, solution CaCl2 are shown fluctuation in level NO in roots – his increase and decrease that testifies to the certain rhythm in generation NO. Exogenous factors (Ca2+) change time dynamics of level NO in comparison with variant “water”. Ca2+chelate EGTA removes action exogenous calcium on rhythmical change of a level NO in roots. Results are discussed in aspect of close interference of signaling systems and molecules (Ca2+, NO, Н2О2)

Physiological role of calcium in legume-rhizobium symbiosis

Literature data on the physiological role of calcium (Ca2+) in legume-rhizobium symbiosis development on initial stages - the infection and symbiotic structures formation, are generalized. The questions about the Ca2+ function in plants, special feature the formation of legume-rhizobium symbiosis and role of calcium in the interaction of two organisms are considered. Data on the interaction of ROS and Ca2+ in the development of the legume-rhizobium symbiosis and the relationship of NADPH-oxidase activity with the calcium signaling system are analyzed. The special attention is given to the role of Ca22+-spiking and calcium and calmodulin-like kinase in the initiation of plant symbiotic ways operation leads to infection and the formation of symbiotic structures