ABSTRACT
Plants capable of stimulating the N2 fixation in the root nodules with endosymbiotic associations of actinobacteria Frankia are known as actinorhizal plants. During the signaling, molecules communicate to develop the new root organs known as actinorhizal nodules. The Frankia are capable of interacting with 225 species belonging to 8 families and 25 genera of nonleguminous plants. Among the 8 families, the Casuarinaceae are most important due to their potential effect in agriculture and other environmental applications. Casuarina is ideal for growing in polluted dry lands and rain-fed areas. It plays a role in different applications such as pulp wood, fuel wood, timber production, medical use, windbreak, sand dune stabilization, improving the soil’s physical properties and maintaining soil organic matter, and fixing atmosphere N2 with the help of Frankia. The recent reports point out that the abundance of relative Frankia populations was more in actinorhizal plants. Actinorhizal interactions display several primitive features and thus provide the ideal opportunity to determine the minimal molecular toolkit desirable to construct a nodule and to understand the evolution of root nodule symbioses. Actinorhizal nodules shares a lot of features with rhizobial nodulation, yet our understanding of the molecular mechanisms implicated in actinorhizal nodulation remain very inadequate. Therefore, the overall bacterial community (bacteriome) diversity within Casuarina root nodules documented is very fewer. In this chapter, we provide an outline on root nodule bacteriome and microbiome networks from actinorhizal Casuarina plant in different diversities along with next-generation sequencing of 16S rRNA metagenomic analysis.
