The Genus Ravenelia: Insights on Taxonomy, Diversity and Distribution

Ravenelia is the third largest rust genus of the order Pucciniales with more than 200 described species. It is an important rust genus that has undergone tremendous taxonomic changes. This genus produces teliospores united into a head on a compound pedicel composed of two to several hyphae with autoecious, macro-, demi- to hemi-, and, more rarely, microcyclic modes of their life cycle which provide it a unique identity and have proved helpful in the identification of the genus. The current understanding of the taxonomy, history, diversity and distribution of this genus is discussed in this paper. Both online and offline resources were searched to gather data of the published literature. The data thus obtained were analyzed for numerical and graphical summaries to provide the diversity and distribution of the genus. In addition, a phylogenetic analysis based on the ITS and nLSU DNA sequence data available in GenBank and the published literature was performed to examine the taxonomic placement of different species within the genus. The genus was reported to be distributed over 53 countries of the world. Around 51 plant genera belonging to four plant families, viz., Fabaceae, Phyllanthaceae, Asphodelaceae and Zygophyllaceae were found to be infected with these rust fungi. The phylogenetic analysis based on LSU and ITS sequence data revealed the polyphyletic nature of the genus. A table of 248 species of this genus is also provided with all information of host, distribution and cited reference that can be helpful for mycologists to find all information at one place. Future perspectives for the advancement of this genus are also discussed.