Taxonomic investigation and re-assessment of some Cercosporoid fungi from India

Raghvendra Singh CS-1 Fungal systematics and diversity

Taxonomic investigation and re-assessment of some Cercosporoid fungi from India

 

Raghvendra Singh1* and Shambhu Kumar2

 

1Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi, U.P., India 221005

2Forest Pathology Department, KSCSTE-Kerala Forest Research Institute, Peechi, Thrissur, Kerala, India 680653

*Email: drsinghtaxon@gmail.com, singhr.bot@bhu.ac.in

 

Clypeosphaerella indica was discovered on living leaves of Mallotus philippensis (Euphorbiaceae). Clypeosphaerella is morphologically similar to species of Mycosphaerella s.lat., differs by having the thicker upper wall of the ascomata, resembling a pseudoclypeus. Additionally, this genus is phylogenetically distinct from other mycosphaerella-like fungi. The isolate’s morphology has similar diagnostic characters to those of Passalora and the phylogenetic analysis based on ITS placed the species in a single-strain lineage closely related to Pseudocercospora. In the present study, based on a multigene analysis (LSU-RPB2-ITS), this strain clusters among the species of Clypeosphaerella, which is closely related to Pseudocercospora. The main issue is that the previously described species in this genus, C. sticheri and C. quasiparki, are only known by their sexual morph and C. calotropidis is only known from its asexual morph. Based on the molecular and morphological data, we propose a new species in Clypeosphaerella as C. indica.

Another new hyaline cercosporoid fungus was discovered on living leaves of Tinospora cordifolia (Menispermaceae). Based on multigenes (LSU-RPB2-ITS) phylogenetical analysis, this strain represents a new lineage within Neocercosporella. Hence, a new species N. indica is proposed. Superficially, the colourless nature with thickened and darkened loci and hila make it closer to Cercosporella, but differs in having terminal and intercalary conidiogenous cells and weak catenation in conidia. Phylogenetically, Neocercosporella is distant from the Cercosporellas. str. clade (type species C. virgaureae). Phylogenetic examinations and ultrastructure of conidiogenous loci and hila of conidia of both N. indica andN. peristrophes indicate that both are congeneric. Neocercosporella can be easily distinguished from closely related members of ramularioid complex namely Cercosporella, Pseudocercosporella and Ramularia, based on the ultrastructure of their conidiogenous loci. Neocercosporella has conical loci with very small rim-like depressions on the top encircling a small, flat and protuberant-like structure. Neocercosporella produces terminal and intercalary conidiogenous cells and weak catenation of conidia.

Other two undescribed species of Zasmidium were discovered on Cassia fistula (Fabaceae) and Meyna laxiflora (Rubiaceae). These are characterized by having planate conidial scars, verruculose superficial hyphae, and solitary to rarely catenate and usually rough-walled conidia. Verruculose superficial hyphae and rough-walled conidia are characters shared by both Stenella and Zasmidium. Both these genera can be easily distinguished from each other only based on molecular analyses. The genus Stenella clusters within the Teratosphaeriaceae and characterized by pileate conidiogenous loci, while Zasmidium is distinguished by having planate Cercospora-like conidiogenous loci and belongs to the Mycosphaerellaceae.

KEYWORDS: Anamorph; Ascomycota; Dothideomycetes; New taxa; Nomenclature; Phylogeny

Raghvendra Singh (Website)

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Dr. Raghvendra Sing is presently working as an Assistant Professor at the Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University (BHU), Varanasi, UP, India since 2015. Previously he has worked as Assistant Professor in the Department of Botany, School of Biological Sciences, Dr. Harisingh Gour Central University Sagar, M.P., India during 2013-2015, Lecturer in the Department of Industrial Microbiology, DDU Gorakhpur University, Gorakhpur, U.P., India during 2009-2012, Subject Matter Specialist in the Department of Home Science, DDU Gorakhpur University, Gorakhpur, U.P., India during 2008-2009 and Lecturer in the Department of Botany, DDU Gorakhpur University, Gorakhpur, U.P., India during 2007-2008. He did his M.Sc. (Gold medalist) in Botany in 2006 and Ph.D. in Botany (Mycology) from DDU Gorakhpur University, Gorakhpur, UP, India in 2011.He has qualified CSIR National Eligibility Test (2006 & 2008) and GATE (2006 & 2010). He has discovered more than 80 fungal strains published in more than 75 research papers related to fungal diversity particularly Taxonomy and Systematics of foliicolous fungi in peer reviewed and reputed International and National Journals. Dr. Singh has participated and presented a number of papers in several National and International symposia/conferences and acquired National training /workshops on Biodiversity and molecular taxonomy as well as tissue culture. He is the Life member of a number of Mycological Society and potential reviewer of a number of International Journals (Mycotaxon, Australasian Plant Pathology, Mycological Progress, Tropical Plant Research, World Journal of Mycology, Journal of Global Plant Pathology, Agricultural Science Research Journal, Kavaka etc.). His area of Interest is Herbarium and Fungarium Techniques, Identification and exploration of Phytopathogenic fungi, Plant-Fungus Interaction, Culturing of Fungi, Characterization of potential metabolites of fungi, Molecular Taxonomy Techniques, Various tools of bio-informatics & computational biology: Primer designing, Data mining/ Biological databases, Phylogenetic analysis, Sequence analysis, Structure prediction of protein & post structural analysis etc.