Phylogenetic placement and reassessment of <i>Asperisporium pongamiae</i> as <i>Pedrocrousiella</i> <i>pongamiae</i> <i>gen. et comb. nov.</i> (<i>Mycosphaerellaceae</i>)

Abstract

The leaf spot disease of Pongamia pinnata caused by an asperisporium-like asexual morph, which is usually referred to as Asperisporium pongamiae , is quite common during monsoon seasons in India. Phylogenetic analyses, based on LSU and rpb2 sequence data, and blast searches using ITS sequence data, revealed that this ascomycete forms a lineage within Mycosphaerellaceae distant from all other generic lineages. Pedrocrousiella gen. nov. , with P. pongamiae comb. nov. , based on Fusicladium pongamiae (≡ A. pongamiae ), as type species is introduced for this lineage. This species has been considered the asexual morph of Mycosphaerella pongamiae (≡ Stigmatea pongamiae ). However, this connection is unproven and was just based on the occasional association of the two taxa in some collections. Several attempts to induce the formation of a sexual morph in culture failed, therefore the putative connection between these morphs could not be confirmed. Asperisporium pongamiae-pinnatae is reduced to synonymy with P. pongamiae . Asperisporium pongamiae-pinnatae was introduced because of the wrong assumption that F. pongamiae had been described on another host, Pongamia globosa . But Fusicladium pongamiae was actually described in India on Pongamia glabra , which is a synonym of P. pinnata , and hence on the same host as Asperisporium pongamiae-pinnatae . Pedrocrousiella pongamiae clusters in a clade containing Distocercospora , Clypeosphaerella , and " Pseudocercospora " nephrolepidicola , a species which is not congeneric with Pseudocercospora . Phylogenetically, Pedrocrousiella is distant from the Asperisporium s. str. clade (type species A. caricae ), which is more closely related to Amycosphaerella , Pseudocercosporella , Distomycovellosiella and Nothopassalora .

Topics & Concepts