The need to carry out re-inventory of plant pathogenic fungi

Abstract

OUTLINEPlant pathogenic fungi have long been documented through concerted efforts of mycologists and plant pathologists; these records have served as the basis for regional and countrywide checklists which have since been put into databases listing hosts and associated fungi. They are used by governments and scientists to formulate trade quarantine policies and determine research funding, such as in plant breeding programs and disease control. With the ability to use molecular characters to study the systematics of fungi it is clear that morphologically defined species are often large complexes comprised of genetically and biologically distinct species. Use of molecular techniques to examine species complexes has revealed cryptic species in many important plant pathogenic genera, e.g. Botryosphaeria, Colletotrichum, Fusarium, and Mycosphaerella. It has occurred to such an extent that existing checklists and databases need updating. It is important that the data from these studies, including changes in taxonomy and nomenclature, be incorporated into the databases of plant pathogenic fungi to support accurate plant quarantine decisions. In addition, epitypifying fungi by re-collecting material from type habitats and isolating the organism into pure culture will provide essential materials for systematics studies to further clarify the taxonomy and phylogeny of plant pathogenic fungi. Overall, we conclude that disease lists are likely to be highly outdated and advocate the need for countrywide re-inventory of plant pathogens. As a result of these studies, tools can be developed that use morphological or molecular characters, or both, to promote accurate identification of plant pathogenic fungi.

The etiological agent of cotton ramulosis represents a single phylogenetic lineage within the Colletotrichum gloeosporioides species complex

“…This complex is composed of species that share common morphological traits and form a strongly supported monophyletic group, as determined by independent studies (Cai et al, 2011;Cannon et al, 2012;Weir et al, 2012). Multilocus phylogenies, inferred from DNA sequences of reference strains and newly collected isolates from different hosts and geographic regions, allowed the recent recognition of more than 20 phylogenetic species inside the C. gloeosporioides species complex .…”

“…Colletotrichum gossypii is also of quarantine importance in Europe (EPPO, 2009). Blotter tests are used routinely to detect the ramulosis pathogen on seeds (Tanaka et al, 1996); however, morphological markers of the cultures from the blotter tests do not suffice for reliable identification within the current species concept in Colletotrichum (Cai et al, , 2011Cannon et al, 2012). Due to the economic importance of ramulosis, and the apparent restricted biogeographical distribution of its etiological agent, improved quarantine legislation and disease risk assessment depend on the correct identification of the pathogen based on molecular phylogenetics (Cai et al, 2011).…”

Notes on Ceratocystis paradoxa causing internal post-harvest rot disease on immature coconut in Brazil

“…As no DNA sequences of this species collected in Brazil were available in Genbank to check whether the taxon belongs to C. paradoxa (Harrington, 2009), it was decided to identify this isolate based on multilocus phylogenetic tools (Cai et al, 2011a;2011b;Hyde et al, 2010). Despite the fact that van Wyk et al (2009) have not provided evidence that their identifications of cultures CMW 8779 and CMW 8790 were based on morphology or on type (ex-type), our study support its identification of C. paradoxa (Figure 2).…”

New species and notes of Colletotrichum on daylilies (Hemerocallis spp.)

“…One new species is proposed. Several studies have shown the importance of using sequence data when identifying Colletotrichum species, because wrong diagnosis may otherwise result Damm et al, 2010;Cai et al, 2011;Ko Ko et al, 2011).…”