The expansion of <I>Phytophthora</I> clade 8b: three new species associated with winter grown vegetable crops

Abstract

Despite its association with important agricultural crops, Phytophthora clade 8b is a poorly studied group of species. The clade currently consists of three officially described species (Phytophthora porri, P. brassicae and P. primulae) that are host-specific pathogens of leek, cabbages and Primula spp., respectively. However, over the past few decades, several other clade 8b-like Phytophthoras have been found on a variety of different host plants that were all grown at low temperatures in winter seasons. In this study, a collection of 30 of these isolates was subjected to a phylogenetic study using two loci (the rDNA ITS region and the mitochondrial cox1 gene). This analysis revealed a clear clustering of isolates according to their host plants. To verify whether these isolates belong to separate species, a detailed morphological study was conducted. On the basis of genetic and morphological differences and host specificity, we now present the official description of three new species in clade 8b: Phytophthora cichorii sp. nov., P. dauci sp. nov. and P. lactucae sp. nov. Two other groups of isolates (Phytophthora taxon castitis and Phytophthora taxon parsley) might also represent new species but the data available at this time are insufficient for an official description. This brings Phytophthora clade 8b to a group of six species that are all host-specific, slow-growing and specifically infect herbaceous crops at low temperatures.

Biosynthesis, Chemical Structure, and Structure-Activity Relationship of Orfamide Lipopeptides Produced by Pseudomonas protegens and Related Species

“…M. oryzae isolate VT5M1 (Thuan et al, 2006 ) was cultured on complete medium (CM) (Talbot et al, 1993 ). Phytophthora porri isolate CBS 127099 was maintained on V8 agar (Bertier et al, 2013 ). R. solani AG 4-HGI isolate CuLT-Rs36 (Nerey et al, 2010 ) and Pythium ultimum were routinely cultivated on potato dextrose agar (PDA; Difco).…”

Phytophthora austrocedri in Argentina and Co-Inhabiting Phytophthoras: Roles of Anthropogenic and Abiotic Factors in Species Distribution and Diversity

“…Other species rarely detected in this study were P. primulae (site 1) in subclade 8b, and P. pseudocryptogea (site 1) in subclade 8a [22]. Species in subclade 8b are host specific, slow-growing, and specifically infect herbaceous crops at low temperatures [65,90], while P. pseudocryptogea and its close relatives have been isolated from soil, irrigation water, and numerous hosts [65,69,91]. The biological significance of the presence of these species in Patagonia deserves further studies.…”

One stop shop: backbones trees for important phytopathogenic genera: I (2014)

“…Additional species have recently been described; P. lacustris (Nechwatal et al 2012) P. pluvialis (Reeser et al 2013), P. mississippiae , P. cichorii, P. dauci and P. lactucae (Bertier et al 2013), P. pisi (Heyman et al 2013), P. stricta and P. macilentosa ) and the hybrid species P. x serendipita and P. x pelgrandis (Man in 't Veld et al 2012), bringing the total to at least 128 described species. With the number of provisional species names used in the literature, and research efforts to evaluate the distribution of this genus in natural ecosystem, this number is likely to continue to increase in the future.…”