Phylogeny of ambrosia beetle symbionts in the genus Raffaelea

Abstract

The genus Raffaelea was established in 1965 when the type species, R. ambrosia, a symbiont of Platypus ambrosia beetles was described. Since then, many additional ambrosia beetle symbionts have been added to the genus, including the important tree pathogens R. quercivora, R. quercus-mongolicae, and R. lauricola, causal agents of Japanese and Korean oak wilt and laurel wilt, respectively. The discovery of new and the dispersal of described species of Raffaelea to new areas, where they can become invasive, presents challenges for diagnosticians as well as plant protection and quarantine efforts. In this paper, we present the first comprehensive multigene phylogenetic analysis of Raffaelea. As it is currently defined, the genus was found to not be monophyletic. On the basis of this work, Raffaelea sensu stricto is defined and the affinities of undescribed isolates are considered. KeywordsRaffaelea sensu stricto; Ophiostomatales; internal transcribed spacer region; ITS; ambrosia fungi; wilt pathogens 2 Research highlights Raffaelea as it is currently defined is not monophyletic. Raffaelea sensu stricto is defined. Raffaelea spp. isolates with unclear affinities are identified.

New species of Ophiostomatales from Scolytinae and Platypodinae beetles in the Cape Floristic Region, including the discovery of the sexual state of Raffaelea

“…The phylogenetic placement of these two OTUs were further investigated using βT and CAL Dreaden et al (2014) showed that Raffaelea is not monophyletic as was suggested by Harrington et al (2010). Conidiophores hyaline, (6.6-) 7.1-8.9 (-9.2) µm long, (0.3-) 0.7-1.1 (-1.5) µm wide ( Fig.…”

Laurel Wilt in Natural and Agricultural Ecosystems: Understanding the Drivers and Scales of Complex Pathosystems

“…These analyses are aided by recently published phylogenies of Raffaelea [101,102], which have identified the closest, extant relatives of R. lauricola; notably, all other members of the phylogenetic clade in which R. lauricola resides (Raffaelea sensu stricto) are not plant pathogens. Of particular interest are genome-wide comparisons between R. lauricola and its close relative R. aguacate D. R. Simmons, Dreaden and Ploetz.…”

“…The family represents some of the earliest angiosperms and has a fossil record dating back to the Mid-Cretaceous [105]. It is well represented on both sides of the Pacific Basin, and the so-called "amphi-Pacific tropical disjunction" of the Persea and Cinnamomum groups in the family has been examined to understand the presence, and the origins and relatedness, of family members in the Eastern and Western Hemispheres [101,106,107].…”

New Raffaelea species (Ophiostomatales) from the USA and Taiwan associated with ambrosia beetles and plant hosts

“…Harrington et al 2010). However, more recent and comprehensive analyses (de Beer & Wingfield 2013, Dreaden et al 2014, Musvuugwa et al 2015) have shown that Raffaelea species constitute three clades in the order, Raffaelea s. str. , the R. lauricola complex, and the R. sulphurea complex.…”

“…Raffaelea lauricola, the eponymous member of the R. lauricola complex (de Beer & Wingfield 2013, Musvuugwa et al 2015), is sometimes placed as sister to Raffaelea s str. in molecular phylogenies of individual rDNA loci (Musvuugwa et al 2015) and additional coding genes (Dreaden et al 2014). Raffaelea quercivora , which is responsible for Japanese oak wilt and associated with Platypus quercivorus (Kubono & Ito 2002, Kusumoto et al 2014), lies within the R. sulphurea complex in Leptographium s. lat.…”