Cryphonectriaceae associated with rust-infected Syzygium jambos in Hawaii

Abstract

Syzygium jambos (Myrtales, Myrtaceae) trees in Hawaii are severely affected by a rust disease caused by Austropuccinia psidii (Pucciniales, Sphaerophragmiaceae), but they are commonly co-infected with species of Cryphonectriaceae (Diaporthales). In this study, S. jambos and other trees in the Myrtales were examined on three Hawaiian Islands for the presence of Cryphonectriaceae. Bark samples with fruiting bodies were collected from infected trees and fungi were isolated directly from these structures. Pure cultures were produced and the fungi were identified using DNA sequence data for the internal transcribed spacer (ITS) region, part of the β-tubulin (BT1) gene and the transcription elongation factor-1α (TEF1) gene. Five species in three genera of Cryphonectriaceae were identified from Myrtaceae tree samples. These included Chrysoporthe deuterocubensis, Microthia havanensis and three previously-unknown taxa described here as Celoporthe hauoliensis sp. nov., Cel. hawaiiensis sp. nov. and Cel. paradisiaca sp. nov. Representative isolates of Cel. hauoliensis, Cel. hawaiiensis, Cel. paradisiaca, Chr. deuterocubensis and Mic. havanensis were used in artificial inoculation studies to consider their pathogenicity on S. jambos. Celoporthe hawaiiensis, Cel. paradisiaca and Chr. deuterocubensis produced lesions on young S. jambos trees in inoculation trials, suggesting that, together with A. psidii, they may contribute to the death of trees. Microsatellite markers were subsequently used to consider the diversity of Chr. deuterocubensis on the Islands and thus to gain insights into its possible origin in Hawaii. Isolates of this important Myrtaceae and particularly Eucalyptus pathogen were found to be clonal. This provides evidence that Chr. deuterocubensis was introduced to the Hawaiian Islands as a single introduction, from a currently unknown source.

Micromelanconis kaihuiae gen. et sp. nov., a new diaporthalean fungus from Chinese chestnut branches in southern China

“…1), and differed from the other Melanconis-like genera by its long dumbbell-shaped conidia formed on PDA plates. Hosts are useful taxonomic information in some families of Diaporthales, such as Coryneaceae, Cryphonectriaceae, Erythrogloeaceae and Gnomoniaceae (Voglmayr et al 2012;Jaklitsch and Voglmayr 2019;Roux et al 2020;Wang et al 2020;Yang et al 2020). Hosts are important to separate Melanconis-like genera, Juglanconis inhabit Juglans and Pterocarya of Juglandaceae, Melanconiella and Melanconis occur only on the plant family Betulaceae (Voglmayr et al 2012(Voglmayr et al , 2017(Voglmayr et al , 2019Fan et al 2018b;Jaklitsch and Voglmayr 2020).…”

Myrtaceae in Australia: Use of Cryobiotechnologies for the Conservation of a Significant Plant Family under Threat

“…Threats to Australian flora, including Myrtaceae species, include changing land use, habitat fragmentation, increasing rates of natural disasters-such as extreme fires and flooding-due to climate change, and invasive species [51,52]. Invasive fungal pathogens in particular have been implicated in the decline of a number of species globally, both as individual species and in multi-species interactions [53][54][55][56]. One such species causing concern in Australia and globally is Austropuccinia psidii, a fungal pathogen native to South America that causes a disease known as myrtle rust.…”

Bioactivity of Endophytic Fungi Isolated from Branch of Jambu Mawar (Syzygium jambos (L.) Alston)

“…Therefore, another approach is to isolate the endophytic fungi associated with it. Studies on the isolation of endophytic fungi from specifically the stem bark Roux et al, 2020), from leave and root bark of S. jambos have been previously performed, which have antibacterial activity. Other endophytic fungi can also be found in S. aqueum, such as Aspergillus, Trichoderma, Penicillium, and others, which have antibacterial properties (Habisukan et al, 2021)…”