Dr Ariska van der Nest

Postdoctoral Fellow

About

I joined the RGE-FABI Tree Health Programme in January 2022 as a Postdoctoral Fellow. My research will focus on Ganoderma root rot in Indonesian plantations.

I completed my PhD in 2021 as part of the Tree Protection Co-operative Programme (TPCP). Dothistroma needle blight (DNB), caused by Dothistroma piniand D. septosporum, and Brown spot needle blight (BSNB), caused by Lecanosticta species, are two needle diseases of Pinus species that have become diseases of emerging importance in the northern Hemisphere in the past twenty years. My PhD project focused on the diversity and invasion biology of these two important pine needle pathogen genera.

As a part of my PhD, I identified six species of Lecanosticta, of which four are novel taxa, from a large collection of Lecanosticta isolates from infected pine needles from Guatemala, Honduras and Nicaragua based on sequence comparisons of five gene regions. The well-known pathogen, L. acicola was not present in any of the samples investigated in my studies, indicating that this might be a Northern Hemisphere pathogen. It was concluded that due to the high species diversity of Lecanosticta in Mesoamerica, that this region is considered a centre of diversity for the genus.

Dothistroma needle blight is caused by two morphologically indistinguishable species, Dothistroma pini and D. septosporum. Dothistroma septosporum has a worldwide occurrence while D. pini has only been recorded in the Northern hemisphere. I also investigated the population diversity, structure and mode of reproduction and likely means of spread for a large collection of D. pini obtained from 12 countries in Europe over a 12-year period. The observed population structure as well as several shared multilocus haplotypes between non-bordering countries provides evidence that the occurrence and spread of D. pini on the continent has been strongly influenced by human mediated activities in Europe.

The final part of the study addressed the unprecedented DNB outbreaks observed in Cantabria in Spain, in 2015, by determining the causal agent, and determined the population structure, genetic diversity and mode of reproduction of the pathogen involved, from three infected sites of planted subspecies. was confirmed as the causal agent and the high genetic diversity observed in isolates obtained from Cantabria suggested that the pathogen was not recently introduced into the region.

Highlights

Presentations and Posters

van der Nest, A.,Wingfield, M.J., Sadiković, D., Mullett, M., Queloz, V., Adamčíková, K., Davydenko K., Barnes, I. 2020. Population structure and diversity of Dothistroma pini in Europe suggests human mediated movement of the needle blight pathogen. MSA 2020 'Mycology from the Clouds' virtual meeting. Graphical abstract.

van der Nest, A., Wingfield, M.J., Barnes, I. 2018. The rising threat of novel pine needle pathogens from Central America under expanding global cultivation. 44th Conference of the South African Association of Botanists, 9-12 January 2018, Pretoria, South Africa. p91.

Barnes, I., van der Nest, A., Ortiz, P., Wingfield, M. 2017. New cryptic species and a putative center of diversity for the pine pathogens Dothistromaand Lecanosticta. IUFRO 125th Anniversary Congress, 18-22 September 2017, Freiburg, Germany. p221.

van der Nest, A.,Wingfield, M.J., Barnes, I. 2017. Diversity of Lecanostictaspecies in Central America suggests a centre of diversity for an important group of pine needle pathogens. 50th Anniversary Congress of the Southern African Society for Plant Pathology, 15-18 January 2017, Champagne Sports Resort, Drakensberg. Poster 26.

van der Nest, A., Wingfield, M.J., Barnes, I. 2016. The phylogenetic diversity of Lecanostictain Central America suggests a centre of diversity for this genus. 4th Joint congress of the SA Society for Bioinformatics and the SA Genetics Society, 20-23 September 2016, Durban, South Africa. p35

van der Nest, A., E.T. Steenkamp & G.J. Marais. 2009. Phylogenetic relatedness of Phoma sorghina as a mycotoxigenic fungus in South Africa. International Society for Mycotoxicology conference, 9-11 September 2009, Tullin, Austria.

van der Nest, A., Steenkamp, E.T., Marais, G.J. 2009. Phylogenetic definition of Phoma sorghina based on the ITS, EF-1α and β-tubulin gene regions. 46th Congress of the Southern African Society for Plant Pathology and 6th Congress of the African Mycological Association (AMA), 25 – 28 January 2009, Villa Via Hotel, Gordon’s Bay, South Africa. p110.

van der Nest, A., Steenkamp, E.T., Marais, G.J. 2008. Phylogenetic diversity of Phoma sorghina in Southern Africa. Biennial Conference of the South African Society for Microbiology (Bio-08), Rhodes University, 21-25 January 2008. p 40.

My Publications

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Aylward J, Wilson AM, Visagie CM, Spraker J, Barnes I, Buitendag C, Ceriani C, Del Mar Angel L, du Plessis D, Fuchs T, Gasser, K, Krämer D, Li W, Munsamy K, Piso A, Price J-L, Sonnekus B, Thomas C, van der Nest A, van Dijk A, van Heerden A, van Vuuren N, Yilmaz N, Duong TA, van der Merwe NA, Wingfield MJ, Wingfield BD. (2024) IMA Genome – F19: A genome assembly and annotation guide to empower mycologists, including annotated draft genome sequences of Ceratocystis pirilliformis, Diaporthe australafricana, Fusarium ophioides, Paecilomyces lecythidis, and Sporothrix stenoceras. IMA Fungus 10.1186/s43008-024-00142-z

Mesanza N, Barnes I, van der Nest A, Raposo R, Berbegal M, Iturritxa E. (2023) Genetic diversity of Lecanosticta acicola in Pinus ecosystems in Northern Spain. Journal of Fungi 10.3390/jof9060651

van der Nest A, Wingfield MJ, Sadiković D, Mullett MS, Marçais B, Queloz V, Adamčíková K, Davydenko K, Barnes I. (2023) Population structure and diversity of the needle pathogen Dothistroma pini suggests human-mediated movement in Europe. Frontiers in Genetics 10.3389/fgene.2023.1103331

Adamčíková K, Jánošíková Z, van der Nest A, Adamčík S, Ondrušková E, Barnes I. (2021) Population structure and genetic diversity suggest recent introductions of Dothistroma pini in Slovakia. Plant Pathology 10.1111/ppa.13428

Aglietti C, Meinecke CD, Ghelardini L, Barnes I, van der Nest A, Villari C. (2021) Rapid detection of pine pathogens Lecanosticta acicola, Dothistroma pini and D. septosporum on needles by probe-based LAMP assays. Forests 10.3390/f12040479

Mesanza N, Raposo R, Elvira‐Recuenco M, Barnes I, van der Nest A, Hernández M, Pascual MT, Barrena I, Martín US, Cantero A, Hernandez‐Escribano L, Iturritxa E. (2021) New hosts for Lecanosticta acicola and Dothistroma septosporum in newly established arboreta in Spain. Forest Pathology 10.1111/efp.12650

van der Nest A, Wingfield MJ, Janoušek J, Barnes I. (2019) Lecanosticta acicola: A growing threat to expanding global pine forests and plantations. Molecular Plant Pathology 10.1111/mpp.12853

van der Nest A, Wingfield MJ, Ortiz PC, Barnes I. (2019) Biodiversity of Lecanosticta pine-needle blight pathogens suggests a Mesoamerican Centre of origin. IMA Fungus 10.1186/s43008-019-0004-8

Bradshaw RE, Sim AD, Chettri P, Dupont P-Y, Guo Y, Hunziker L, McDougal RL, van der Nest A, Fourie A, Wheeler D, Cox MP, Barnes I. (2019) Global population genomics of the forest pathogen Dothistroma septosporum reveal chromosome duplications in high dothistromin-producing strains. Molecular Plant Pathology 10.1111/mpp.12791

Barnes I, van der Nest A, Mullett MS, Crous PW, Drenkhan R, Musolin DL, Wingfield MJ. (2016) Neotypification of Dothistroma septosporum and epitypification of D. pini, causal agents of Dothistroma needle blight of pine. Forest Pathology 10.1111/efp.12304