The advent of next-generation sequencing (NGS) technologies has revolutionised research capacity and its broad applicability over the past decade. These technologies have directly impacted researchers’ ability to understand host-pathogen interactions, holistically, and on a molecular scale. Recently, the avocado industry has begun to unravel some of the underlying mysteries that pertain to prevalent avocado pests and diseases; the Avocado Research Programme (ARP) has been highly influential in this space.

As a founding member of the Avocado Genome Consortium - an international collaborative effort which was established in 2016 - the ARP has directly contributed to the development of a high quality, chromosome-level reference genome assembly for Persea americana (avocado). The Avocado Genome Consortium has used this new reference genome to re-sequence more than 10 additional cultivars and rootstocks as part of an ongoing project, with plans to increase this number soon. Provided with this data, researchers will be able to accelerate the arduous process of selecting rootstocks and cultivars with desirable traits.

As part of the broader objectives of the Avocado Genome Consortium, transcriptomic data has also been generated. This data will be utilized to answer fundamental questions pertaining to the evolutionary biology, gene expression, physiological processes, and molecular pathways in avocado. Transcriptomic data from a dual RNA-sequencing experiment - involving both susceptible and partially resistant avocado rootstocks challenged with Phytophthora cinnamomi - was also used to identify avocado defence targets and discovery of pathogen effectors involved in disease development. The data from this work has been published across several research articles and will be used to further our understanding of the avocado-P. cinnamomi interaction.

 

The researchers involved are:

  • David Kuhn, USDA, Florida
  • Patricia Manosalva, UCR, California
  • Noëlani van den Berg, UP, South Africa
  • Antonio Javier Matas Arroyo, Departamento de Biología Vegetal, University of Malaga, Spain
  • Aureliano Bombarley Gomez, Virginia Tech Horticulture, USA
  • Randy Ploetz, University of Florida, USA
  • Alan Chambers, University of Florida, USA

 

New Publications

Magagula P, Swart V, Fourie A, Vermeulen A, Nelson JH, van Rooyen Z, van den Berg N. (2025) Avocado rhizosphere community profiling: white root rot and its impact on microbial composition. Frontiers in Microbiology 16 10.3389/fmicb.2025.1583797
van den Berg N, Magagula P, Backer R, Swart V. (2025) Towards developing an integrated approach for the treatment of white root rot in commercial avocado orchards. Phytoparasitica 53(32) 10.1007/s12600-025-01250-1 PDF
Harvey A, van den Berg N, Swart V. (2025) In silico characterisation of the avocado WAK/WAKL gene family with a focus on genes involved in defence against Phytophthora cinnamomi. Frontiers in Plant Science 15:1474781. 10.3389/fpls.2024.1474781 PDF
Harvey A, van den Berg N, Swart V. (2024) Describing and characterizing the WAK/WAKL gene family across plant species: a systematic review. Frontiers in Plant Science 15:1467148. 10.3389/fpls.2024.1467148 PDF
Joubert M, van den Berg N, Theron J, Swart V. (2024) Global transcriptomic analysis in avocado nursery trees reveals differential gene expression during asymptomatic infection by avocado sunblotch viroid (ASBVd). Virus Research 339:199263. 10.1016/j.virusres.2023.199263. PDF
Anbu SP, Swart V, van den Berg N. (2023) Unmasking the invaders: NLR-mal function in plant defense. Frontiers in Plant Science 14:1307294. 10.3389/fpls.2023.1307294 PDF
Backer R, Naidoo S, van den Berg N. (2023) The expression of the NPR1-dependent defense response pathway genes in Persea americana (Mill.) following infection with Phytophthora cinnamomi. BMC Plant Biology 23(1):548. 10.1186/s12870-023-04541-z PDF
Wingfield BD, Berger DK, Coetzee MPA, Duong TA, Martin A, Pham NQ, Van den Berg N, Wilken PM, Arun-Chinnappa KS, Barnes I, Buthelezi S, Dahanayaka BA, Durán A, Engelbrecht J, Feurtey A, Fourie A, Fourie G, Hartley J, Kabwe ENK, Maphosa M, Narh Mensah DL, Nsibo DL, Potgieter L, Poudel B, Stukenbrock EH, Thomas C, Vaghefi N, Welgemoed T, Wingfield MJ. (2022) IMA genome‑F17 Draft genome sequences of an Armillaria species from Zimbabwe, Ceratocystis colombiana, Elsinoë necatrix, Rosellinia necatrix, two genomes of Sclerotinia minor, short‑read genome assemblies and annotations of four Pyrenophora teres isolates from barley grass, and a long-read genome assembly of Cercospora zeina. 13:19. 10.1186/s43008-022-00104-3
Wienk R, Mostert‑O’Neill M, Abeysekara N, Manosalva P, Freeman B, van den Berg N. (2022) Genetic diversity, population structure and clonal verification in South African avocado cultivars using single nucleotide polymorphism (SNP) markers. Tree Genetics and Genomes 18(41) 10.1007/s11295-022-01573-8 PDF
Joubert M, van den Berg N, Theron J, Swart V. (2022) Transcriptomics Advancement in the Complex Response of Plants to Viroid Infection. International Journal of Molecular Sciences 23(7677) 10.3390/ijms23147677 PDF
Backer R, Engelbrecht J, van den Berg N. (2022) Differing Responses to Phytophthora cinnamomi Infection in Susceptible and Partially Resistant Persea americana (Mill.) Rootstocks: A Case for the Role of Receptor-Like Kinases and Apoplastic Proteases. Frontiers in Plant Science 13 10.3389/fpls.2022.928176 PDF
Hartley J, Engelbrecht J, Van den Berg N. (2022) Detection and prevalence of Rosellinia necatrix in South African avocado orchards. European Journal of Plant Pathology 10.1007/s10658-022-02532-8
Fick A, Swart V, Van den Berg N. (2022) The ups and downs of plant NLR expression during pathogen infection. Frontiers in Plant Science 13:921148. 10.3389/fpls.2022.921148
Midgley KA, van den Berg N, Swart V. (2022) Unraveling plant cell death during Phytophthora Infection. Microorganisms 10(6) 10.3390/microorganisms10061139 PDF
Miyambo TM, Backer R, Engelbrecht J, Joubert F, van der Merwe NA, van den Berg N. (2022) The Identification and Characterization of Endopolygalacturonases in a South African Isolate of Phytophthora cinnamomi. Microorganisms 10(1061) 10.3390/microorganisms10051061 PDF
Fick A, Swart V, Backer R, Bombarely A, Engelbrecht J, van den Berg N. (2022) Partially Resistant Avocado Rootstock Dusa® Shows Prolonged Upregulation of Nucleotide Binding-Leucine Rich Repeat Genes in Response to Phytophthora cinnamomi Infection. Frontiers in Plant Science 13:793644. 10.3389/fpls.2022.793644
Engelbrecht J, Duong TA, Paap T, Hulbert JM, Hanneman J, Van den Berg N. (2022) Population genetic analyses of Phytophthora cinnamomi reveals three lineages and movement between natural vegetation and avocado orchards in South Africa. 10.1094/PHYTO-10-21-0414-R
Magagula P, Taylor N, Swart V, Van den Berg N. (2021) Efficacy of Potential Control Agents Against Rosellinia necatrix and Their Physiological Impact on Avocado. Plant Disease 105(11):PDIS-08. 10.1094/PDIS-08-20-1751-RE
Joubert M, Backer R, Engelbrecht J, Van den Berg N. (2021) Expression of several Phytophthora cinnamomi putative RxLRs provides evidence for virulence roles in avocado. PLoS ONE 16(7):e0254645. 10.1371/journal.pone.0254645 PDF
Engelbrecht J, Duong TA, Prabhu AS, Seedat M, van den Berg N. (2021) Genome of the destructive oomycete Phytophthora cinnamomi provides insights into its pathogenicity and adaptive potential. BMC Genomics 22:302. 10.1186/s12864-021-07552-y
Van den Berg N, Swart V, Backer R, Fick A, Wienk R, Engelbrecht J, Prabhu S. (2021) Advances in understanding defense mechanisms in Persea americana against Phytophthora cinnamomi. Frontiers in Plant Science 12:123. 10.3389/fpls.2021.636339
Mufamadi Z, Fourie G, Willis-Boyum A, van den Berg N. (2020) Husk rot disease: causal agents and disease epidemiology. SAMAC Journal PDF
Malefo M, Mathibela O, Makgopa E, Crampton BG. (2020) Investigating the role of Bowman-Birk serine protease inhibitor in Arabidopsis plants under drought stress. Plant Physiology and Biochemistry 149:286-293. 10.1016/J.PLAPHY.2020.02.007
Welgemoed T, Pierneef R, Sterck L, Van de Peer Y, Swart V, Scheepers KD, Berger DK. (2020) De novo assembly of transcriptomes from a B73 maize line introgressed with a QTL for resistance to gray leaf spot disease reveals a candidate allele of a lectin receptor-like kinase. Frontiers in Plant Science http://bit.ly/2SmKPmT
Van den Berg N, Du Toit M, Morgan SW, Fourie G, De Beer ZW. (2019) First Report of Fusarium euwallaceae on Persea americana in South Africa. Plant Disease 10.1094/PDIS-10-18-1818-PDN
Zumaquero A, Martinez-Ferri E, Matas AJ, Reeksting B, Olivier NA, Pliego-Alfaro F, Barcelo A, van den Berg N, Pliego C. (2019) Rosellinia necatrix infection induces differential gene expression between tolerant and susceptible avocado rootstocks. PLoS ONE 14(2):e0212359. 10.1371/journal.pone.0212359
Backer R, Naidoo S, van den Berg N. (2019) The NONEXPRESSOR OF PATHOGENESIS-RELATED GENES 1 (NPR1) and Related Family: Mechanistic Insights in Plant Disease Resistance. Frontiers in Plant Science 10:102. 10.3389/fpls.2019.00102
Nsibo DL, Barnes I, Kunene NT, Berger DK. (2019) Influence of farming practices on the population genetics of the maize pathogen Cercospora zeina in South Africa. Fungal Genetics and Biology 125:36-44. 10.1016/j.fgb.2019.01.005
Kuhn DN, Livingstone DS, Richards JH, Manosalva P, van den Berg N, Chambers AH. (2019) Application of genomic tools to avocado (Persea americana) breeding: SNP discovery for genotyping and germplasm characterization. Scientia Horticulturae 246:1-11. 10.1016/j.scienta.2018.10.011
van den Berg N, Mohamed W, Olivier NA, Swart V, Crampton B. (2018) Transcriptome analysis of an incompatible Persea americana-Phytophthora cinnamomi interaction reveals the involvement of SA- and JA-pathways in a successful defense response. PLoS ONE 13(10):e0205705. 10.1371/journal.pone.0205705