Identification and characterization of Neopestalotiopsis fungi associated with a novel leaf fall disease of rubber trees (Hevea brasiliensis) in Thailand

Research Highlights: Pestalotiopsis pini sp. nov. is an emerging pathogen on stone pine, Pinus pinea L., in Portugal. Background and Objectives: Stone pine is one of the most important forest tree species in Portugal and in the whole Mediterranean basin. Pestalotiopsis species are common endophytes, saprobes or pathogens in a variety of hosts and environments. The objective of the present study was to identify the Pestalotiopsis species associated with the symptomatic stone pine trees. Materials and Methods: Samples of stone pine trees showing shoot blight and stem necrosis were obtained from stone pine orchards and urban areas in Portugal, and the isolated Pestalotiopsis species were identified based on morphology and combined ITS, TEF and TUB DNA sequence data. Artificial inoculations on one-year-old stone pine seedlings were performed with the two species most frequently found in association with shoot blight disease. Results: Five Pestalotiopsis spp. were isolated. A taxonomic novelty, Pestalotiopsis pini is described, representing a new pathogen for stone pine. Conclusions: Pestalotiopsis species may represent a threat to the health of pine forests in the Mediterranean basin. Future research should be done in order to increase our knowledge about the potential impact of pestalotioid species in stone pine, in order to develop management strategies against these pathogens.

https://www.mdpi.com/1999-4907/11/8/805/pdf

Pestalotiopsis pini sp. nov., an Emerging Pathogen on Stone Pine (Pinus pinea L.)

Mango is one of the most popular and nutritious fruits in the world and Mexico is the world’s largest exporter. There are many diseases that directly affect fruit yield and quality. During the period 2016–2017, leaves with grey leaf spots were collected from 28 commercial mango orchards distributed in two main production areas in Sinaloa State of Mexico, and 50 Neopestalotiopsis isolates were obtained. Fungal identification of 20 representative isolates was performed using morphological characterization and phylogenetic analysis based on the internal transcribed spacer (ITS) region of ribosomal DNA, part of the translation elongation factor 1-alpha (TEF) and the β-tubulin (TUB) genes. Phylogenetic analysis indicated that the 20 isolates from this study formed four consistent groups, however, overall tree topologies do not consistently provide a stable and sufficient resolution. Therefore, even though morphological and phylogenetic separation is evident, these isolates were not assigned to any new taxa and were tentatively placed into four clades (clades A–D). Pathogenicity tests on detached mango leaves of cv. Kent showed that the 20 isolates that belong to the four Neopestalotiopsis clades from this study and induce lesions on mango leaves. This is the first report of species of Neopestalotiopsis causing mango grey leaf spot disease in Mexico.

https://www.mdpi.com/2076-0817/9/10/788/pdf

Characterization of Neopestalotiopsis Species Associated with Mango Grey Leaf Spot Disease in Sinaloa, Mexico.

Morphological and molecular identification of Neopestalotiopsis clavispora causing flower blight on Anthurium andraeanum in Thailand

https://link.springer.com/content/pdf/10.1007/s10658-021-02433-2.pdf

Neopestalotiopsis clavispora and Pseudopestalotiopsis camelliae-sinensis causing grey blight disease of tea (Camellia sinensis) in Malaysia

Brazil is the leader in the global ranking of forest productivity; however, one of the major challenges to eucalyptus production is the existence of fungal diseases. A severe epidemic caused by pestalotiopsis‐like fungi was observed in a forest nursery in Brazil, causing a huge impact on the eucalyptus micropropagation stages. The aims of the present study were to identify the causal agents associated with pestalotiopsis leaf spot and dieback in eucalyptus, assess their pathogenicity to different commercial clones, and evaluate which conditions favour conidial germination and infection by the pathogens. Multilocus phylogenetic analyses using ITS, TEF and TUB identified the isolates as members of Neopestalotiopsis and segregated them into three species. Isolates from all Neopestalotiopsis spp. caused symptoms on unwounded eucalyptus leaves and disease development was strongly dependent on long leaf wetness periods (≥72 h). All four commercial clones tested were susceptible to the pathogen. These results clearly dispute the commonly held assumption that pestalotioid fungi are weak and opportunistic pathogens. This is the first report of different phylogenetic species of Neopestalotiopsis causing dieback, leaf and stem lesions in eucalyptus cuttings and provides a basis for developing novel disease management strategies in forest nurseries.

S. S. Salcedo

Papers

Infection by Neopestalotiopsis spp. occurs on unwounded eucalyptus leaves and is favoured by long periods of leaf wetness