Editorial: Emerging Fungal Plant Pathogens

1 Center for Mountain Futures, Kunming Institute of Botany, Chinese Academy of Science, Kunming, China, 2 School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China, 3 Department of Plant Pathology and Microbiology, College of Bioresources and Agriculture, National Taiwan University, Taipei, Taiwan, 4 CSIR-National Institute of Oceanography Regional Centre, Visakhapatnam, India, 5 Department of Health Sciences, Faculty of Medicine and Health Sciences, University of Mauritius, Reduit, Mauritius

oilseed rape, vegetables, condiment, and forage brassicas. This review discusses the factors affecting the emergence of the disease and efficient disease control measures. Previously, a lack of information on critical aspects of this pathogen's life cycle limited the development of effective control measures. Gunasinghe et al. confirmed the ability of N. capsellae to switch between two morphologies (septate hyphae and singlecelled yeast phase) on a range of artificial culture media (in-vitro) or in planta on the host surface before infection occurs. It was shown that the hyphae-to-yeast transformation occurs through the production of two morphologically distinguishable blastospore (blastoconidia) types (meso-blastospores and micro-blastospores) and arthrospores (arthroconidia).
Bipolaris sorokiniana (syn: Cochliobolus sativus) is the causal agent of a wide range of cereal diseases. Al-Sadi summarized the latest findings on B. sorokiniana, with specific emphasis on genetic, chemical, cultural, and biological control measures. Hazelnut (Corylus heterophylla), an important nut crop in China, is reportedly in decline due to the destructive effects of fungal branch canker and dieback. To document the main fungal pathogens from Chinese wild hazelnut, Gao et al. isolated 51 fungi. Three Cytospora and two Diaporthe species were identified based on morphological observations coupled with multi-locus phylogenetic analyses, and they also provided additional data on three new species, viz. C. corylina, C. curvispora, and D. corylicola while two known species, C. leucostoma and D. eres are also documented herein.
Thambugala et al. discussed how fungal antagonists play an important role in controlling plant pathogens and diseases. Since modern agricultural practices are shifting towards reducing the usage of chemically synthesized pesticides, various biocontrol methods, strategies and approaches are being used in plant disease management, and fungi are highlighted as one of the successful methods. Powdery mildew caused by Erysiphe cichoracearum seriously affects the yield and quality of tobacco leaves, and once it occurs, it often results in substantial economic losses. Jiao et al. investigated the biocontrol efficiency of Bacillus amyloliquefaciens YN201732 against E. cichoracearum. The results from in vitro, spore germination, and greenhouse-pot studies demonstrated that antimicrobial lipopeptides, especially bacillomycin D and fengycin, may contribute to the prevention and control of tobacco powdery mildew. A new fungal species, Penicillium linzhiense is isolated and described in Liang et al. with the potential for usage as a biocontrol agent, especially for economically important phytopathogens or emerging pathogens causing diseases on citrus or rice. Recent advancements in the improvement and application of molecular methods for diagnosing widespread and emergent plant pathogenic fungi are discussed in Hariharan and Prasannath. Grasslands are an ecologically and economically important component of the earth's vegetation, and fungal communities in grasslands play a huge role on the stability of grasslands. Karunarathna et al. addressed the taxonomy, phylogeny and ecology of grassland fungal pathogens and their interactions in grassland ecosystems. This review highlights the importance of understanding the behavior of fungal pathogens in highly diverse grasslands, providing novel insights for controlling diseases in commercial crop fields.
Climate change seriously impacts agricultural practices and food security. It has the potential to negatively affect numerous economically important crops in the future. In addition, perennial crops, such as tea, are particularly vulnerable. Climate change will not only affect crops but also likely affect crop-associated fungal pathogens. Tibpromma et al. predicted how future climatic conditions will impact tea and its associated pathogens.
In summary, this Research Topic with 10 scientific contributions consolidates and expands our knowledge regarding recent advances in plant fungal pathogens and their control measures. To facilitate the effective management of diseases, it is vital to accurately and rapidly detect and identify plant pathogenic fungi, especially ones emerging on economically important crops. In this context, the research articles published herein provide taxonomic information on fungal species supplemented with DNA sequence data to assist future plant pathologists and mycologists better identify similar species.

AUTHOR CONTRIBUTIONS
SK, SM and RJ drafted the editorial, and all authors contributed to editorial revision. All authors contributed to the article and approved the submitted version.