History
Palms: Importance, Diversity and Distribution
Palms (Arecaceae) are widely distributed worldwide, especially in tropical and subtropical regions. They are more diverse than the other monocotyledonous families (Dransfield et al. 2008). Arecaceae includes about 2,600 species. These species are classified into climbers, shrubs and trees belonging to 181 genera (Nadot et al. 2016).
Map source:
https://www.reddit.com/r/MapPorn/comments/nj93ve/range_of_palm_trees_across_the_world/?utm_source=share&utm_medium=web3x&utm_name=web3xcss&utm_term=1&utm_content=share_button
Arecaceae species are a good food source for frugivores animals lives in the tropics (Bello et al. 2015). Furthermore, in the tropics and subtropics people use palms as raw material for building, food, drink, clothing, fuel, and medicine (Sylvester et al. 2012). In several countries, palm species such as coconut, and oil palm have become main sources of income as well. In addition, these palm species have a significant impact on the forest structure (Muscarella et al. 2020). The most common and well-known Palm species are Adonidia merrillii (Manila palm), Arenga pinnata (Fishtail palm), Calamus sp., Cocos nucifera (coconut), Elaeis guineensis (African oil palm), and Licuala glabra.
Botanically palm species are different from those of broadleaf (dicot) and coniferous (Gymnosperm) trees. Every palm species has its defined morphology and anatomy which determines how the plant grows, functions and reacts to other environmental factors. Systematically, they have large leaves, each having a tubular sheath which splits open at maturity.
Palm species are globally distributed in tropical and sub-tropical climates, and only a few species are in warm-temperate regions (Dransfield et al. 2008). Their species distribution is highly affected by climate, soil chemistry, hydrology and topography and biotic factors, such as vegetation structure and species interactions are also affected. These climatic and environmental factors have made the palm species a unique group of plants thus, the other microorganisms associated with these palm species such as fungi should also have diversity and uniqueness corresponding to the plant species.
Early studies on Palm fungi
“Palm fungi” the name was given since these fungi are unique as the palm species are in the tropics and subtropics. Palm fungi are one of the oldest studied fungal groups. The first noticeable publication dedicated to palm fungi was done by Hyde (1988). Starting from then, more than 100 palm genera have been studied for their associated microfungi (Farr & Rossman 2023). Among these, there are studies on palm fungi from terrestrial, extreme environments, freshwater, and marine habitats. Most studies on palm fungi are on saprobic fungi, in addition to that endophytes and pathogens are also studied in the last few years.
Considering the extreme environmental conditions, remarkable fungi such as Craspedodidymum licualae, C. microsporum, C. siamense, Flammispora bioteca, Jahnula appendiculata, Phruensis brunneispora and Stachybotrys palmae (Pinruan et al. 2004a, b, c) have been reported from peat swamp environments. Peat swamp forests are unique ecosystems that are made by the long-term accumulation of plant material under acidic water-logged conditions. Most of these landscapes are drained to plant oil palm and rubber. Thus, it is obvious that palm species in different environments contain a huge fungal diversity. Hyde (1993) has reported Phomatospora nypae a new species isolated from submerged Nypa petioles and leaf blades in the marine environment in Malaysia. Furthermore, this study has mentioned the fungi associated with Nypa fruticans might be unique as well. Hyde et al. (2000), published 100 palm fungal genera with illustrations. Fröhlich and Hyde (2000) is a collection of microfungi from 20 palm species from Australia, Brunei, Ecuador, and China with a comprehensive review of palm species and their geographical distribution. Taylor and Hyde (2003) contain 288 fungal species belonging to 153 from Australia and China (Hunan, Hubei and Hongkong). In Brazil, from 2009 to June 2010, palm leaf litter was collected and studied and identified 107 species in 79 genera and 25 families. Interestingly most of these species were obtained from leaflets.
Recent studies on palm fungi
During the last few years, studies in palm fungi in Thailand have remarkable improvements. Pinruan et al. (2004a, b) are the first studies use both morphology and DNA sequence data to identify microfungi associated with palms in Thailand. Almost all the studies before these studies used only morphological characteristics. The highest numbers of microfungi have been reported mainly on three palm species in Thailand viz., Eleiodoxa conferta, Licuala longicalycata, and Nypa fruticans (Konta et al. 2022). Konta et al. (2016) introduced a new family, Oxydothidaceae in Xylariales with six new species. In the recent study by Konta et al. (2022), A new genus Triseptatospora and nine new species in Amphisphaeriales, Diaporthales, Distoseptisporales, Glomerellales, Pleosporales, and Xylariales were identified. These results from various regions suggested the high diversity of saprobic palm fungi in Thailand and still, there is a lot to identify.
In addition to the saprobic fungi, few studies have focused on endophytic fungi associated with palm species. Pinruan et al. (2010) reported 20 endophytic basidiomycetes strains which include Fomitopsis cf. meliae, F. cf. ostreiformis, F. cf. pinicola, Perenniporia sp., Pycnoporus sanguineus, Trametes lactinea, and Schizophyllum commune. Endophytes isolated from Oncosperma sp. in Thailand showed efficient plant growth-promoting traits as well as in vitro antagonistic activities (Saengket et al. 2021). This study has reported that Daldinia isolates have promising IAA production, the highest phosphate solubilization, and moderate antagonistic activities. In recent years, several studies have been conducted on fungal pathogens associated with palm species. Kinge et al. (2019) reported Fusarium oxysporum f. sp. elaeidis is one of the most damaging diseases of oil palm in Cameroon. El Meleigi et al. (2019) reported that Phytophthora nicotianae causes bud rot disease in Washingtonian palms in Saudi Arabia. Among all these records on fungi on palm species, Amphisphaeriaceae, Oxydothidaceae, Hypocreaceae, Meliolaceae, Mycosphaerellaceae, Phyllachoraceae, and Xylariaceae species are reported as highly diverse taxa (Fröhlich & Hyde 2000).
Recent Notes
Important NewsUpdated Log
Recent Genus
ThelotremaConiella
Sporoschisma
Recent Species
Hemicorynespora obclavataGuignardia manokwaria
Caudatispora palmicola