Host range of meliolaceous fungi in India

V.B. Hosagoudar 1 & G.R. Archana 2

1,2 Tropical Botanic Garden and Research Institute, Palode, Thiruvananthapuram, Kerala 695562, India

Email: 1 vbhosagoudar@rediffmail.com

Date of online publication 26 May 2009

ISSN 0974-7907 (online) | 0974-7893 (print)

Editor: Richard Mibey

Manuscript details:

Ms # o2061

Received 13 September 2008

Final received 07 April 2009

Finally accepted 15 May 2009

Citation:Hosagoudar, V.B. & G.R. Archana (2009). Host range of meliolaceous fungi in India. Journal of Threatened Taxa 1(5): 269-282.

Copyright: © V.B. Hosagoudar & G.R. Archana2009. Creative Commons Attribution 3.0 UnportedLicense. JoTT allows unrestricted use of this article in any medium for non-profit purposes, reproduction and distribution by providing adequate credit to the authors and the source of publication.

Author Details: V.B. Hosagoudar has more than three decades of research experience, has published five books on fungi including Monographs on Meliolales of India and has authored more than 300 research publications.
G.R. Archanais currently working on foliicolous fungi of Western Ghats region of Kerala state under the guidance of Dr. V.B. Hosagoudar. She has 22 research papers in national and international journals.

Author Contribution: The study: GRA with the guidance of VBH for the higher studies on foliicolous fungi. The current paper: Written by both authors.

Acknowledgements:We thank Dr. S. Ganeshan, Director, Tropical Botanic Garden and Research Institute, Palode, Thiruvanan-thapuram, Kerala for the facilities.

Abstract: The order Meliolalescomprises two families, namely, Armatellaceae and Meliolaceae. Except the genera Endomeliolaand Pauhia, India represents rest of the nine genera of this group. The family Armatellaceaeincludes two genera, namely, Armatella and Basavamyces. The family Meliolaceae includes seven genera: Amazonia,Appendiculella, Asteridiella,Ectendomeliola, Irenopsis,Meliola and Prataprajella. All these nine genera represent 613 species and infra-specific taxa known till the year 2006, infected 766 host plants belonging to 349 host genera distributed among 104 families. All the host families and the fungal genera are arranged alphabetically with their corresponding parasite and the host plant. The corresponding number after the host family represents the number of meliolaceous taxa known on the members of that family.

Keywords: Families, hosts, India, Meliolaceae

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Black colony forming parasitic fungi are known as “Black or dark mildews”. These are obligate ecto-parasites producing black colonies on the surface of the host plants. The black colony forming parasitic fungi belong to several taxonomic groups, viz. Hyphomycetes, Meliolales, Schiffnerula and its anamorphic forms, Asterinales, Meliolinaceae, etc. Of these, the fungi belonging to Meliolales can be distinguished by their two celled appressoriate mycelium, setae, presence of globose perithecia with setae, appendages, etc. These are the unique group of fungi which are distinguished very easily. This work gives a clue to the identification of the meliolaceous fungi at a glance based on the hosts and their families. Meliolaceous fungi belong to the order Meliolales and which constitutes two families:

The order Meliolales

Meliolales Gaumann ex Hawksworth& O. Eriksson, Systema Ascomycetum5: 142, 1986.

Parasites on vascular plants. Mycelium mostly superficial, appressoriate. Appressoria mostly two celled, rarely many celled. Phialidesunicellular. Ascomataflattened-globose to globose, ± ostiolate, peridiumsmooth, surface cells protruded, often supplemented with setae, appendages; asci on basal hymenium, unitunicate, 2-8 spored, clavate to cylindrical, persistent or evanescent; ascospores 1-4 septate, brown at maturity.

Type family: Meliolaceae

Discussion

The order Meliolales represents two families to include eleven genera and 2300 species and infra specific taxa. India represents 613 taxawhich forms 26.6% of the world’s meliolaceous fungal flora. The monotypic genera, Pauhia and Endomeliolaare not represented in India. In India, the genus Meliola scores highest number of species and infra specific taxa (453), followed by the genus Asteridiella(73), Irenopsis (31), Amazonia (28),Armatella (13), Appendiculella (10), the genera Basavamyces and Prataprajella (2) and the genus Ectendomeliola is a monotypic genus. Only the recently described genera, Basavamyces and Ectendomeliola are endemic to the Indian continent.

The reported number of flowering plants in India is ca.18000 species (the number varies from 16,500 to 19,395) distributed among ca. 390 families (the number varies from 247-315) (Mudgal & Hajra 1997-99; Sharma et al. 1997; Karthikeyan2000). Of the total known flowering plants, 766 species (42.5%) found infected with these fungi belonging to 349 host genera (of the known 2900 genera, 12%) distributed among 104 families (31%).

Of the total numbers of flowering plant families in India, 104 are infected with meliolaceous fungi, Lauraceaerepresents highest number (49 taxa), Rubiaceae (40 taxa) followed by Fabaceae (39 taxa), Euphorbiaceae (32 taxa), Rutaceae (26 taxa), Apocynaceae (24 taxa), Myrtaceae and Sapindaceae (18 taxa each), Anacardiaceae and Oleaceae (17 taxa each), Meliaceae (16 taxa), Poaceae and Caesalpinaceae (12 taxa each), Verbenaceae and Asclepiadaceae(11 taxa each), Moraceae(10 taxa). Rest of the families represent less than this number. This reveals that the members of these families are more compatible or susceptible to the black mildew fungi than other members.

Of the ten biogeographical regions of India, Trans Himalayan, Desert, Semi Arid and Coastal vegetation (Mangroves) are devoid of these fungi. The Western Ghats and North-East India are very rich in biodiversity. In proportion to 4000 Phanerogams in the Western Ghats, more than 400 meliolas are known. However, from north-east India, only 6 are known. No doubt this region also must be rich in meliolas and the poor representation could be due to inadequate survey and taxonomic study of the group in the area.

These fungi infect variety of plants, viz. exotics, introduced for the aforestation programmes (Hosagoudar et al. 2002; Archana& Hosagoudar 2006), plantation crops (Hosagoudar & Abraham 2000), medicinal plants (Hosagoudar 2003), endemics (Hosagoudar2003), economically important plants, plants of non-wood forest produce, wild edible plants, commercially timber yielding plants (Hosagoudar2006 a,b,c, etc.). The study of the occurrence of these fungi on the sacred groves has also been conducted as a case of reference (Hosagoudar et al. 2005).

These fungi infect both wild and cultivated plants but more on wild. However, the infection is also noticed on wild relatives of present day’s cultivars viz. Vignaspp., Mangifera andamanica, etc. These fungi are host specific but still there is a both specific and generic host range.

Most of the fungi are restricted in their distribution to their biogeographicalregions. However, Asteridiella malloti(Hansf. & Thirum.) Hansf., Meliola bauhiniicola Yamam, M. chandleri Hansf., M. heudelotii Gaill., M. maredumilliana Hosag. & Mohanan, M. mayapeae Stev. and, M. opiliae Sydow are known from the Western Ghats and Eastern Ghats (Deccan Plateau) in the peninsular India; Meliola butleri Sydow, M. malacotricha Speg., M. mitragynae Sydow and M. tabernaemontanicola Hansf. & Thirum. are known from Western Ghats and Himalayan region, Meliola simillima Ellis & Everh.var. major Hansf. and M. tawaoensis Hansf. are common to Eastern Ghats and Himalayan region; Meliola mangiferaeEarle is common to Western Ghats and Andaman Islands. This indicates that although endemism is very prevalent among these, there are, however some with wide geographical distribution.

These fungi are predominantly on forest plants but are not uncommon on plantation crops like Mango, Cinnamomum, Cashew, Wattles, etc. (Hosagoudar & Balakrishnan1995; Hosagoudar & Abraham 2000).

A maiden venture on certain pockets of the forest plants yielded several novelties. Hence, the nature convinces us that we are in the beginning stage in understanding of the microbes.

References

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Hosagoudar, V.B., T.K. Abraham & S. Shiburaj (2002). Black mildew disease on Acacia species in India. Journal of Mycopathol.Res. 40: 45-47.

Archana, G.R. & V.B. Hosagoudar(2006). Black mildew disease on wattles (Acaciaspp.) in Kerala state. National Conference on Recent Trends in Mycological Research, Dec. 28th & 29, J.J College of Arts and Sci. Pudukottai,TN, p. 85.

Hosagoudar, V.B. (2003). Meliolaceous fungi on rare medicinal plants in southern India. Zoos’ Print Journal 18: 1147-1154.

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