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 firstname.lastname@example.org
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 Ascomycetum 5: 142, 1986.
Parasites on vascular plants. Mycelium mostly superficial, appressoriate. Appressoria mostly two celled, rarely many celled. Phialides unicellular. Ascomata flattened-globose to globose, ± ostiolate, peridium smooth, 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
The order Meliolales represents two families to include eleven genera and 2300 species and infra specific taxa. India represents 613 taxa which forms 26.6% of the world’s meliolaceous fungal flora. The monotypic genera, Pauhia and Endomeliola are 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; Karthikeyan 2000). 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, Lauraceae represents 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 (Hosagoudar 2003), economically important plants, plants of non-wood forest produce, wild edible plants, commercially timber yielding plants (Hosagoudar 2006 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. Vigna spp., 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 biogeographical regions. 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 mangiferae Earle 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 & Balakrishnan 1995; 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.
Hosagoudar, V.B. & T.K. Abraham (2000). Black mildews (Meliolaceae) on Plantation crops. Journal of Mycopatholgical Research 38: 1-6.
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 (Acacia spp.) 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.
Hosagoudar, V.B. (2003). Endemic Meliolas and Meliolas on Endemic plants in Western Ghats, India. Zoos’ Print Journal 18: 1243-1252.
Hosagoudar, V.B. & H. Biju (2003). Host range of Meliola jasmini Hansf. & Stev. New Botanist 30: 153-162.
Hosagoudar, V.B., H. Biju & K.A.Anu Appaiah (2005). Foliar fungal parasites of Western Ghats found on the plants of sacred groves in Dakshina Kannada and Udupi districts of Karnataka State. Journal of Mycopathological Research 43: 203-209.
Hosagoudar, V.B. (2006). Meliolaceous fungi on economically important plants in India-II: on plants of non-wood forest produce. Zoos’ Print Journal 21: 2356-2371.
Hosagoudar, V.B. (2006). Meliolaceous fungi on economically important plants in India-III: on wild edible plants. Zoos’ Print Journal. 21:2425-2438.
Hosagoudar, V.B. (2006). meliolaceous fungi on an economically important plants in India-I. on commercially timber yielding plants. Journal of Economic & Taxonomic Botany 30: 818-850.
Hosagoudar, V.B. (2006). Biogeographical distribution of Meliolaceae members in India. Zoos’ Print Journal 21: 2495-2505.
Hosagoudar, V.B., H. Biju & K.A. Anu Appaiah (2006). Studies on foliicolous fungi – XX. Microfungi of Coorg, Karnataka. Journal of Mycopathological Research 44: 1-25.
Hosagoudar, V.B. & H. Biju (2006). Studies on foliicolous fungi – XXII. Microfungi of Silent Valley National Park, Palghat district in Kerala State. Journal of Mycopathological Research 44: 39-48.
Karthikeyan, S. (2000). Statistical analyses of flowering plants of India. In: Singh, N.P., Singh, D.K., Hajra, P.K. and Sharma, B.D. (eds.). Flora of India. Introductiory vol. II. 201-217. New Delhi.
Mudgal, V. & P.K. Hajra (1997-99). Floristic diversity and conservation strategies in India. Botanical Survey of India, Dehra Dun, Vol. I&II.
Sharma, J.R., V. Mudgal & P.K. Hajra (1997). Floristic diversity and conservation strategies in India. Cryptogams and Gymnosperms I. Botanical Survey of India, Dehra Dun.