Fungal Diversity in phylloplane of castor plant (Ricinus communis L): the primary food plant of Eri Silkworm

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1 Scholarly Journal of Agricultural Science Vol. 4(2), pp February, 2014 Available online at ISSN Scholarly-Journals Full Length Research Paper Fungal Diversity in phylloplane of castor plant (Ricinus communis L): the primary food plant of Eri Silkworm A. Borgohain 1 *, R. Das and M. Chutia 2 1 Central Muga Eri Research and Training Institute 2 Central Silk Board, Lahdoigarh, Jorhat , Assam Accepted 27 January, 2014 Castor plant (Ricinus communis L) is a non-edible oilseed crop with unique oil features for the chemical industry as well as an important source of income for the people of North East India. It is a primary food plant of eri silkworm (Samia ricini Donovan). Fungal diversity of R. communis L was studied during two seasons i.e. summer (March-June) and winter (November-February) season along with the meteorological parameters. A total of 11 fungi were isolated during the seasons. The present investigation showed that 5 species of fungi viz. Alternaria ricini, Aspergillus fumigatus, Cercospora ricinela, Curvularia clavata, Fusarium sp. were dominant during the summer and 3 fungal species viz. Emericella nidulans, Leveillula taurica, Melampsora ricini were restricted to the winter season only. The rest of the species were common in both the season. Maximum numbers of fungi were isolated during the month of March and April and minimum numbers of fungi were isolated during the month of December-January. A. alternata and C. ricinela were found to be most abundant species during all the seasons. These fungal species have some potential role for growth and development of the plant. Key words: Fungal diversity, Ricinus communis L,Season. INTRODUCTION Castor (Ricinus communis L) belongs to the Euphorbiaceae is a semi-tropical perennial grown extensively in warm temperature and tropical regions of the world (Phillips and Martyn, 1999). Castor plants can be basically divided into two types, tall (giant) and short (dwarf). The caster plant is a robust annual plant that grows between 2-5 meters in one season with a temperature of about 23 C and relative humidity of about 50%. Castor is a drought resistant crop prefers mm rainfall during growing season of days. It does not tolerate heavy rainfall or water logging. It prefers deep sandy loam soil (ph 6) (Popova, 1963, Weiss, 1983). Under dry conditions, yields are about t/ha but reaches t/ha under irrigation. Castor oil is regarded as one of the best laxative and purgative preparations available. It is of particular benefit for children and pregnant women due to its mild action in easing constipation, colic and diarrhoea due to slow *Corresponding author. aborgohain0@gmail.com. digestion. Castor oil is used for a range of industrial purposes from soap making to vanishes. Castor oil is used very effectively in the treatment of rheumatic and skin disorders (Zahir et al., 2010). The surface of leaves contain stimulatory or inhibitory substances that regulate the colonization of leaf surface organisms (Fating and Khare, 1978). Again, leaf infected with a pathogen modifies the surface microflora which protects the leaf against subsequent infection. The phylloplane microflora is subjected to the influence of various environmental factors and physiological changes in the plants and that too due to onset of diseases (Sinha, 1965). Phylloplane microflora of rice, cotton and cirtus has antagonistic and preinoculative protective ability toward pathogenic microorganisms (Anuratha and Gnanamanickam, 1987; Saikia and Chowdhury, 1993; Santhi et al, 1997) The knowledge of phylloplane micro-organisms has been important for management of foliar diseases in view of the adverse effect of fungicides on environment and run down of host resistance over a period of time. Indigenous fungal as well as bacterial populations are

2 Scholarly J. Agric. Sci. 82 Figure1. Full grown castor plant in the field found efficient to suppress the diseases by reducing pathogen population and thereby minimizing the disease severity. Many microorganisms are capable of influencing the growth of the pathogens (Maji, 2003). In the present study quantification of the phylloplane microorganisms of castor was attempted during summer and winter season. Mycoflora of castor varies in size and diversity depending on the influence of numerous biotic and abiotic factors which affect their growth and survival. These factors also include temperature and humidity (Dix and Webster, 1995). The major groups of leaf surface mycoflora are present at any time of the year, but there are also evidences for seasonal succession (Blakeman, 1993). The succession of mycoflora on leaf surface presents an interesting model for studying functional relationships between plants and mycoflora (Alamiri, 2008). The current investigation is one of the series of studies concerning the ecological relationships and interactions of fungi in the phylloplane of R. communis. The aim of this research is to determine the main constituents of the mycoflora on the leaves of R. communis during different seasons. MATERIAL AND METHODS Isolation of full grown castor (Figure 1) leaf surface mycoflora from the sampling field was done by Serial Washing Technique (Kamal and Sing, 1970) on Czapek Dox Agar media during two different seasons. Fresh tender and mature leaves were collected randomly and leaf disc were cut out from each category of leaves (1cm²) with the help of sharp sterilizes borer. Pieces of different categories of leaves were placed separately in 20 ml sterilized distilled water in 100ml Erlenmeyer flasks and were shaken for 20 min on a shaker (120 rpm). The process was repeated for 5 times and each time the washed leaf pieces were transferred to fresh sterile tube using sterile forceps. 1ml of each washing was transferred to petriplates containing 20ml Czapek dox agar media and incubated at 28±1 C in BOD incubator for a weak. Each treatment contains three replications and observation of different fungi colonies was made after 4 days of incubation and counts the colony number in the colony counter. During this period monthly meteorological data viz. temperature, relative humidity

3 Borgohain et al. 83 Figure 2. Fungal spore and conidiophores (A- Fusarium sp; B-Alternaria sp.; C- Curvularia sp; D-Penicillium sp). Figure 3. Seasonal occurrence of different fungal species (CFU/cm 2 ) in the phylloplane of tender and mature leaves of castor

4 Scholarly J. Agric. Sci. 84 Figure 4. Meteorological parameters during two different seasons (winter and summer). and rainfall were also recorded. Identification of different fungal colonies was done based on colony characteristics and spore morphology as per method and the keys described by Gregory (1973) and Tilak (1989). RESULTS AND DISCUSSION The results indicated that a total of 11 species of fungi from different groups were isolated altogether in winter and summer seasons. The study also reveals that the maximum numbers of fungal colonies were isolated in the month of April (168.3 CFU/cm 2 ) followed by March (151.4). The minimum numbers of colonies were recorded in the month of January, December and February 2013 (84.1, 91.3, and 95.8). Alternaria ricini (81.8 CFU) was found to be the most abundant species during the summer season followed by Cercospora ricinela (75.1) and Penicillium sp (69.6) respectively. During the winter season the species Emericella nidulans (83.3CFU) was found to be the most abundant species, whereas Fusarium sp (74.1) occupied the second position followed by and Melampsora ricini (63). A total of 11 species viz. A. ricini, Aspergillus fumigates, C. ricinela, Curvularia lunata, Fusarium sp, F. moniliform, Phytopthora parasitca and Penicillium sp were reported in the summer season (Figure. 2, 3 and 4)). On the other hand E. nidulans, Leveillula taurica, M. ricini were mainly found in the winter season. Other species were common during both the seasons (Table 1). The study reveals that the most abundant species of A. ricini is frequently distributed throughout the year but it shows higher abundance in summer than winter possibly due to suitable optimal temperature, humidity, rainy weather and greater soluble nutrient availability. Khara and Singh (1981) have also studied the seasonal fluctuation and behaviour of fungi on leaves in relation to meteorological factors and the found similar results (figure 5). The presence of maximum number of fungi in the month of March and April may be due to greater multiplication of micro-organism with the availability of sufficient nutrition and other CONCLUSION The study reveals that the number and abundance of mycoflora isolated from the phylloplane of R. communis varied according to seasonal changes in meteorological and availability of nutrition. A. ricini was predominant between all isolated fungi. Further pathogenic studies of this fungus will also be a great importance because among these species A. ricini is responsible for Alternaria blight of castor; P. parasitica for seedling blight; L. taurica for powdery mildew and C. ricinella for leaf spot disease, M. ricini for leaf rust disease (Saha, 2002). The systematic studies will lead to the illustration of identification characters of pathogenic fungus occurring in castor ecosystem. The systematic characters will help to develop diagnostic keys supplemented with information on symptoms of diseases, its extent of damage, life cycle, and distribution and management strategies. These information will provide basic information to the

5 Borgohain et al. 85 Table 1: Seasonal occurrence of different fungal species (CFU/cm 2 ) in the phylloplane of tender and mature leaves of castor Fungal species Types of Summer season Winter season leaf March April May June Mean STDV Nov Dec Jan Feb Mean STDV Alternaria ricini Tender Mature Aspergillus fumigatus Tender Mature Cercospora ricinela Tender Mature Curvularia geniculata Tender Mature Fusarium sp Tender Mature Fusarium moniliform Tender Mature Leveillula taurica Tender Mature Phytopthora parasitca Tender Mature Penicillium sp Tender Mature ` Melampsora ricini Tender Mature Emericella nidulans Tender Mature researchers for controlling the fungal disease in castor plant. ACKNOWLEDGEMENT The authors are highly grateful to the Department of Biotechnology (DBT), Government of India, and New Delhi for financial assistance in the form of a research project and also to the Director of CMER and TI, Lahdoigarh, Jorhat for providing necessary laboratory facilities for the work. REFERENCE Alamiri, S.A. (2008). Epiphytic Microflora on the leaves of Juniperus procera from aseer region, Saudi Arabia. J. Biol. Sci. 8(5) Andrews, J.H. and Harris R.F. (2000). The ecology and biogeography of microorganisms on plant surfaces.annu. Rev. Phytopathol., 38(1): Bakkar, G.R., Frampton,C.M., Jaspers, M.V., Stewart, A. and Walter, M. (2002). Assessment of Phylloplane micro- organism populationsin Canterbury apple orchards. N.Z. Plant Protect., 55: Blakeman, J.P. (1993). Pathogens in the foliar environment. Plant Pathol., 42(4): Das R, Das K (2005) Enemies of castor (Ricinus communis L); Euphorbiaceae) in geographical condition of Assam. Indian Silk, Dix, N.J. and Webster, (1995). Fungal Ecology. Chapman and Hall, London, pp: 549 Gregory (1973) and Tilak (1989).The microbiology of atmosphere Leonard (Hill Books) Limited,London Kamala and Sing, C.S (1970). Succession of fungi on decaying leaves of some pteridophytes.in:imprine avee periodique Annalese L.Institute Pasteur,No.ordre 4474

6 Scholarly J. Agric. Sci. 86 Tome.119: Khara, H.S. and Singh J. (1981). Phylloplane mycoflora of two varieties of tomato. Indian Phytopath, 34(4): Lewis, W.H and Elvin-Lewis, M.P.F. (1977). Medical Botany: Plants Affecting man s Health. John Wiley and Sons New York. Lindow S. E. and Brandl M. T., Microbiology of the Phyllosphere: MINIREVIEW Appl. & Environ. Microbiol., 69(4): Maji, M.D., Qadri, S.M.H. and Pal, S.C. (2003). Evaluation of mulberry phylloplane microorganisms for biological control of bacterial leaf spot of mulberry caused by Xanthomonas campestris pv. mori. Indian J. Agric. Res., 37(4): Phillips, R. and Martyn, R. (1999). Annuals and Biennials. London: Macmillan. p.106. Popova, E.V. (1963). Castor Oil plant, Lenin Academy of Agriculture Scientific and Industrial Application. Botany Men, Culture Lenin, U.S.S.R. Saha. L.R. (2002). Handbook of Plant Diseases, Kalyani Publishers, New Delhi. pp Simpson, B.B. and Ogorzaly, M.C. (1986). Economics Botany: Plants in our World. M. C Graw-Hill, New York. Tilak, S.T. (1989) :Air borne pollen and fungal spores Vaisjanti prakashan Aurangabad pp: Weiss, E. A. (1983). Oil Seed Crops. Tropical Agricultural Science, Longman London Zahir, A.A., Rahuman, A.A., Bagavan, A., Santhoshkumar, T., Mohamed, R.R., Kamaraj, C., Rajakumar, G., Elango, G., Jayaseelan, C. and Marimuthu, S. (2010). Evaluation of botanical extracts against Haemaphysalis bispinosa Neumann and Hippobosca maculata Leach" Parasitol. Res. 107:3 ( ).