of Tobacco (Nicotiana tabacum L.) D.V. Subhashini and Raghvendra P. Singh*. Central Tobacco Research Institute, Rajahmundry-533 105, India, *NBAIM, Mau, ...
Short Communication
Isolation of endophytic actinomycetes from roots and leaves of Tobacco (Nicotiana tabacum L.) D.V. Subhashini and Raghvendra P. Singh* Central Tobacco Research Institute, Rajahmundry-533 105, India, *NBAIM, Mau, U.P
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Date of Receipt: 16.05.2014; Accepted: 24.06.2014
Endophytic microorganisms are those which inhabitat the internal part of plants, causing apparently no visible changes to their hosts. Although known since long time, their importance become evident only more recently when it was shown that they play specific roles (protecting the host-plants against insects & diseases). Actinomycetes are bacteria known to constitute a large part of the rhizosphere microbiota (Subhashini & Padmaja, 2009). Their isolation is an important step for screening of new bioactive compounds. They are also found inside plants but, excluding the coryneform bacteria, the only extensively studied species are from the genus Frankia, a nitrogen fixing bacteria of non-leguminous plants. The present work was carried out to isolate actinomycetes from roots and leaves of tobacco, were screened for antibiotic production against fungi and three bacteria. Tobacco plants cv. VT-1158 were sampled 30 and 45 days after transplantation. Only plants
exhibiting healthy vegetative growth were used. Six leaves and six segments of roots from each location were washed in water following surface sterilization with ethanol 70% for 30 seconds and then, treated with sodium hypochloride (3-5% available chlorine) for 3 min. Root and leaf fragments were aseptically transferred to Petri dishes containing starch-casein-agar medium and 2.5% water-agar medium (Subhashini, 2013). Plates were incubated at 28oC for a maximum of three days. Actinomycetes were observed emerging from roots and leaves segments of plants sampled 45 days after transplantation. From a total of 36 isolates, 44.4% were obtained from leaves and the remaining 55.6% from roots. The most frequent genus was Streptomyces (12 isolates from leaves & 18 isolates from roots) followed by Nocardia (4 isolates from leaves & 2 from roots). The remaining 20 isolates
Table 1. Antimicrobial activity of endophytic actinomycetes isolated from tobacco against bacteria and fungi. Genera
Isolates*
Streptomyces L2, L4, L9 L13, L18, L20 R7, R9, R11, R15, R17, R20 L16, R1 Nocardia L26, L28 L31, L36 R35, R33 L29, L27
S. aureus**
E. coli
B. subtilis
P. aphanidermatum
+
+
+
+
+ + + + – – +
+ – – – + – +
– + + + – + –
+ + – – + + –
*L are isolates from leaves and R are isolates from roots; **+ and - = inhibition and absence of inhibition respectively
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Ann. Pl. Protec. Sci. 22 (2) : 422-460 (September, 2014)
Short Communication
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never bore reproductive structures and could not be identified. From 36 isolates tested against bacteria and P. aphanidermatum, most of the isolates presented antimicrobial activity against one or more microorganisms used. Antimicrobial activity was also found in endophytic actinomycetes (Subhashini & Padmaja, 2009) and thus, in may play a role in protecting the plant host against pathogenic microorganisms. The results showed that actinomycetes can be isolated as endophytes not only inside tobacco roots but also inside leaves (Subhashini et al., 2014). Several reports refer to actinomycetes acting in plant protection against pathogens and the influence of their metabolic products on tobacco plant growth (Subhashini, 2012). In the present work, the presence of actinomycetes inside roots and leaves of a widely cultivated tobacco crop in TBS and NLS was confirmed. Certain genera isolated as
tobacco endophytes were also found in the roots of plants from temperate climate. Subhashini and Padmaja (2011) also reported similar results. References Subhashini, D.V. and K. Padmaja (2011). Antagonistic activity of bacterial isolates collected from tobacco soils. Ann. Pl. Protec. Sci. 19: 451-452. Subhashini, D.V. (2012). The antimicrobial activity of Streptomyces spp. obtained from tobacco (Nicotiana tabacum L.) soils. Ann. Pl. Prot. Sci. 20: 254-255. Subhashini, D.V. (2013). Effect of different media on the growth of Streptomyces sp. Ann. Pl. Prot. Sci. 21: 449-450. Subhashini, D.V., T. Ravi Chaitanya, J. Vasanthi and G. Arvind Kumar (2014). Detection of seed borne fungi associated with Nicotiana tabacum seeds. Ann. Pl. Protec. Sci. 22: 220-221.
Nematicidal efficacy of bioagents, botanicals and phorate on Mung bean Archana U. Singh and D. Prasad AICRP (N), Division of Nematology, I.A.R.I., New Delhi - 110 012, India Date of Receipt: 04.07.2014; Accepted: 15.07.2014 The mungbean, Vigna radiata (L.) Wilczek, one of the important pulse crops, was grown in India since ancient time. All types of plant parasitic nematodes are causing damage at all stages of growth. However, this was pertinent to manage the nematode associated with mung crop (Singh & Prasad 2014). Hence, the present study on use of fungal bioagents, botanicals and a systemic nematicide was evaluated against plant parasitic nematodes on mung crop. A field trial was carried out in the microplots 16m2 on mungbean cv. PUSA-9531 against plant
parasitic nematodes. The initial infestation of the plant parasitic nematodes in the field was Meloidogyne incognita, Rotylenchulus reniformis, Tylenchorhynchus indicus, and Hoplolaimus indicus - 400, 150, 250 and 200 in 200 g soil, respectively. The treatments were: T1 Aspergillus niger @ 5 kg/ha having a spore load of 2 × 109 spores/g, T2 - Paecilomyces lilacinus @ 5 kg/ha (2 × 109 spores/g), T3 - NSKE @ 2 q/ ha, T 4 - chopped fresh leaves of Calotropis procera @ 1 kg/microplot, T5 - phorate @ 1 kg a.i./ha, as soil application and T6 - check (without treatment). All the microplots were divided into 5
Ann. Pl. Protec. Sci. 22 (2) : 422-460 (September, 2014)
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