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MOLECULAR CHARACTERIZATION OF NATIVE ISOLATES OF ENTOMOPATHOGENIC FUNGI Beauveria bassiana (BALSAMO) VUILLEMIN

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Title MOLECULAR CHARACTERIZATION OF NATIVE ISOLATES OF ENTOMOPATHOGENIC FUNGI Beauveria bassiana (BALSAMO) VUILLEMIN
 
Creator BALA NAIK, R
 
Contributor MURALI KRISHNA, T
 
Subject animal developmental stages, biological phenomena, fungi, wood, fruits, beauveria bassiana, concentrates, sampling, pathogens, dna
 
Description A roving survey was carried out in three districts i.e. Chittoor, Anantapur and Kurnool districts of Rayalaseema region of Andhra Pradesh during rabi, 2011-2012 for the natural occurrence of entomopathogenic fungi, Beauveria bassiana on Lepidopteran caterpillars. Soil samples were also collected from the fields surveyed and a few fungal infected caterpillars of S. litura, H. armigera and Plusia were collected from groundnut fields of RARS Tirupati, Settivaripalli, Vadamalapeta, Vemapuram and Madibaka villages and cabbage field in Gangavaram. Two isolates of B. bassiana were isolated from soil samples collected from Tiruvattam and vadamalapeta villages. In some of the silkworm rearing units in Palamaner division (Gangavaram, Appinapalli, Konganapalli, Maredupalli, Yeduru, Byripalli and V. Kota), Madanapalli division (Kosuvaripalli and Taruguvaripalli), Nandyal division (Bheemavaram) and Hindupur a few fungal infected and dead (mummified) cadavers of B. mori were collected.
More than 50% mortality of all the three instar larvae (I, II and III) of S. litura was recorded with SGb and MKb strains of B. bassiana. The mean percent larval mortality of I, II and III instar S. litura was highest (76.29%)
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with isolate SGb followed by MKb strain (63.70%) at 1×1010 spores ml-1. Among 13 strains of B. bassiana at 1×108 spores ml-1, 6 strains recorded more than 50% mortality in I instar S. litura, 3 strains recorded more than 50% mortality in II instar S. litura and all thirteen strains showed less than 50% mortality in III instar S. litura. All 13 strains of B. bassiana recorded less than 50% mortality at 1×106 spores ml-1 in I, II and III larvae of S. litura.
Twelve native and one reference strain of B. bassiana were assayed at different spore concentrations (1×1010, 1×108, 1×106, 1×104 and 1×102 spores ml-1) to determine LC50 by probit analysis. The native strain SGb registered the least LC50 (5.2×106) and LC90 (1.1×1010) values in terms of spores ml-1 followed by native strain MKb in all three instars. The LT50 value for all 13 strains of B. bassiana were recorded at 1×1010, 1×108 and 1×106 spores ml-1 in three instars (I, II and III) of S. litura and the native strain SGb registered the least LT50 value (134.40) in terms of hours followed by native strain MKb among all the thirteen isolates.
Six random primers used for RAPD (OPAA-04, OPAA-06, OPAA-14, OPA-15, OPE-04 and UP-PCR) showed 100% polymorphism. Jaccard’s similarity co-efficient between the thirteen B. bassiana isolates produced 100% genetic variation in two isolates i.e. PAb and NBAII-b, closely followed by PAb and PMb (97.6%). In the resulted dendrogram SGb and Kb: Gb and Bb strains formed one cluster, NBAII-b and PMb form another group and remaining strains did not form any group.
Five effective and promising B. bassiana strains (SGb, MKb, Kb, Bb and Hb) were characterized using rDNA-ITS sequences. All the five strains of B. bassiana showed 100% homology with already submitted B. bassiana strain in NCBI GenBank. Phylogenic dendrogram exhibited B. bassiana strains Bb and Kb as distinct cluster compared to others, where as B. bassiana strains SGb, MKb and Hb formed one cluster, however SGb grouped into same clade with AB 027382 (IFO 4848) and FJ 755242 (CZ 590) which were isolated from China and Japan, respectively. Gene sequences of five native strains were deposited in NCBI Gene Bank, Bethesda, USA with the accession numbers: JX173280.1 (SGb, Bb1), JX313063.1 (MKb, Bb2), JX313064.1 (Kb, Bb3), JX313065.1 (Bb, Bb4) and JX313066.1 (Hb, Bb5).
 
Date 2016-06-16T15:28:36Z
2016-06-16T15:28:36Z
2012
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/67487
 
Language en
 
Relation D9346;
 
Format application/pdf
 
Publisher ACHARYA N.G. RANGA AGRICULTURAL UNIVERSITY