GENETIC DIVERSITY AND STRAIN IMPROVEMENT IN Pleurotus ostreatus

Abstract

newline Department of Plant Pathology newlineCSK Himachal Pradesh Krishi Vishvavidyalaya newlinePalampur-176062 newline newlineTitle of the thesis : Genetic diversity and Strain Improvement in Pleurotus ostreatus. newlineName of the student : Rishu Sharma newlineAdmission No. : A-2007-40-04 newlineMajor subject : Plant Pathology newlineMinor subject : Agricultural Biotechnology, newlineCrop Improvement newlineDate of thesis submission : July, 2012 newlineTotal pages in thesis : newlineMajor Advisor : Dr. B.M Sharma newline newlineABSTRACT newlinePleurotus mushroom is referred to as Oyster Mushroom and is a lignocellulosic fungus. The species of genus Pleurotus show great diversity in their adaptation to varying agro-climatic conditions. A total of 31 isolates of Pleurotus were procured/collected from different sources/locations, for conducting studies on morphological aspects, strain improvement and genetic diversity. A temperature range of 25-28oC was recorded to be optimum for majority of the isolates. Morphological features in relation to shape, size, colour and texture of the pileus, stipe length, spore print and size of basidiospores showed considerable variations among all the isolates. Strain improvement in Pleurotus ostreatus was carried out using physical (UV light) and chemical mutagen ( EMS). Strain improvement in three isolates of P.ostreatus viz. PO-2, PO-6 and PO-7 using physical (UV light) and chemical mutagen (EMS) resulted in mutants showing retarded mycelial growth in PO-7(U4), PO-2(E3) and PO-2(E4). PCR amplification based on domain specific markers for V6 and V9 domains of mitochondrial SSU rDNA of 12 test isolates belonging to 9 Pleurotus spp. resulted in single amplicon of approximately 170 and 300 bp size. Consensus tree generated after alignment of V6 and V9 domains of 12 isolates using both NJ and UPGMA methods differentiated the isolates into two major groups. SSR analysis using five 18-mer primers viz. GBPO025, GBPO064, GBPO149, GBPO157 and GBPO171 producing consistent polymorphic banding pattern showed a wide variation among various test isolates of Pleurotus ostreatus. Amplification of 5 portion of 26S ribosomal DNA of Pleurotus species/strains using pair primers LROR and LR7 yielded a fragment of 1460 bp in all the 31 isolates of Pleurotus. PCR-RFLP analysis of the amplified product using eight restriction enzymes viz. EcoR I, Hha I, Bsp I, Dra I, Taq I, Alu I, Msp I, and Hinf I resulted in 3, 3, 4, 3, 7, 5, 3, 2 bands, respectively. However, no inference was drawn with respect to division of various species isolates into a specific species group or clades. newline___________________ _____________________ newline(Rishu Sharma) (Dr. B.M. Sharma) newline Student Major Advisor newline newline ________________ newline Head of Department newline