Date of Publication

4-30-2009

Document Type

Master's Thesis

Degree Name

Master of Science in Biology

Subject Categories

Bacteria | Biology

College

College of Science

Department/Unit

Biology

Thesis Adviser

Anthony C. Lee

Defense Panel Chair

Esperanza C. Cabrera

Defense Panel Member

Marian A. Pulido
Glenn G. Oyong

Abstract/Summary

Thirty three (33) bacterial isolates were obtained from Cycas riuminiana root nodules using congo red-yeast extract mannitol agar (CR-YEMA) as the primary isolation medium. These isolates were characterized in terms of their morphological and biochemical characteristics. Colonial morphologies of the isolates were described after growing them in CR-YEMA after five days of incubation at room temperature. Five colony types were observed among the isolates derived from the root nodules. Majority (19/33) of the isolates yielded red, undulate, wrinkled, dry, large opaque, raised, irregular colonies while less than a quarter (7/33) exhibited white, entire, glistening, butyrous, pinpoint, opaque, convex, circular colonies. More than a quarter (26/33) of the isolates were Gram positive while the rest (7/33) were Gram negative bacilli. Most of the isolates were motile (30/33), catalase positive (33/33), oxidase positive (23/33), and can utilize citrate (30/33) as carbon and energy source. Bacterial isolates were identified using 16S rD A sequence analysis. Rhizobial and non-rhizobial species thrived in the root nodules. The rhizobial species include Bradyrhizobium sp., Bradyrhizobium japonicum, Mesorhizobium sp. and Rhizobium sp. The non-rhizobial species predominantly were soil bacteria which include Bacillus spp. (B. megaterium, B. subtilis and B. amyloliquefaciens), Lysinibacillus sphaericus, Paenibacillus sp., Paenibacillus thailandensis, Friedmanniella sp., and Microbacterium sp. One out of the thirty three isolates yielded an amplicon corresponding to the nodA gene. This isolate designated as EXN24 was identified as Mesorhizobium sp., a rhizobial species.

Abstract Format

html

Language

English

Format

Electronic

Accession Number

CDTG004696

Shelf Location

Archives, The Learning Commons, 12F Henry Sy Sr. Hall

Physical Description

viii, 78 leaves

Keywords

Root-tubercles; Bacteria

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