Poster: Regulation of gene expression
Abs #
770: Cloning and expression patterns of tissue culture responsive genes of peanut
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Presenter: |
Kudithipudi, Chengalrayan , chengal@ufl.edu |
Authors | Kudithipudi, Chengalrayan (A) Gallo-Meagher, Maria (A) | | Affiliations: |
(A): Agronomy Deaprtment, University of Florida
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Somatic embryogenesis and organogenesis of peanut were induced from the same explant, mature zygotic embryo-derived leaflets (MZELs), depending on the medium used for culture. Histological studies revealed that both somatic embryos and organogenic buds developed directly from the subepidermal layers of MZELs. Initially, MZELs underwent anticlinal division when cultured on MS medium containing 20 mg/l 2,4-D giving rise to somatic embryos. Interestingly, MZELs underwent periclinal division when cultured on MS medium containing 4 mg/l NAA and 5 mg/l BAP which resulted in organogenesis. To understand early initiation of these two developmental pathways, we have used differential display of mRNA to identify genes that are induced by the media composition. Since, cell division of MZELs on embryogenic medium was observed as early as the 3rd day and on organogenic medium on the 6th day, we isolated mRNA from 2d-old MZELs on embryogenic medium, and 2d- and 6d-old MZELs on organogenic medium. MZELs cultured on MS medium alone for 2d were used as controls. cDNA was synthesized using oligo dT primers. PCR was performed with factorial combinations of three anchored primers and sixty-four random primers for a total of 192 reactions. Fifty-one differentially expressed genes were cloned and sequenced. Putative identification of these cDNAs by comparison to known sequence data has allowed us to infer some of the biochemical and molecular processes that are altered in the response of MZELs to tissue culture media. Expression of these clones was confirmed by northern analysis, and transcripts isolated at different time intervals during somatic embryogenesis and organogenesis were used to reveal the gene expression patterns of individual clones.
