Thesis Title

Expressed Sequence Tag and Rna Hybridization Analysis of Phenol Biosynthesis Genes in Grapevine

Date of Graduation

Fall 2003

Degree

Master of Science in Plant Science

Department

Biology

Committee Chair

Laszlo Kovacs

Subject Categories

Plant Sciences

Abstract

To gain insight into the molecular basis of phenol biosynthesis in grapevine, expressed sequence tabs (ESTs) were generated from Vitis aestivalis var. Norton. The processing of 1920 leaf-derived randomly selected cDNA clones yielded 1510 high-quality ESTs which could be assembled into 189 contigs and 722 singletons. The putative functions for these ESTs were predicted by sequence similarity searches. Based on these search results, the ESTs were classified into 11 functional categories, the majority of which represented genes involved in photosynthesis (24%) and general metabolism (17%). Phenol biosynthesis-related genes accounted for 2% of the total ESTs. The nucleic acid sequence homology between V. aestivalis phenol biosynthesis-related ESTs and corresponding Vitis vinifera orthologs ranged from 62 to 98%, which reflected sequence divergence for some, but not all of these genes. RNA slot blot assays of selected phenol biosnythesis-related genes demonstrated that their transcript levels in young leaves were similar between the two species as well as among the leaves of different developmental stages in V. vinifera. Thus, the higher disease-resistance in V. aestivalis and the ontogenic-resistance in V. vinifera leaves may not be due to differential expression of the early genes in the phenol biosynthesis pathway.

Copyright

© Turlapati V. Phanikanth

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