Poster: Transcription Regulation

Abs # 1070: Gene expression patterns of an avocado cytochrome P450 gene in transgenic arabidopsis

Presenter:	Bozak-Middleton, Kristin , kbozak@csupomona.edu
Authors	Bozak-Middleton, Kristin  (A)   Tang, Sopheap  (A)   Brown, Michael  (A)   Li, Rui  (A)
Affiliations:	(A): Calif. StatePolytechnic University, Pomona

Biosynthesis of the gaseous plant hormone ethylene is induced in climacteric fruit both during fruit ripening and wound-responses. We have previously characterized a ripening-and wounding-responsive gene from avocado, the cytochrome P450 gene, cyp71A1, and shown it is induced both during fruit ripening and wounding of both roots and leaves. Using the upstream region of the gene, we are currently attempting to locate the exact DNA nucleotides that are ethylene-responsive through the use of a transgenic system utilizing Arabidopsis plants that has been engineered to contain a cyp71pro/GUS chimera. These plants have been engineered to contain 1,050 bases of the CYP71A1 upstream region that controls the production of a reporter gene, â-glucoronidase (GUS). By ethylene gassing the transgenic plants, we have been able to determine that this 1-kilobase (kb) region is sufficient to fully activate the CYP71A1 promoter and induce GUS activity in the tissues of the plants. Mechanical wounding, salicylic acid application, and fungal infection all induced the activation of the gene upon the 1 h of the treatment. Our aim is to continue dissecting these 1,050 bases in order to locate the exact sub-domain that is responding to the ethylene. The ripening-specific promoter is becoming important to the production of transgenic plants for production of edible vaccines. Additionally through our understanding of the genetic regulation of ripening we will increase our ability to manipulate this process. This work was funded through a Mc Nair Scholar Program Award to ST, and an NIH-MBRS grant to KRB.