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ARS Home » Research » Publications at this Location » Publication #89250
Title: ETIOLATION OF 'ROYAL GALA' APPLE (MALUS X DOMESTICA BORKH.) SHOOTS PROMOTES HIGH FREQUENCY SHOOT ORGANOGENESIS AND ENHANCED B-GLUCURONIDASE EXPRESSION FROM STEM INTERNODES

Author
item LIU, QINGZHONG - CONTRACT EMPLOYEE
item SALIH, SARBAGH - CONTRACT EMPLOYEE
item Hammerschlag, Freddi

Submitted to: Plant Cell Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/5/1998
Publication Date: N/A
Citation: N/A

Interpretive Summary: Conventional breeding of apple is a slow, lengthy process due to its long juvenile period, high level of self-incompatibility and the highly heterozygous nature of the genome. The use of genetic engineering techniques has a promising potential for overcoming these problems by means of direct transfer of useful genes (e.g., for disease and pest resistance) to apple. Successful transformation depends on an efficient gene delivery system and on high frequency shoot regeneration from tissue cultures. To date, transformation frequency for apple has been very low (0.1- 1%). In this study, we report on factors that promote high frequency shoot regeneration from apple tissues and enhanced gene delivery to these tissues. This study will be of use to scientists interested in using gene transfer techniques to improve apple and related species.

Technical Abstract: Internodal explants from etiolated 'Royal Gala' apple shoots were compared with those from non-etiolated shoots, for frequency of shoot organogenesis and for efficiency of B-glucuronidase(GUS) expression after cocultivation of explants with Agrobacterium tumefaciens strain EHA105 (p35SGUSint). First (youngest) internodal explants from etiolated shoots produced 2, 10 and 100- fold numbers of shoots compared to second, third, and fourth internodal explants, respectively. Moreover, these explants produced 7-fold the number of shoots compared to similar explants from non-etiolated shoots. All first internodes from etiolated shoots exhibited GUS expressing zones and yielded 4-fold as many GUS expressing zones compared to commonly used leaf explants from non-etiolated shoots, which exhibited GUS expressing zones in only 63% of the explants. An average of 9.8 GUS expressing calli per explant were produced on first internodes from etiolated shoots two weeks after co-cultivation with A. tumefaciens.