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Title: FACTORS INFLUENCING SHOOT REGENERATION AND B-GLUCURONIDASE EXPRESSION FROM 'ROYAL GALA' APPLE INTERNODES

Author
item LIU, QINGZHONG - USDA, ARS
item SALIH, SARBAGH - USDA, ARS
item Hammerschlag, Freddi

Submitted to: HortScience
Publication Type: Abstract Only
Publication Acceptance Date: 7/24/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Factors influencing regeneration and B-glucuronidase expression from apple (Malus X domestica Borkh.) stem internodes were studied as part of a program to develop transgenic 'Royal Gala' apple with improved disease resistance. The early stages of the transformation process were monitored by counting the number of B-glucuronidase (GUS) expressing zones immediately after co- cultivation of explants with Agrobacterium tumefaciens supervirulent strain EHA105 (p35SGUS_INT) and by counting the number of GUS expressing calli developing on explants two weeks after co-cultivation. Etiolated shoots were produced from in vitro shoots cultured for two weeks in the light followed by two weeks in the dark and were compared with shoots cultured for four weeks in the light (green shoots). First internodes from etiolated shoots produced three, 10 and 100 times the number of shoots regenerated from second, third and fourth internodal explants, respectively, and produced seven times the number of shoots compared with similar explants from green shoots. 100% of first internodes from etiolated shoots exhibited GUS expressing zones and yielded twice as many GUS expressing zones when compared with leaf explants from green shoots, which exhibited GUS expressing zones in only 60% of the explants. An average of nine GUS expressing calli per explant were produced on first internodes from etiolated shoots two weeks after co-cultivation.