Identification of the Region Encoding Opine Synthesis and of a Region Involved in Hairy Root Induction on the T-DNA of Cucumber-Type Ri Plasmid. Jean Brevet. Institute de Microbiologie, Bât 409, Université de Paris-Sud, 91405 Orsay, France. Denise Borowski, and Jacques Tempé. Institute de Microbiologie, Bât 409, Université de Paris-Sud, 91405 Orsay, France.. MPMI 1:75-79. Accepted 29 December 1987. Copyright 1988 The American Phytopathological Society.

Partial digestion products from a plasmid extending over the entire T-DNA region of the cucumber-type Ri plasmid have been cloned on the wide host range plasmid pRK404. Recombinant plasmids were introduced by triparental mating in Agrobacterium strains carrying disarmed Ti plasmids. Two constructs, pMOA3 and pMOA4, were able to incite hairy roots on carrot disks. They were mutagenized by transposon (Tn7) insertion, and deletions were created in the T-region. The resulting plasmids were studied for their ability to trigger root formation or opine synthesis. Opine synthesis gene(s) and one region involved in induction of hairy roots on carrot disks were identified.