The present invention provides novel DNA sequences coding for
protoporphyrinogen oxidase (protox) enzymes from soybean, wheat, cotton,
sugar beet, oilseed rape, rice, sorghum, and sugar cane. In addition, the
present invention teaches modified forms of protox enzymes that are
herbicide tolerant. Plants expressing herbicide tolerant protox enzymes
taught herein are also provided. These plants may be engineered for
resistance to protox inhibitors via mutation of the native protox gene to
a resistant form or they may be transformed with a gene encoding an
herbicide tolerant form of a plant protox enzyme. The present invention
further provides shuffled DNA molecules encoding protox enzymes having
enhanced tolerance to a herbicide that inhibits the protox activity
encoded by a template DNA molecule from which the shuffled DNA molecule
is derived.
