A glyphosate-tolerant chicory callus (R1) was selected by a stepwise procedure. It had ability to tolerate a glyphosate concentration 25 times higher than that inhibiting the wild-type callus. Tolerance was associated with a 4.4-fold elevated level of 5-enol-pyruvyl-shikimate-3-phosphate (EPSP) synthase (EC 2.5.1.19) in the selected callus compared to the wild-type. EPSP synthases from glyphosate-tolerant and sensitive calli were similarly inhibited by glyphosate. Plants regenerated from R1 callus also had enzyme levels higher than those of sensitive plants, although the 2.5-fold difference was less pronounced. Callus derived from these regenerated resistant plants retained partial tolerance (18-fold) and possessed an increased EPSP synthase specific activity (3.3-fold greater than the control). As the R1 plants were self-incompatible, seeds were obtained by crossing with the wild-type; the plants of the G1 generation were sensitive to glyphosate. The lack of inheritance of herbicide tolerance may be due to recessiveness or to epigenetic inheritance.
Glyphosate tolerance in Cichorium intybus L. var. Magdebourg
FORLANI, Giuseppe;
1992
Abstract
A glyphosate-tolerant chicory callus (R1) was selected by a stepwise procedure. It had ability to tolerate a glyphosate concentration 25 times higher than that inhibiting the wild-type callus. Tolerance was associated with a 4.4-fold elevated level of 5-enol-pyruvyl-shikimate-3-phosphate (EPSP) synthase (EC 2.5.1.19) in the selected callus compared to the wild-type. EPSP synthases from glyphosate-tolerant and sensitive calli were similarly inhibited by glyphosate. Plants regenerated from R1 callus also had enzyme levels higher than those of sensitive plants, although the 2.5-fold difference was less pronounced. Callus derived from these regenerated resistant plants retained partial tolerance (18-fold) and possessed an increased EPSP synthase specific activity (3.3-fold greater than the control). As the R1 plants were self-incompatible, seeds were obtained by crossing with the wild-type; the plants of the G1 generation were sensitive to glyphosate. The lack of inheritance of herbicide tolerance may be due to recessiveness or to epigenetic inheritance.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
