Stable male sterility induced by the expression of mutated melon ethylene receptor genes in Nicotiana tabacum.

A major concern about genetically modified crops is transgene flow through pollen dispersal. We previously demonstrated that overexpression of the mutated melon ethylene receptor genes Cm-ETR1/H69A or Cm-ERS1/H70A induces pollen abortion and altered flower architecture, resulting in sterility or reduced fertility in transgenic tobacco plants. To investigate the stability of these traits, three transgenic tobacco lines in which Cm-ETR1/H69A or Cm-ERS1/H70A confer sterility or reduced fertility were grown in a greenhouse with environmental conditions that changed, depending on the outside conditions. During the growth of the plants, the temperature ranged from 31°C at the beginning of September to 17°C at the beginning of November. The light provided was natural sunlight. The first group of plants flowered in late September, and the second group flowered in late October. The wild-type plants showed the homostyly type of floral architecture, whereas, three transgenic lines showed the heterostyly type. The floral architecture was stable during the different flowering periods. Pollen production was significantly reduced in two transgenic lines and completely aborted in one transgenic line, and these traits were also stable during the different flowering periods. These results suggest that the sterility or reduced fertility induced by the expression of mutated melon ethylene receptor genes in transgenic tobacco plants is stable under varying environmental conditions.