Lettuce plants that overexpress the KNAT1 homeotic gene from Arabidopsis thaliana exhibit alteration in bolting and flower differentiation

Lettuce plants, that overexpress the KNAT1 homeobox gene from Arabidopsis (PetE::KNAT1), display a wide range of effects on both leaf and whole plant architecture. Leaf vein network changes dramatically with profound effects on the whole leaf morphology and shape. The leaf vascular cell fate itself shifts from determinate to indeterminate, giving rise to leaf-like structures at the leaf margins. These effects have been related to the overproduction of specific cytokinins that is associated to the overexpression of KNAT1. PetE::KNAT1 transgenics also display anticipated inflorescence stem elongation and flowering response. Here we describe in detail the effects of KNAT1 on flowering and discuss about the possible role of homeotic knotted-like genes in phase change.