Genetic and molecular networks regulated by ASYMMETRIC LEAVES1 and ASYMMETRIC LEAVES2 for leaf development in Arabidopsis: KNOX genes control at least five morphological events

Abstract

The asymmetric leaves1 (as1) and asymmetric leaves2 (as2) mutants of Arabidopsis exhibit pleiotropic phenotypes. Mutant leaves have asymmetric lobes; they have a short petiole and lamina, and a thin and distinct midvein. They also have simplified higher-ordered veins. Culture of sections of mutant leaves on phytohormone-free medium reveals a reduced potential for regenerating roots and an enhanced potential for regenerating shoots. Mutant sepals and petals are also short. The flowering of mutant plants is delayed and there is a slight decrease in the adaxialization of leaves. A number of genes, including class 1 KNOTTED-like homeobox (KNOX) genes, are upregulated in these mutants. we introduced monogenic, double and triple loss-of-function mutations in KNOX genes into as1 and as2 mutants and investigated their phenotypic effects and the changes in patterns of expression of the AtGA20ox1 and AtIPT7 genes.