The ASYMMETRIC LEAVES1 and ASYMMETRIC LEAVES2 genes which are involved in the flat and symmetric leaf development regulate multiple gene pathways

Abstract

Leaves are generated as lateral organs from a shoot apical meristem and develop along three axes, proximal-distal, adaxial-abaxial and medial-lateral axes. The ASYMMETRIC LEAVES1 (AS1) and AS2 of Arabidopsis thaliana play important roles to establish these axes to produce flat and symmetric leaves. Microarray analysis using Knowledge-based FuzzyART method, which we developed, revealed that AS1 and AS2 repress not only the class 1 KNOX genes but the abaxial genes ETTIN (ETT) and YABBY5 (YAB5). Levels of expression of BP, ETT and YAB5 in as2 bp knat2 knat6 quadruple mutant and as2 ett arf4 triple mutant were quantified by real-time PCR and revealed that BP and ETT were down-regulated by AS2 in the ett arf4 and bp knat2 knat6 mutants, respectively and that YAB5 were down-regulated in both mutants. Our results suggested that by the repression of the multiple pathways AS1 and AS2 regulate flat and symmetric leaves.