Editing Arabidopsis thaliana (section)

===Leaf development===
Studies of ''A. thaliana'' have provided considerable insights with regards to the genetics of leaf morphogenesis, particularly in [[Dicotyledon|dicotyledon-type]] plants.<ref>{{cite journal |vauthors=Tsukaya H |title=Leaf development |journal=The Arabidopsis Book |volume=11 |pages=e0163 |date=2013-06-07 |pmid=23864837 |pmc=3711357 |doi=10.1199/tab.0163}}</ref><ref>{{cite journal |vauthors=Turner S, Sieburth LE |title=Vascular patterning |journal=The Arabidopsis Book |volume=2 |pages=e0073 |date=2003-03-22 |pmid=22303224 |pmc=3243335 |doi=10.1199/tab.0073}}</ref> Much of the understanding has come from analyzing mutants in leaf development, some of which were identified in the 1960s, but were not analysed with genetic and molecular techniques until the mid-1990s. ''A. thaliana'' leaves are well suited to studies of leaf development because they are relatively simple and stable.

Using ''A. thaliana'', the genetics behind leaf shape development have become more clear and have been broken down into three stages: The initiation of the [[leaf primordium]], the establishment of [[dorsiventrality]], and the development of a marginal [[meristem]]. Leaf primordia are initiated by the suppression of the genes and proteins of class I ''[[Evolutionary history of plants|KNOX]]'' family (such as ''SHOOT APICAL MERISTEMLESS''). These class I KNOX proteins directly suppress [[gibberellin]] biosynthesis in the leaf primordium. Many genetic factors were found to be involved in the suppression of these class I ''KNOX'' genes in leaf primordia (such as ''ASYMMETRIC LEAVES1,'' ''BLADE-ON-PETIOLE1'', ''SAWTOOTH1'', etc.). Thus, with this suppression, the levels of gibberellin increase and leaf primordium initiate growth.

The establishment of leaf dorsiventrality is important since the [[Anatomical terms of location|dorsal]] (adaxial) surface of the leaf is different from the ventral (abaxial) surface.<ref>{{cite journal |vauthors=Efroni I, Eshed Y, Lifschitz E |title=Morphogenesis of simple and compound leaves: a critical review |journal=The Plant Cell |volume=22 |issue=4 |pages=1019–32 |date=April 2010 |pmid=20435903 |pmc=2879760 |doi=10.1105/tpc.109.073601}}</ref>