Modulation of the balance between stem cell proliferation and consumption by ERECTA-family genes.

Stem cells in the vegetative shoot apical meristem proliferate to produce more stem cells (self-renewal) and are simultaneously consumed to form leaf promordia. Therefore, to keep a stable number of stem cells, regulation of the balance between their proliferation and consumption is important. Recently we reported that stem cell population is increased in mutant plants lacking the entire ERECTA (ER) receptor kinase family. Here we describe that loss of function of the entire ER-family causes a decrease in leaf number in spite of the increase in stem cell population. This suggests that stem cell consumption might be decreased in the mutant, and this could be one of reasons why stem cell population appears to be increased. This situation is in sharp contrast to clv3 mutant, which also shows an increase in stem cell population but does not show a decrease in leaf production. We briefly discuss differences between the er-family mutant and the clv3 mutant.