Michael Raissig: Form, Development and Function of Plant Stomata
14:00 - 15:00
Centre for Organismal Studies, Heidelberg University, Heidelberg, Germany
Plants optimize carbon assimilation while limiting water loss by adjusting stomatal aperture. In grasses, the addition of subsidiary cells (SCs) flanking two dumbbell-shaped guard cells (GCs) results in an innovative stomatal morphology that is supposedly linked to the grass family's improved gas exchange efficiency. A mutant screen in the model grass Brachypodium distachyon identified a transcription factor required for SC formation. Unexpectedly, the transcription factor is an ortholog of the stomatal regulator AtMUTE, which defines GC precursor fate in Arabidopsis. The novel role of BdMUTE in specifying lateral SCs appears linked to its acquisition of cell-to-cell mobility in Brachypodium. Physiological analyses on bdmute mutant plants lacking SCs experimentally support classic hypotheses that SCs permit greater stomatal responsiveness to enhance water use efficiency. Recently, we profiled the transcriptome of developing and mature leaf zones of both wild-type and SC-less bdmute plants to identify novel factors regulating SC development and SC function, respectively. In the future, we will apply a comparative morphology and development approach by studying model systems that produce diverse stomatal forms with distinct numbers and ontogenies of SCs. Understanding how diverse stomatal forms affect gas exchange dynamics of leaves might enable the engineering of SC properties in many different crops to improve water use efficiency and plant performance.