Ricerc@Sapienza

During organogenesis, coherent organ growth arises from spatiotemporally coordinated decisions of individual cells. In the root of Arabidopsis thaliana, this coordination results in the establishment of a division and a differentiation zone. Cells continuously move through these zones; thus, a major question is how the boundary between these domains, the transition zone, is formed and maintained. By combining molecular genetics with computational modeling, we reveal how an auxin/PLETHORA/ARR-B network controls these dynamic patterning processes.

A clear example of interspecific variation is the number of root cortical layers in plants. The genetic
mechanisms underlying this variability are poorly understood, partly due to the lack of a convenient
model. Here, we demonstrate that Cardamine hirsuta, unlike Arabidopsis thaliana, has two cortical
layers that are patterned during late embryogenesis. We show that a miR165/6-dependent
distribution of the HOMEODOMAIN LEUCINE ZIPPER III (HD-ZIPIII) transcription factor

A key question in biology is to understand how interspecies morphological diversities originate. Plant roots present a huge interspecific phenotypical variability, mostly because roots largely contribute to adaptation to different kinds of soils. One example is the interspecific cortex layer number variability, spanning from one to several.

Soil pollutants may affect root growth through interactions among phytohormones like auxin and jasmonates.Rice is frequently grown in paddy fields contaminated by cadmium and arsenic, but the effects of these pollutants on jasmonates/auxin crosstalk during adventitious and lateral roots formation are widely unknown. Therefore, seedlings of Oryza sativa cv.

Nitric oxide (NO) has signalling roles in plant stress responses. Cadmium (Cd) and arsenic (As) soil pollutants alter plant development, mainly the root-system, by increasing NO-content, triggering reactive oxygen species (ROS), and forming peroxynitrite by NO-reaction with the superoxide anion. Interactions of NO with ROS and peroxynitrite seem important for plant tolerance to heavy metal(oid)s, but the mechanisms underlying this process remain unclear.