Dynamic signalling network in plant responses to shade.

CASAL, JORGE JOSÉ

Villarrica

Conferencia; XII Reunión de Biología Vegetal de Chile; 2017

To take advantage of the resources provided by the environment, agricultural crops are cultivated at a high density of plants per unit soil surface. As a result of this condition, plants become exposed to mutual shading, which reduces yield per plant. Photo-sensory receptors such as phytochrome B and cryptochrome perceive the modifications of the light environment caused by the presence of neighbouring vegetation and initiate molecular modifications that generate growth responses. In turn, these reactions tend to mitigate the degree of mutual shading among plants. The early steps of these responses involve elevated levels of the growth hormone auxin. However, a more detailed analysis of the network reveals that, particularly under prolonged shade, the photosensory receptors have multiple points of action on auxin perception and signalling and on the action of other growth hormones. The latter involves organ-specific modifications of the dynamics of signalling components. This system-level modification generates a commitment that reinforces shade-avoidance responses.