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UV-B stops plants chilling out in the sunshine

Kerry Franklin

Press release issued: 16 December 2016

Plants display dramatic stem elongation at warm temperatures. These responses are thought to facilitate leaf cooling by enhancing water loss from surface pores, termed stomata. New research from the Universities of Bristol and Glasgow has shown that these architectural responses are severely attenuated by low levels of UV-B present in sunlight.

Warm temperature- induced stem elongation requires synthesis of the plant growth hormone, auxin. The study, published today in Current Biology shows that UV-B, perceived by the photoreceptor UVR8, inhibits auxin synthesis by inhibiting the abundance and activity of a key transcription factor, PHYTOCHROME INTERACTING 4 (PIF4). This provides plants with an important braking mechanism, preventing excessive elongation growth which could lead to stem lodging and critical reductions in root and leaf biomass at high temperature.

Lead author, Dr Kerry Franklin, from the school of Biological Sciences, commented ‘excessive stem elongation can be a real problem for commercial horticulture. Understanding the molecular mechanisms through which stem is growth is controlled by environmental signals will enable us to provide glasshouse-based solutions to industry to help alleviate these issues’.

Further information

Hayes S, Sharma A, Fraser D, Trevisan M, Cragg-Barber CWK, Tavridou E, Fankhauser C, Jenkins G and Franklin K (2016). UV-B perceived by the UVR8 photoreceptor inhibits plant thermomorphogenesis. In Current Biology.