Climate change leads to altered flowering pathway

Samarth S1, Jameson P1, Kelly D1, Lee R2, Macknight R2 and Turnbull M1

  1. School of Biological Sciences, University of Canterbury, Private Bag 4800, Ilam Christchurch, New Zealand.
  2. Department of Biochemistry, University of Otago, Dunedin, New Zealand.

Mast flowering is synchronised highly variable flowering by a population of perennial plants such as Chionochloa (Poaceae), over a wide geographical area. The ΔT model hypothesizes that the size of the temperature difference between successive summers determines each year’s flowering intensity. Currently, in model plant species we know that the flowering process is regulated by various transcription factors and micro-RNAs in response to a temperature change. GIGANTEA-HD1-Hd3a is the main flowering pathway conserved among the monocot species. The current study deals with the identification of a possible pathway controlling temperature-mediated masting in plants. By translocating plants we demonstrated that giving a large positive ΔT produces heavy flowering in Chionochloa which is sometimes premature (winter instead of summer). Gene expression studies suggest that the premature flowering could be an attribute of GIGANTEA-dependent but HD1-independent flowering pathway. RNA-seq was employed to identify the key flowering gene(s) involved. The RNA-seq data were validated using RT-qPCR in samples from flowering and non-flowering plants over an altitudinal range across seasons. The study suggests that a large positive ΔT can provoke heavy flowering through two different pathways, one of which results in premature flowering. The change in the flowering response can decrease the reproductive competency and reproductive output of a plant species. Such changes can have also contrasting effects on the interactions between plant species and suggest that global change may skew flowering patterns in mast seeding plants.