Live and let dry: Tripogon loliiformis regulates autophagy to suppress cell death and tolerate desiccation

B Williams1, I Njaci1, L Moghaddam1, H Long1, M Dickman2, X Zhang3 and S Mundree1

  1. Centre for Tropical Crops and Biocommodities, Queensland University of Technology, Brisbane, QLD, Australia
  2. Department of Plant Pathology and Microbiology, Institute for Plant Genomics and Biotechnology, Texas A&M University, College Station, TX, USA
  3. Department of Biochemistry and Biophysics, Institute for Plant Genomics and Biotechnology, Texas A&M University, College Station, TX, USA

Over the next fifty years there will be a massive challenge to sustain an ever-increasing global population which is predicted to peak at 9 billion people in 2050. Further compounding this burgeoning population, climate-change forecasts predict increasing erratic weather globally and reduced crop yields in future environments. How do we fulfil this ensuing supply-demand gap? A small group of angiosperms termed resurrection plants have the ability to tolerate desiccation and return from a dormant state upon watering and may serve as a unique genetic resource for the generation of resilient crops that can survive and yield during unfavourable conditions. Here, we use, Tripogon loliiformis, a native Australian resurrection plant to answer the intriguing question of how resurrection plants maintain vitality in desiccated tissues? We show that T. loliiformis utilises a unique regulatory role for the non-reducing sugar trehalose in the activation of autophagy pathways during drying. Transcriptome, Gas Chromatography Mass Spectrometry and confocal microscopy analyses correlated trehalose accumulation with the onset of autophagy in dehydrating T. loliiformis shoot tissues. These results were supported in vitro with the observation of autophagy in hydrated T. loliiformis leaves following treatment with a 25 mM trehalose solution. Autophagy can promote survival of cells by removal of damaged organelles and misfolded proteins to suppress PCD and nutrient recycling to delay the onset of senescence. These findings illustrate how resurrection plants manipulate sugar metabolism to survive desiccation and may provide potential targets for the development of stress tolerant crops.