In vivo spectroscopy and NMR metabolite fingerprinting approaches to connect the dynamics of photosynthetic and metabolic phenotypes in resurrection plant Haberlea rhodopensis during desiccation and recovery.

Petko Mladenov,Vasilena Krasteva,Svetlana Simova,Daniela Moyankova,Magdalena Tchorbadjieva,Norbert Rolland,Giovanni Finazzi,Sabine Brugière,Richard Bligny,Anne-Marie Boisson,Myriam Ferro,Vasiliy Goltsev,Diana Zasheva,Kalina Alipieva,Dimitar Djilianov

doi:10.3389/fpls.2015.00564

Abstract

The resurrection plant Haberlea rhodopensis was used to study dynamics of drought response of photosynthetic machinery parallel with changes in primary metabolism. A relation between leaf water content and photosynthetic performance was established, enabling us to perform a non-destructive evaluation of the plant water status during stress. Spectroscopic analysis of photosynthesis indicated that, at variance with linear electron flow (LEF) involving photosystem (PS) I and II, cyclic electron flow around PSI remains active till almost full dry state at the expense of the LEF, due to the changed protein organization of photosynthetic apparatus. We suggest that, this activity could have a photoprotective role and prevent a complete drop in adenosine triphosphate (ATP), in the absence of LEF, to fuel specific energy-dependent processes necessary for the survival of the plant, during the late states of desiccation. The NMR fingerprint shows the significant metabolic changes in several pathways. Due to the declining of LEF accompanied by biosynthetic reactions during desiccation, a reduction of the ATP pool during drought was observed, which was fully and quickly recovered after plants rehydration. We found a decline of valine accompanied by lipid degradation during stress, likely to provide alternative carbon sources for sucrose accumulation at late stages of desiccation. This accumulation, as well as the increased levels of glycerophosphodiesters during drought stress could provide osmoprotection to the cells.

Highlights

Growth and yield of crop plants is severely hampered by drought
Evaluation of Leaf Water Status In the present study, the leaf water status was evaluated by comparing leaf WC and prompt chlorophyll fluorescence
We decided to apply a non-destructive sampling, using JIP-TEST derived from both Plant efficiency analyzers (PEA) devices, to better define the sampling points

Summary

Introduction

Growth and yield of crop plants is severely hampered by drought. Water deficit triggers loss of cellular turgor, disruption of water potential gradients, production of reactive oxygen species (ROS), changes in cell volume and membrane integrity, denaturation of proteins, etc. (Lawlor and Cornic, 2002; Wullschleger et al, 2002; Osakabe et al, 2014). As a response to water depletion, the desiccation tolerant species replace the water with accumulation of osmolytes and compounds with ROS scavenging functions (Moore et al, 2005; Peters et al, 2007; Bartels and Hussain, 2011; Jovanovicet al., 2011; Oliver et al, 2011; Yobi et al, 2013; Suguiyama et al, 2014). A general picture of water stress responses in resurrection plants has been proposed, where downregulation of photo-carbon reaction, coupled to respiration allows lowering light stress, while maintaining carbon supply for de novo accumulation of protective compounds to ensure survival of the anhydrobiotes in dry state (Leprince and Hoekstra, 1998; Avelange-Macherel et al, 2006). The increasing of the levels of some enzymes involved in glycolysis during drought indicates a shift between autotrophy and heterotrophy during desiccation in resurrection plants (Griffiths et al, 2014)

Methods

Results

Conclusion