Water Deficit Affects Primary Metabolism Differently in Two Lolium multiflorum/Festuca arundinacea Introgression Forms with a Distinct Capacity for Photosynthesis and Membrane Regeneration.

Dawid Perlikowski,Łukasz Marczak,Mariusz Czyżniejewski,Adam Augustyniak,Arkadiusz Kosmala

doi:10.3389/fpls.2016.01063

Abstract

Understanding how plants respond to drought at different levels of cell metabolism is an important aspect of research on the mechanisms involved in stress tolerance. Furthermore, a dissection of drought tolerance into its crucial components by the use of plant introgression forms facilitates to analyze this trait more deeply. The important components of plant drought tolerance are the capacity for photosynthesis under drought conditions, and the ability of cellular membrane regeneration after stress cessation. Two closely related introgression forms of Lolium multiflorum/Festuca arundinacea, differing in the level of photosynthetic capacity during stress, and in the ability to regenerate their cellular membranes after stress cessation, were used as forage grass models in a primary metabolome profiling and in an evaluation of chloroplast 1,6-bisphosphate aldolase accumulation level and activity, during 11 days of water deficit, followed by 10 days of rehydration. It was revealed here that the introgression form, characterized by the ability to regenerate membranes after rehydration, contained higher amounts of proline, melibiose, galactaric acid, myo-inositol and myo-inositol-1-phosphate involved in osmoprotection and stress signaling under drought. Moreover, during the rehydration period, this form also maintained elevated accumulation levels of most the primary metabolites, analyzed here. The other introgression form, characterized by the higher capacity for photosynthesis, revealed a higher accumulation level and activity of chloroplast aldolase under drought conditions, and higher accumulation levels of most photosynthetic products during control and drought periods. The potential impact of the observed metabolic alterations on cellular membrane recovery after stress cessation, and on a photosynthetic capacity under drought conditions in grasses, are discussed.

Highlights

The sedentary life style of plants exposes them to many unfavorable environmental conditions, limiting their growth and development
The rapid amplification of cDNA ends (RACE) analysis performed on total RNA extracted from the two introgression forms allowed the identification of two plastid Fructose-1 (pFBA) mRNA sequences in each form (Supplementary Figure S1)
The results obtained in this study clearly indicate that accumulation and activity levels of pFBA can influence the capacity of photosynthesis in the L. multiflorum/F. arundinacea introgression forms, due to the efficiency of the Calvin cycle

Summary

Introduction

The sedentary life style of plants exposes them to many unfavorable environmental conditions, limiting their growth and development. The rate of photosynthesis could be limited by a carboxylation of Rubisco and by a ribulose-1,5-bisphosphate regeneration capacity, which could be reduced mainly by a decreased accumulation of plastid fructose1,6-bisphosphatase (Kossmann et al, 1995), an inhibition of sedoheptulose-1,7-bisphosphatase (Harrison et al, 1998) and a reduced accumulation of chloroplast fructose-1,6-bisphosphate aldolase (pFBA; Haake et al, 1998, 1999; Uematsu et al, 2012) As it was demonstrated earlier, alterations in photosynthetic carbon metabolism in response to drought could be strongly associated with accumulation levels of several classes of primary metabolites, mostly plant hormones, osmoprotectants and ROS scavenging particles which are crucial to develop drought tolerance (Chandler and Robertson, 1994). These compounds could function as chaperone-like molecules stabilizing membranes and maintaining the activity and stability of the enzymes crucial for a proper functioning of cell metabolism (Xoconostle-Cazares et al, 2010)

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Discussion

Conclusion