Expression pattern of the psbO gene and its involvement in acclimation of the photosynthetic apparatus during abiotic stresses in Festuca arundinacea and F. pratensis

Izabela Pawłowicz,Marcin Rapacz,Arkadiusz Kosmala

doi:10.1007/s11738-012-0992-0

Abstract

PsbO, the manganese-stabilizing protein, plays a crucial role in oxygen-evolving complex functioning and stabilization, by maintaining optimal manganese, calcium and chloride concentrations at the active state of PSII. In this paper we present a study focused on recognizing the relationship between psbO gene activity and acclimation of the photosynthetic apparatus under abiotic stresses in the grasses Festuca arundinacea and F. pratensis. PsbO expression was compared between two distinct genotypes within each species which differed in their levels of stress tolerance (drought and frost, respectively) during drought treatment (F. arundinacea) and cold acclimation (F. pratensis). The research involved: (1) the analyses of psbO gene expression profiles using real-time PCR, and (2) the analyses of PsbO protein accumulation profiles using protein gel blot hybridization. The results indicate that PsbO plays a protective function with respect to the photosynthetic apparatus during abiotic stresses. In cold-treated F. pratensis plants the accumulation of PsbO seems to be responsible for differences in the PSII photochemical efficiency. Higher stability of PSII during drought, observed in the high-drought tolerant F. arundinacea genotype, is not associated with PsbO accumulation, although the degradation of this protein affects destabilization of the oxygen-evolving complex in drought.

Highlights

Abiotic stresses, such as drought and frost, are the main factors that affect plant production worldwide
50 mg of leaf fresh weight were ground in liquid nitrogen and The initial level of Relative water content (RWC) did not differ between homogenized in extraction buffer containing 50 mM Tris– high-drought tolerant (HDT) and low-drought tolerant (LDT) genotypes (Fig. 1A)
The aim was to discover if distinct abiotic stresses: drought in F. arundinacea and low temperature in F. pratensis, may affect psbO gene expression, and to see if the patterns of these changes are connected with the differences in stress tolerance level observed between distinct genotypes of Fa and Fp

Summary

Introduction

Abiotic stresses, such as drought and frost, are the main factors that affect plant production worldwide. PsbO, called the manganese-stabilizing protein (MSP), was first found in spinach chloroplasts (Kuwabara and Murata 1979) and is highly conserved in higher plants (Bricker and Burnap 2005). It is a nucleus-encoded protein whose precursor is synthesized in the cytoplasm and transported to the chloroplasts, and localized at the lumenal side of PSII (Hashimoto et al 1997). PsbO may participate in the protection of PSII against photodamage, since recent reports indicate that PSII photoinhibition could be initiated exactly at the Mn-cluster stabilized by PsbO (Sarvikas et al 2006)

Methods

Results

Conclusion