title: Enhanced expression of Rubisco activase splicing variants differentially affects Rubisco activity during low temperature treatment in Lolium perenne.
abstract: Alternative splicing of the Rubisco activase gene was shown to be a point for optimization of photosynthetic carbon assimilation. It can be expected to be a stress-regulated event that depends on plant freezing tolerance. The aim of the study was to examine the relationships among Rubisco activity, the expression of two Rubisco activase splicing variants and photoacclimation to low temperature. The experiment was performed on two Lolium perenne genotypes with contrasting levels of freezing tolerance. The study investigated the effect of pre-hardening (15°C) and cold acclimation (4°C) on net photosynthesis, photosystem II photochemical activity, Rubisco activity and the expression of two splicing variants of the Rubisco activase gene. The results showed an induction of Rubisco activity at both 15°C and 4°C only in a highly freezing-tolerant genotype. The enhanced Rubisco activity after pre-hardening corresponded to increased expression of the splicing variant representing the large isoform, while the increase in Rubisco activity during cold acclimation was due to the activation of both transcript variants. These boosts in Rubisco activity also corresponded to an activation of non-photochemical mechanism of photoacclimation induced at low temperature exclusively in the highly freezing-tolerant genotype. In conclusion, enhanced expression of Rubisco activase splicing variants caused an increase in Rubisco activity during pre-hardening and cold acclimation in the more freezing-tolerant Lolium perenne genotype. The induction of the transcript variant representing the large isoform may be an important element of increasing the carbon assimilation rate supporting the photochemical mechanism of photosynthetic acclimation to cold.
authors.affiliation: University of Agriculture in Kraków, Faculty of Agriculture and Economics, Department of Plant Physiology, Podłużna 3, 30-239 Kraków, Poland. Electronic address: b.jurczyk@ur.krakow.pl.
authors.forename: Barbara
authors.initials: B
authors.lastname: Jurczyk
authors.affiliation: University of Agriculture in Kraków, Faculty of Agriculture and Economics, Department of Plant Physiology, Podłużna 3, 30-239 Kraków, Poland.
authors.forename: Ewa
authors.initials: E
authors.lastname: Pociecha
authors.affiliation: Institute of Plant Physiology, Polish Academy of Sciences, Niezapominajek 21, 30-239 Kraków, Poland.
authors.forename: Maciej
authors.initials: M
authors.lastname: Grzesiak
authors.affiliation: University of Agriculture in Kraków, Faculty of Agriculture and Economics, Department of Plant Physiology, Podłużna 3, 30-239 Kraków, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Kalita
authors.affiliation: University of Agriculture in Kraków, Faculty of Agriculture and Economics, Department of Plant Physiology, Podłużna 3, 30-239 Kraków, Poland.
authors.forename: Marcin
authors.initials: M
authors.lastname: Rapacz
mesh_terms: D000064:Acclimatization; D002734:Chlorophyll / Q000378:metabolism; D000077194:Chlorophyll A; D003080:Cold Temperature; D005453:Fluorescence; D018506:Gene Expression Regulation, Plant; D008129:Lolium / Q000201:enzymology* / Q000235:genetics* / Q000502:physiology; D010788:Photosynthesis; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D012326:RNA Splicing / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012273:Ribulose-Bisphosphate Carboxylase / Q000235:genetics / Q000378:metabolism
chemical_list: D010940:Plant Proteins; D012333:RNA, Messenger; C054765:rca protein, plant; D002734:Chlorophyll; D012273:Ribulose-Bisphosphate Carboxylase; D000077194:Chlorophyll A
keywords: Alternative splicing; Cold acclimation; Photoacclimation; Pre-hardening; RUBISCO activity