Perennial ryegrass (Lolium perenne L.) produces high levels of fructans as a mixture of oligosaccharides and polysaccharides with different degrees of polymerization (DP). The present study describes the analysis of the compositional changes in the full spectrum of fructans, fructan distribution between above ground biomass (top) and the roots, and the transcription of candidate genes involved in fructan metabolism during cold acclimation in perennial ryegrass variety “Veyo” and ecotype “Falster” from distinct geographical origins. We observed changes in fructan composition and induction of low-DP fructans, especially DP = 4, in both the top and the roots of “Veyo” and “Falster” in response to low-temperature stress. The accumulation of DP > 50 fructans was only apparent in the top tissues where the Lp1-FFT expression is higher compared to the roots in both “Veyo” and “Falster.” Our results also show the accumulation and depolymerization of fructans with different DP, together with the induction of genes encoding fructosyltransferases and fructan exohydrolases in both “Veyo” and “Falster” during cold acclimation, supporting the hypothesis that fructan synthesis and depolymerization occurring simultaneously. The ecotype “Falster,” adapted to cold climates, increased total fructan content and produced more DP > 7 fructans in the roots than the variety “Veyo,” adapted to warmer climates. This indicates that high-DP fructan accumulation in roots may be an adaptive trait for plant recovery after abiotic stresses.
BackgroundActivation of numerous protective mechanisms during cold acclimation is important for the acquisition of freezing tolerance in perennial ryegrass (Lolium perenne L.). To elucidate the molecular mechanisms of cold acclimation in two genotypes (‘Veyo’ and ‘Falster’) of perennial ryegrass from distinct geographical origins, we performed transcriptome profiling during cold acclimation using RNA-Seq.MethodsWe cold-acclimated plants from both genotypes in controlled conditions for a period of 17 days and isolated Total RNA at various time points for high throughput sequencing using Illumina technology. RNA-seq reads were aligned to genotype specific references to identify transcripts with significant changes in expression during cold acclimation.ResultsThe genes induced were involved in protective mechanisms such as cell response to abiotic stimulus, signal transduction, redox homeostasis, plasma membrane and cell wall modifications, and carbohydrate metabolism in both genotypes. ‘Falster’ genotype, adapted to cold climates, showed a stronger transcriptional differentiation during cold acclimation, and more differentially expressed transcripts related to stress, signal transduction, response to abiotic stimulus, and metabolic processes compared to ‘Veyo’. ‘Falster’ genotype also showed an induction of more transcripts with sequence homology to fructosyltransferase genes (FTs) and a higher fold induction of fructan in response to low-temperature stress. The circadian rhythm network was perturbed in the ‘Veyo’ genotype adapted to warmer climates.ConclusionIn this study, the differentially expressed genes during cold acclimation, potentially involved in numerous protective mechanisms, were identified in two genotypes of perennial ryegrass from distinct geographical origins. The observation that the circadian rhythm network was perturbed in ‘Veyo’ during cold acclimation may point to a low adaptability of ‘Veyo’ to low temperature stresses. This study also revealed the transcriptional mechanisms underlying carbon allocation towards fructan biosynthesis in perennial ryegrass.Electronic supplementary materialThe online version of this article (doi:10.1186/s12870-015-0643-x) contains supplementary material, which is available to authorized users.
In order to characterize the response of selected grasses to water stress, relative water content (RWC) in leaves and quantum efficiency of photosystem 2 (F v /F m ) were measured in Phleum pratense L., P. bertolonii DC. and P. phleoides H. Karst. during 6 d of water stress. The results indicated differential responses to water stress among the three Phleum species with higher water deficit sensitivity of P. pratense and P. bertolonii than that of P. phleoides. The cDNA-amplified fragment length polymorphism (cDNA-AFLP) technique was applied to identify differentially expressed genes responding to water stress in P. pratense. Cloned and sequenced differentially expressed fragments (DEFs) were used for primer design in order to identify orthologous genes in Lolium perenne L. Twelve genes orthologous to P. pratense DEFs were mapped in the L. perenne mapping population VrnA based on a high resolution melting curve analysis (HRM). This study provides genomic information about 29 differentially expressed genes after water stress in P. pratense and reports on the identification and mapping of twelve orthologs in L. perenne.
Perennial ryegrass is an important agricultural crop, however, it is susceptible to winterkill. Freezing injury is caused primarily by ice formation. The LpIRI1 protein has the potential to inhibit ice recrystallization, thus minimize the damage. An association study was conducted using single nucleotide polymorphisms obtained through allele sequencing of the LpIRI1 gene and phenotypic data were collected using two phenotyping platforms in a perennial ryegrass association mapping population of 76 diverse genotypes. Winter survival (FWS) was evaluated under field conditions, while tiller survival (PTS) and electrolyte leakage (EL) at -8 and -12°C were determined under controlled-environment conditions. Proline content (PC) in cold-acclimated plants was measured prior to the freezing test. Significant variation in FWS, PTS, EL and PC was observed among genotypes in our panel. EL and PTS revealed significant negative correlations at -8°C (r s = -0.40) and -12°C (r s = -0.49). PC, however, did not show significant correlations with any of the measured traits, while FWS was correlated (r s = -0.48) with EL at -12°C. The LpIRI1 gene was found to be highly polymorphic with an average SNP frequency of 1 SNP per 16 bp. Association analysis revealed two non-synonymous SNPs being associated with increased EL, both located in the LpIRI1 leucinerich repeat. The results indicate that allelic variation in the LpIRI1 gene plays an important role in the cell membrane integrity of perennial ryegrass during freezing, and can be exploited for developing more freezing tolerant cultivars.
Perennial ryegrass (Lolium perenne L.) is a widely grown species in temperate regions as forage grass as well as for recreational and bioenergy production purposes. Information on perennial ryegrass genetic background facilitates breeding programs by providing an assessment of genetic diversity in exotic material. Genetic diversity of 104 genotypes of perennial ryegrass was evaluated using phenotypic drought traits and amplified fragment length polymorphism (AFLP) data. A high variation was observed for the drought tolerance traits. Chlorophyll fluorescence (F v /F m ) explained 88.8% of the whole variation observed in the collection, while re-growth accounted for 9.1% of all variation. A principal component analysis on the basis of phenotypic drought tolerance traits classified perennial ryegrass collection into three clusters. Three AFLP primer pairs produced a total of 210 fragments, 202 of which were polymorphic among all accessions. The genetic diversity of the collection was high with an average similarity coefficient of 0.46 and the average polymorphic information content of 0.29. The principal component analysis based on AFLP data did not cluster genotypes into any major group. A total of six AFLP fragments, identified as being prevalent in drought tolerant genotypes, together with the high degree of genetic homogeneity found, could provide a choice of selecting genotypes from this perennial ryegrass collection for a drought tolerance breeding program.
Please use the following format when citing the article: Statkevičiūtė G., Kemešytė V., Aleliūnas A., Jonavičienė K., Brazauskas G. 2018 AbstractIn order to evaluate association between sequence polymorphism in candidate genes and phenotypic traits in perennial ryegrass (Lolium perenne L.), mapping population, consisting of 96 genotypes, was assessed for traits related to seed yield with four replications over two years. The traits flag leaf length and width, inflorescence length, spikelet number, seed weight per plant, seed weight per inflorescence, 1000 seed weight and heading date revealed heritability ranging from 0.14 to 0.84 and considerable amount of variation. Marker-trait associations were studied between sequence polymorphism of five candidate genes LpIAA1, LpRUB1, LpBRI1, LpSHOOT1 and LpTB1 with putative function in plant architecture and phenotypic traits. Thirteen marker-trait associations were identified in total. Relation between 3 bp INDEL polymorphism in 3'UTR region of LpBRI1 gene and flag leaf width was confirmed in two consecutive years of field experiment. The possible regulatory role of the identified INDEL is discussed.
In order to identify genes responsible for starch granule initiation during early development of wheat caryopsis, nine winter wheat breeding lines were studied. Two breeding lines, which are the most diverse in A-type granule size (26.85 µm versus 23.65 µm) were chosen for further differential gene expression analysis in developing caryopses at 10 and 15 days post-anthesis (DPA). cDNA-amplified fragment length polymorphism (cDNA-AFLP) analysis resulted in 384 transcript-derived fragments, out of which 18 were identified as being differentially expressed. Six differentially expressed genes, together with the six well-known starch biosynthesis genes, were chosen for semi-quantitative gene expression analysis in developing wheat caryopses at 10 and 15 DPA. This study provides genomic information on 18 genes differentially expressed at early stages of wheat caryopses development and reports on the identification of genes putatively involved in the production of large A-type granules. These genes are targets for further validation on their role in starch granule synthesis control and provide the basis for the development of DNA marker tools in winter wheat breeding for enhanced starch quality.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
334 Leonard St
Brooklyn, NY 11211
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.