What is PpdH2 doing in winter varieties?

1 .pdf copy (A3) of the original poster presented by the Authors.Temperatures during barley growing season have been on the rise in the Mediterranean basin over the last 40 years. Under these circumstances, winter cereal farmers are exposed to a difficult choice of cultivars for autumn sowing, from spring cultivars in warm areas to strictly winter cultivars. The choice must take into account frost probability for the region. The most common process found in winter cereals to achieve frost tolerance is vernalization, although high frost tolerance can also be attained in cultivars almost devoid of vernalization requirement. We have carried out an experiment with winter barley subjected to insufficient vernalization to test the influence of allelic diversity at genes HvFT1 (VrnH3) and HvFT3 (PpdH2) on development. The experiment used selected plants of the population Esterel x SBCC016, grown in growth chambers. Three F4 lines of each of the four haplotypes determined by HvFT1 and HvFT3, selected with markers, were tested under three different day lengths, 8, 12 and 16h light. The plants were deliberately chosen to be strictly winter types). They were partially vernalized (45 days) before being transferred to the day length chambers, to test the performance of the haplotypes under conditions close to the natural target of the study. The plants showed a large range of duration of development and other phenotypic traits in response to day length, but also between the genetic haplotypes tested. The relationship of the phenotypic development with the expression levels of genes HvFT1, HvFT3, VrnH1 and VrnH2 will be presented and discussed, together with possible agronomic implications. Flowering time is closely related to HvFT1 expression, which seems controlled by a balance between its positive regulator VrnH1 and its well-known repressor VrnH2, but also by an epistatic interaction between VrnH2 and HvFT3, with further implications on tillering.Peer reviewe

Expression analysis of vernalization and day-length response genes in barley (Hordeum vulgare L.) indicates that VRNH2 is a repressor of PPDH2 (HvFT3) under long days

38 Pag., 1 Tabl., 6 Fig.The response to vernalization and the expression of genes associated with responses to vernalization (VRNH1, VRNH2, and VRNH3) and photoperiod (PPDH1 and PPDH2) were analysed in four barley (Hordeum vulgare L.) lines: ‘Alexis’ (spring), ‘Plaisant’ (winter), SBCC058, and SBCC106 (Spanish inbred lines), grown under conditions of vernalization and short days (VSD) or no vernalization and long days (NVLD). The four genotypes differ in VRNH1. Their growth habits and responses to vernalization correlated with the level of expression of VRNH1 and the length of intron 1. ‘Alexis’ and ‘Plaisant’ behaved as expected. SBCC058 and SBCC106 showed an intermediate growth habit and flowered relatively late in the absence of vernalization. VRNH1 expression was induced by cold for all genotypes. Under VSD, VRNH1 expression was detected in the SBCC genotypes later than in ‘Alexis’ but earlier than in ‘Plaisant’. VRNH2 was repressed under short days while VRNH1 expression increased in parallel. VRNH3 was detected only in ‘Alexis’ under NVLD, whereas it was not expressed in plants with the active allele of VRNH2 (SBCC058 and ‘Plaisant’). Under VSD, PPDH2 was expressed in ‘Alexis’, SBCC058, and SBCC106, but it was only expressed weakly in ‘Alexis’ under NVLD. Further analysis of PPDH2 expression in two barley doubled haploid populations revealed that, under long days, HvFT3 and VRNH2 expression levels were related inversely. The timing of VRNH2 expression under a long photoperiod suggests that this gene might be involved in repression of PPDH2 and, indirectly, in the regulation of flowering time through an interaction with the day-length pathway.This study was funded by grants AGL2007-63625 and HH2008-0013 from the Spanish Ministry of Science and Technology and by the European Regional Development Fund. Germplasm from the SBCC is maintained with funding from project RFP2004-00015-00-00. MCC was supported by an I3P Predoctoral Fellowship from CSIC.Peer reviewe

Perspectives on Low Temperature Tolerance and Vernalization Sensitivity in Barley: Prospects for Facultative Growth Habit

15 Pags.- 5 Figs.- 3 TAbls.- Supp. Mat. Copyright Owner, the Authors. Under LicenceCC BY 4.0.One option to achieving greater resiliency for barley production in the face of climate change is to explore the potential of winter and facultative growth habits: for both types, low temperature tolerance (LTT) and vernalization sensitivity are key traits. Sensitivity to short-day photoperiod is a desirable attribute for facultative types. In order to broaden our understanding of the genetics of these phenotypes, we mapped quantitative trait loci (QTLs) and identified candidate genes using a genome-wide association studies (GWAS) panel composed of 882 barley accessions that was genotyped with the Illumina 9K single-nucleotide polymorphism (SNP) chip. Fifteen loci including 5 known and 10 novel QTL/genes were identified for LTT—assessed as winter survival in 10 field tests and mapped using a GWAS meta-analysis. FR-H1, FR-H2, and FR-H3 were major drivers of LTT, and candidate genes were identified for FR-H3. The principal determinants of vernalization sensitivity were VRN-H1, VRN-H2, and PPD-H1. VRN-H2 deletions conferred insensitive or intermediate sensitivity to vernalization. A subset of accessions with maximum LTT were identified as a resource for allele mining and further characterization. Facultative types comprised a small portion of the GWAS panel but may be useful for developing germplasm with this growth habit.Support was provided by the USDA-NIFA TCAP Project no. 2011-68002-30029.Peer reviewe

Adaptation of barley to mild winters: A role for PPDH2

39 Pags., 3 Tabls., 4 Figs. The definitive version is available at: http://www.biomedcentral.com/bmcplantbiolBackground Understanding the adaptation of cereals to environmental conditions is one of the key areas in which plant science can contribute to tackling challenges presented by climate change. Temperature and day length are the main environmental regulators of flowering and drivers of adaptation in temperate cereals. The major genes that control flowering time in barley in response to environmental cues are VRNH1, VRNH2, VRNH3, PPDH1, and PPDH2 (candidate gene HvFT3). These genes from the vernalization and photoperiod pathways show complex interactions to promote flowering that are still not understood fully. In particular, PPDH2 function is assumed to be limited to the ability of a short photoperiod to promote flowering. Evidence from the fields of biodiversity, ecogeography, agronomy, and molecular genetics was combined to obtain a more complete overview of the potential role of PPDH2 in environmental adaptation in barley. Results The dominant PPDH2 allele is represented widely in spring barley cultivars but is found only occasionally in modern winter cultivars that have strong vernalization requirements. However, old landraces from the Iberian Peninsula, which also have a vernalization requirement, possess this allele at a much higher frequency than modern winter barley cultivars. Under field conditions in which the vernalization requirement of winter cultivars is not satisfied, the dominant PPDH2 allele promotes flowering, even under increasing photoperiods above 12 h. This hypothesis was supported by expression analysis of vernalization-responsive genotypes. When the dominant allele of PPDH2 was expressed, this was associated with enhanced levels of VRNH1 and VRNH3 expression. Expression of these two genes is needed for the induction of flowering. Therefore, both in the field and under controlled conditions, PPDH2 has an effect of promotion of flowering. Conclusions The dominant, ancestral, allele of PPDH2 is prevalent in southern European barley germplasm. The presence of the dominant allele is associated with early expression of VRNH1 and early flowering. We propose that PPDH2 promotes flowering of winter cultivars under all non-inductive conditions, i.e. under short days or long days in plants that have not satisfied their vernalization requirement. This mechanism is indicated to be a component of an adaptation syndrome of barley to Mediterranean conditions.This study was funded by grants AGL2007-63625, AGL2010-21929, and HH2008-0013 from the Spanish Ministry of Science and Technology, by the European Regional Development Fund, and by the Hungarian Scientific Research Fund (OTKA NK72913). Germplasm from the SBCC is maintained with funding from projects RFP2004-00015-00-00 and RFP2009-00005-00-00. MCC was supported by an I3P Predoctoral Fellowship from CSIC.Peer reviewe

Responses of Barley to High Ambient Temperature Are Modulated by Vernalization

16 pags.- 6 Figs.- 3 Tabls. © 2022 Ochagavía, Kiss, Karsai, Casas and Igartua. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY).Ambient temperatures are increasing due to climate change. Cereal crops development and production will be affected consequently. Flowering time is a key factor for adaptation of small grain cereals and, therefore, exploring developmental responses of barley to rising temperatures is required. In this work, we studied phasic growth, and inflorescence traits related to yield, in eight near isogenic lines of barley (Hordeum vulgare L.) differing at the VRN-H1, VRN-H2 and PPD-H1 genes, representing different growth habits. The lines were grown in contrasting vernalization treatments, under two temperature regimes (18 and 25°C), in long days. Lines with recessive ppd-H1 presented delayed development compared to lines with the sensitive PPD-H1 allele, across the two growth phases considered. High temperature delayed flowering in all unvernalized plants, and in vernalized spring barleys carrying the insensitive ppd-H1 allele, whilst it accelerated flowering in spring barleys with the sensitive PPD-H1 allele. This finding evidenced an interaction between PPD-H1, temperature and vernalization. At the high temperature, PPD-H1 lines in spring backgrounds (VRN-H1-7) yielded more, whereas lines with ppd-H1 were best in vrn-H1 background. Our study revealed new information that will support breeding high-yielding cultivars with specific combinations of major adaptation genes tailored to future climatic conditions.Funding of this research was provided was provided by project AGL2016-80967-R (Agencia Estatal de Investigación, Ministry of Economy and Competitiveness), project PID2019-111621RB-I00 (Agencia Estatal de Investigación), grants A08_17R and A08_20R (Government of Aragón), and project GINOP-2.3.2-15-2016-00029 (Economic Development Programs of the Hungarian Ministry of Finance). HO was supported by a Juan de la Cierva-Formación fellowship, granted by the Spanish Ministry of Science and Innovation (FJC2018-037885-I).Peer reviewe

Raw data of barley experiment subjected to different vernalization and temperature treatments [Dataset]

[EN] This Excel file contains the raw data of the experiment reported in the article “Responses of Barley to High Ambient Temperature Are Modulated by Vernalization”, published in Frontiers in Plant Science, and referenced as Supplementary Table 7. Data are phenological development variables and yield-related variables for eight genotypes of barley grown in growth chambers, under four treatments combining presence/absence of vernalization and normal/high temperatures == [ES] Archivo excel con los datos de un experimento incluido en la publicación Ochagavía et al., en Frontiers in Plant Science. La primera hoja contiene la explicación de los datos, recogidos en la segunda hoja del archivo.This dataset is covered by a Creative Commons Licence Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0).Raw data (Supplementary Table 7) of article by Ochagavía et al., published in Frontiers in Plant Science.Funding of this research was provided was provided by project AGL2016-80967-R (Agencia Estatal de Investigación, Ministry of Economy and Competitiveness), project PID2019- 111621RB-I00 (Agencia Estatal de Investigación), grants A08_17R and A08_20R (Government of Aragón), and project GINOP-2.3.2-15-2016-00029 (Economic Development Programs of the Hungarian Ministry of Finance).Peer reviewe

Barley adaptation. Lessons learned from landraces will help to cope with climate change

27 Pags., with Figs. y Tabls.Adaptation of crops to temperate climates depends to a large extent on plants having the appropriate combination of genes to respond to environmental cues. Global warming poses new challenges to plant breeding. In many places, current cultivars will no longer be suited for cultivation. We present several findings on barley adaptation to Mediterranean climates, which resulted from the study of adaptations presented by local landraces. Winter barley is widely grown in the Mediterranean region. We found that local winter landraces have some degree of vernalization requirement, tuned to respond to the winter temperatures typical for each region. Our results demonstrate that the allelic series of the main vernalization gene, VrnH1, is essential to determine the length of the cold period needed to promote flowering in barley. The presence of photoperiod gene HvFT3 in most Mediterranean landraces is presented as a safety mechanism to promote flowering, which comes into play at least when vernalization conditions are not optimum (rather often in some areas). This mechanism is coordinated with the vernalization pathway through repression by VrnH2. A latitudinal pattern of distribution of HvFT1 in Spanish barleys suggests a role in adaptation. This gene integrates the photoperiod and vernalization pathways in barley, and seems to present an allelic series of at least five functionally different alleles. We present evidences from several independent sets of materials that demonstrate the effect of three of these alelles, in accordance with the latitudinal distribution observed. A combination of these three mechanisms optimizes the growth cycle of Mediterranean landraces. These mechanisms have a wider interest in a climate change scenario, as temperatures in most of Europe will increase, and may become beneficial in higher latitudes. Cultivars with new combinations of vernalization, photoperiod and frost tolerance alleles will have to be bred for the upcoming conditions.Funded by Spanish Ministries of Economy and Competitiveness (former Science and Innovation) and Agriculture.Peer reviewe

Fine-tuning of the flowering time control in winter barley: the importance of HvOS2 and HvVRN2 in non-inductive conditions

[Background] In winter barley plants, vernalization and photoperiod cues have to be integrated to promote flowering. Plant development and expression of different flowering promoter (HvVRN1, HvCO2, PPD-H1, HvFT1, HvFT3) and repressor (HvVRN2, HvCO9 and HvOS2) genes were evaluated in two winter barley varieties under: (1) natural increasing photoperiod, without vernalization, and (2) under short day conditions in three insufficient vernalization treatments. These challenging conditions were chosen to capture non-optimal and natural responses, representative of those experienced in the Mediterranean area.[Results] In absence of vernalization and under increasing photoperiods, HvVRN2 expression increased with day-length, mainly between 12 and 13 h photoperiods in our latitudes. The flowering promoter gene in short days, HvFT3, was only expressed after receiving induction of cold or plant age, which was associated with low transcript levels of HvVRN2 and HvOS2. Under the sub-optimal conditions here described, great differences in development were found between the two winter barley varieties used in the study. Delayed development in ‘Barberousse’ was associated with increased expression levels of HvOS2. Novel variation for HvCO9 and HvOS2 is reported and might explain such differences.[Conclusions] The balance between the expression of flowering promoters and repressor genes regulates the promotion towards flowering or the maintenance of the vegetative state. HvOS2, an ortholog of FLC, appears as a strong candidate to mediate in the vernalization response of barley. Natural variation found would help to exploit the plasticity in development to obtain better-adapted varieties for current and future climate conditions.Study financially supported by the Spanish Ministry of Economy, Industry and Competitiveness (Projects AGL2013–48756-R, including a scholarship granted to AM, and AGL2016–80967-R). The funding body did not play any role in the design of the study, collection, analysis, interpretation of the data or in writing the manuscript. We acknowledge support of the publication fee by the CSIC Open Access Publication Support Initiative through its Unit of Information Resources for Research (URICI)

Validation of the VRN-H2/VRN-H1 epistatic model in barley reveals that intron length variation in VRN-H1 may account for a continuum of vernalization sensitivity

The epistatic interaction of alleles at the VRN-H1 and VRN-H2 loci determines vernalization sensitivity in barley. To validate the current molecular model for the two-locus epistasis, we crossed homozygous vernalization-insensitive plants harboring a predicted >winter type> allele at either VRN-H1 (Dicktoo) or VRN-H2 (Oregon Wolfe Barley Dominant), or at both VRN-H (Calicuchima-sib) loci and measured the flowering time of unvernalized F2 progeny under long-day photoperiod. We assessed whether the spring growth habit of Calicuchima-sib is an exception to the two-locus epistatic model or contains novel >spring> alleles at VRN-H1 (HvBM5A) and/or VRN-H2 (ZCCT-H) by determining allele sequence variants at these loci and their effects relative to growth habit. We found that (a) progeny with predicted >winter type> alleles at both VRN-H1 and VRN-H2 alleles exhibited an extremely delayed flowering (i.e. vernalization-sensitive) phenotype in two out of the three F2 populations, (b) sequence flanking the vernalization critical region of HvBM5A intron 1 likely influences degree of vernalization sensitivity, (c) a winter habit is retained when ZCCT-Ha has been deleted, and (d) the ZCCT-H genes have higher levels of allelic polymorphism than other winterhardiness regulatory genes. Our results validate the model explaining the epistatic interaction of VRN-H2 and VRN-H1 under long-day conditions, demonstrate recovery of vernalization-sensitive progeny from crosses of vernalization-insensitive genotypes, show that intron length variation in VRN-H1 may account for a continuum of vernalization sensitivity, and provide molecular markers that are accurate predictors of >winter vs spring type> alleles at the VRN-H loci.This work was supported by the National Science Foundation Plant Genome Research Program (DBI 0110124) and the United States Barley Genome Project.Peer Reviewe

Vrn-H1 and Vrn-H2 allelic diversity in barley may explain specific adaptation to the Mediterranean environments

5 Pag., 3 Fig, 1 Tabl. In Molina Cano J.L. (ed.), Christou P. (ed.), Graner A. (ed.), Hammer K. (ed.), Jouve N. (ed.), Keller B. (ed.), Lasa J.M. (ed.), Powell W. (ed.), Royo C. (ed.), Shewry P. (ed.), Stanca A.M. (ed.) . Cereal science and technology for feeding ten billion people: genomics era and beyond . Zaragoza : CIHEAM-IAMZ / IRTA, 2008. p. 105-109 : 17 réf., 1 tabl., 2 graph. (Options Méditerranéennes : Série A. Séminaires Méditerranéens ; n. 81). Meeting of the Eucarpia Cereal Section, 2006/11/13-17, Lleida (Spain)In this study, allelic diversity for those genes was evaluated in a wide sample of genotypes, winter and spring, 2 and 6-row barleys, mainly from the Western Mediterranean region. It included 159 landraces from the Spanish Barley Core Collection (SBCC, Igartua et al ., 1998) and a set of 80 accessions (reference cultivars) mainly from other European countries. Specific alleles for VRN-H1 were found in the Iberian Peninsula, in a higher frequency than that seen in other materials. Allelic diversity matches with flowering time phenotypic responses across several series of field trials and controlled conditions experiments. The phenotypic differences apparently may entail adaptive responses. These results led us to initiate a marker-assisted selection program to introduce the vernalization genes of a Spanish accession into the French winter cultivar Plaisant.This work was supported by the Spanish Ministry of Education and Research (Projects AGL2001- 2289, AGL2004-05311), INIA (Project RTA03-028-C4) and by the European Regional Development Fund.Peer reviewe