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Enhancing wheat field performance and response to abiotic stress with novel growth-regulatory alleles Andy Phillips Peter Hedden Steve Thomas Martin Parry.

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Presentation on theme: "Enhancing wheat field performance and response to abiotic stress with novel growth-regulatory alleles Andy Phillips Peter Hedden Steve Thomas Martin Parry."— Presentation transcript:

1 Enhancing wheat field performance and response to abiotic stress with novel growth-regulatory alleles Andy Phillips Peter Hedden Steve Thomas Martin Parry Ian Prosser Margaret Boulton John Snape Simon Griffiths Nicholas Harberd Nadia Al-Kaff Andrey Korolev Advisory panel Peter Jack, RAGT Seeds Simon Berry, Nickerson- Advanta Mike Gooding, University of Reading John Bingham, farmer and former wheat breeder Mark Dodds, CPB-Twyford

2 Background – there is a need for a greater choice of dwarfing alleles most UK wheat varieties contain Rht-D1b (Rht2) semi-dwarf varieties often require growth retardant (chlormequat) treatment for further growth control altered growing conditions as a result of climate change, reduced N inputs or retardant application may require re- optimisation of dwarfing alleles the wheat germplasm contains a range of largely uncharacterised dwarfing alleles that might be exploited cv. Maris Huntsman Avalon x Cadenza

3 Background – stress responses are sensitive to gibberellin signalling (and vice versa) Growth responses DELLA proteins degradation Biosynthesis deactivation GID1 Low GA, high DELLA (RHT) protects against abiotic stress rhtRht1Rht2Rht3Rht8Rht10Rht12 No NaCl 250 mM NaCl

4 Objectives Determine the effect of Rht semi-dwarfing alleles on tolerance to abiotic stresses (JIC) Characterise the response of the GA-DELLA signalling system to stress (JIC/RRes) Identify genetic loci responsible for variation in wheat stem height through co-localisation of genes encoding components of GA biosynthesis and signalling with height QTLs (RRES) Identify allelic sequence variation in GA-DELLA genes and develop intragenic, allele-specific markers for these loci and validate by crossing into elite germplasm (RRes/JIC). Assess the performance and stress tolerance of the selected alleles (JIC)

5 Approaches – Rht semi-dwarfing alleles and stress tolerance CE, glasshouse, field and polytunnel experiments with Rht NILs Currently plants being grown at two sites (JIC and RRes) and in a polytunnel for monitoring of drought tolerance Traits to be monitored: Emergence and early vigour Times to bolting, anthesis and maturity Architecture Leaf chlorophyll (SPAD meter) Canopy temperature and leaf rolling Yield components Water use efficiency (carbon isotope discrimination) N and C assimilation efficiency and partitioning

6 Approaches: response of the GA-DELLA signalling system to stress GGPPCPP CPS (1) ent-KAURENE KS (1) ent-KAURENOIC ACID KO (1) GA 53 KAO (1) GA 20 GA20ox (4) GA 1 GA3ox (2) GA 8 GA2ox (5) Bio-active Bio-inactive GA 12 GA13ox (0) RHT (1) GID1 (1) GID2 (2) GA-DELLA signalling pathway showing component enzymes/proteins that are potential targets in stress responses. Numbers in parenthesis indicate the number of genes for this component identified in wheat per genome so far. Reference to rice and Brachypodium indicates single copy genes for enzymes early in the pathway and for RHT and GID1, while later biosynthetic and deactivating enzymes are encoded by families of genes.

7 Approaches: response of the GA-DELLA signalling pathway to stress Effects of drought, temperature and salinity on gene expression (qRT-PCR) and on RHT protein stability (antibodies and pRHT::GFP-RHT). Effect of salt on RGA stability in Arabidopsis (Achard et al. Science 311, 91-94, 2006)

8 Approaches: Do GA biosynthesis or signal transduction genes co- localise with height QTLs? Genes are being identified and mapped Parents of mapping populations analysed for polymorphisms using SSCP. Populations: Avalon x Cadenza dh Spark x Realto dh Synthetic x Opata Av Ca Sp Ri Op Syn GA2ox

9 cfd79a0 gwm369wPt wPt barc1915 wmc505b17 2-oxidaseCNFR18 wPt STM635acag23 wmc26425 wPt gwm15551 wPt wPt oxCNFR A GA2ox gene was mapped to chromosome 3AS in Avalon x Cadenza Underlies a height QTL

10 Immediate goals Assess drought tolerance of Rht NILs in the field Set up CE experiments to determine effects of drought and temperature stress on GA signalling and plant development Produce pRHT::GFP-RHT reporter lines Complete mapping of GA signalling genes Establish qRT-PCR for transcript analysis of these genes


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