Investigation of the role of strigolactones in barley in response to drought
Plant Cultivation, Plant Nutrition, Agricultural Technology
Final Report Abstract
Strigolactones (SLs) are described as a class of plant hormones that promotes symbiotic interactions in the rhizosphere and that regulates plant architecture and organ development. Preliminary data indicate that the SL signaling mutant hvd14.d is hypersensitive to drought and insensitive to ABA treatment. The overall goal of the proposed project is to further dissect the ABA-SL interaction to reveal their role in the crop species barley in response to drought stress. Allele mining for HvD14 (HORVU4Hr1G070070) using the SNP Browser tool available in the Bridge Web Portal database reveals that both the coding and the promoter sequence of HvD14 are highly conserved among barley genotypes. To further elucidate the role of SLs in response to drought, mutants with defects in SL biosynthesis (HvD10, HvD17, HvD27) and signaling (HvD14 and HvD53) using TILLING (cv. Sebastian), and mutants with defects in SL biosynthesis (HvD10, HvD17, HvD27, HvMAX1) and signaling (HvD14) using CRISPR/Cas9 targeted mutagenesis (cv. Golden Promise), were developed and used for further experiments. In addition, a max1 mutant with defects in four of the five MAX1 orthologs (max1-qko) from the Brewer lab at the University of Adelaide was included into the experiments. Exposed to drought, TILLING biosynthesis mutants (genes: HvD10, HvD17, HvD27) were hypersensitive to drought stress and showed a similar phenotype as the previously described hvd14.d mutant. However, plants with a mutation in the SL repressor HvD53 produced fewer tillers under control conditions but were more tolerant to drought stress than the parent cultivar Sebastian. Also CRISPR mutants in genes HvD10, HvD17, HvD27 and HvD14 were more sensitive to drought, when compared to Golden Promise. Interestingly, Hhvdmax-1 mutant that have a defect in one of the five MAX1-orthologs, did not show an altered phenotype under control conditions or altered sensitivity to drought stress. Morphological and structural data strongly confirmed these, indicating that mutations in the core SL biosynthesis pathway impairs barley's response to drought stress. Mutation in genes encoding enzymes related to SL diversification does not significantly affect the response of barley to drought stress, indicating that the products of MAX1 activity are not involved in the coordination of barley's response to drought stress. Global gene expression profiles (RNA-seq) for each SL-mutant and Golden Promise were analysed under control and stress conditions to identify differential gene expression (DEG) in response to drought. Based on meta-analyses of all data from experiments with the mutant collections SL-dependent and independent genes involved in the response of barley to drought stress were selected. These will be used for further analysis to identify transcription factors that may regulate this response. Data on the hormone measurements, performed in the IPK Molecular Plant Nutrition research group, are still being processed.
Publications
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Barley strigolactone signalling mutant hvd14.d reveals the role of strigolactones in abscisic acid‐dependent response to drought. Plant, Cell & Environment, 43(9), 2239-2253.
Marzec, Marek; Daszkowska‐Golec, Agata; Collin, Anna; Melzer, Michael; Eggert, Kai & Szarejko, Iwona
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Multi-omics insights into the positive role of strigolactone perception in barley drought response. BMC Plant Biology, 23(1).
Daszkowska-Golec, Agata; Mehta, Devang; Uhrig, R. Glen; Brąszewska, Agnieszka; Novak, Ondrej; Fontana, Irene M.; Melzer, Michael; Płociniczak, Tomasz & Marzec, Marek
