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SYMPOSIA Tuesday - Thursday Page 16 ComBio2017 s Adelaide, South Australia s 2 - 5 October, 2017 SYMPOSIA TUESDAY SYM-01-01 SYM-O1-02 MAKING EPIDERMAL BLADDER CELLS BIGGER: A MOLECULAR MECHANISM FOR HOW PLANTS THE ROLE OF ENDOPOLYPLOIDY IN SALINITY MAINTAIN THEIR CELLULOSE PRODUCING CAPACITY TOLERANCE OF A MODEL HALOPHYTE PLANT DURING SALT STRESS Barkla B.J. and Rhodes T. Kesten C.1, Wallmann A.2, Ford K.3, Heazlewood J.3, Oschkinat H.2 Southern Cross Plant Science, Southern Cross University, Military and Persson S.3 Road, Lismore, NSW 2481. 1Dept of Biology, ETH Zurich, Switzerland. 2Leibniz-Institut für Molekulare Pharmakologie, Germany. 3School of Biosciences, Epidermal bladder cells (EBC) are modified trichomes found on plants University of Melbourne, Australia. in the Aizoaceae and Chenopodaceae, which morphologically resemble small water filled balloons rather than hairs. In Mesembryanthemum Abiotic stress, such as salinity, drought and cold, causes severe yield crystallinum, these cells swell as the plant ages and largest EBC are losses for most plant crop species. Understanding mechanisms for how found on the abaxial epidermis of leaves, as well as on stems and flower to improve plants ability to produce biomass, which largely is constituted buds of salt-treated plants. Here we report that the rapid expansion of by the plant cell wall, during abiotic stress are therefore of upmost the EBC is due to a huge increase in endopolyploidy, DNA replication in importance for agricultural activities. Cellulose is a major component the absence of mitosis, driven by both developmental and environmental of the cell wall, and is synthesized by microtubule-guided cellulose cues. Increasing ploidy levels are observed as leaves expand, and salt- synthase enzymes at the plasma membrane. We have identified two treatment leads to a further increase in endopolyploidy, with ploidy new components of the cellulose synthase complex, which we call levels up to 6X greater estimated for EBC on the flower buds of salt Companions of Cellulose Synthase (CC) proteins. The cytoplasmic treated plants compared to untreated plants. Ploidy increases in these tails of these membrane-spanning proteins bind to microtubules cells are accompanied by large increases in the size of the nucleus and promote their polymerization. This activity supports microtubule with diameters of up to 140 microns routinely measured. Mining of EBC dynamics and cellulose synthase localization at the plasma membrane, transcriptomic data for candidate genes with known roles in cell cycle and renders seedlings less sensitive to salt stress. The seminar will control, nuclear and cell size regulation and cytoskeleton components provide molecular insights into how the CC proteins work to reestablish identified genes with significant changes in salt-treated plants. It has microtubules and cellulose synthesis after salt stress exposure. Hence, been proposed that increased ploidy helps to mitigate stress damage, our findings offer a mechanistic model for how the CC proteins sustain and may contribute to tolerance by increasing the store size for sodium microtubule organization and cellulose synthase localization, and thus sequestration and facilitating higher cellular metabolic activity. This how they aid plant biomass production, during salt stress. study shows that M. crystallinum is an outstanding model for studying endopolyploidization and its physiological role in relationship to both development and environmental stress tolerance. The authors would like to acknowledge financial support from SCPS and an SCU seed grant. SYM-01-03 SYM-01-04 REVEALING THE ROLES OF CALCIUM TRANSPORTERS CO-EXPRESSION MODULES LINK AQUAPORIN GENE IN RESPONSE TO HYPOXIA AND COMBINED HYPOXIA EXPRESSION TO PHYSIOLOGICAL PARAMETERS AND SALINITY STRESS IN ARABIDOPSIS DURING DROUGHT-REHYDRATION IN ARABIDOPSIS Wang F.1, Chen Z.2, Shabala L.1, Colmer T.3 and Shabala S.1 THALIANA 1School of Land and Food, University of Tasmania, Hobart, Tasmania 7001, Australia. 2School of Science and Health, Hawkesbury Institute for the Environment, 3 Scharwies J.D.S., Ramesh S.R. and Tyerman S.D.T. Western Sydney University, Penrith, NSW 2751, Australia. School of Plant Biology and Australian Research Council Centre of Excellence in Plant Energy Institute of Agriculture, The University of Western Australia, Crawley, WA 6009, Australia. Biology, School of Agriculture, Food and Wine, Waite Research 2 Over 17 million km of land is affected by flooding, resulting in substantial yield losses Institute, University of Adelaide, Glen Osmond, 5064 SA, Australia. and jeopardising food security across the globe. Besides the increasingly severe flooding events, the occurrence of the combined salinity and waterlogging stress is also increasing. The crucial role of Ca2+ in response to abiotic and biotic stimuli has been widely recognized The ability of plants to survive stresses like drought determines in plants but still poorly understood within specific cell types in different root zones under their success and ultimately yield in farming systems. Aquaporins hypoxia stress or combined hypoxia and salinity stress. Whole-plant physiological and are molecular channels in plant membranes that provide a gating tissue-specific Ca2+ changes were studied using knock-out Arabidopsis mutants of Ca2+- mechanism for water fluxes and other small molecules. They are ATPase (ACA), Ca2+/proton exchanger (CAX), and respiratory burst oxidase homologue encoded by a family of 35 genes in Arabidopsis thaliana, which show D (RBOHD) in waterlogging treatment or combined stress. In the wild-type (WT) plants, characteristic changes in expression in response to environmental the expressions of ACA8, CAX4, CAX11 and RBOHD were down-regulated by up to 3-fold stresses. Previous research has found connections between aquaporins by hypoxia treatment. Ca2+ accumulation in root tissues was much higher in stelar cells and drought tolerance. This study aims to investigate how changes in the mature zone of aca8, aca11, cax4 and cax11 mutants. In addition, we also show in physiological parameters during drought-rehydration events are that CAX11 plays a key role in maintaining cytosolic Ca2+ homeostasis and/or signalling related to changes in aquaporin gene expression. Drought-rehydration in root cells under hypoxic conditions. Phenotyping experiments found that waterlogging and abscisic acid (ABA) watering experiments were conducted, using stress caused most severe damage to both WT and rbohD compared to salinity stress or 7-week soil-grown Arabidopsis thaliana plants. ABA watering was used combined hypoxia and salinity stress. What’s more, rbohD was more sensitive to salinity, to mimic the stomatal response to drought, without the effect of water waterlogging or combined stress than WT. After pretreated with 48 h of salinity stress, transient hypoxia stress makes rbohD absorb more Na+ and Cl- from elongation and deficit. Physiological parameters, like soil water potential, stomatal mature zones than WT. In most tissues except the elongation zone in rbohD, the H2O2 conductance, relative water content, and leaf ABA, were measured and concentration had decreased after 1 h of hypoxia, but then increased significantly after 24 related to gene expression in the leaves. Aquaporins were clustered into h of hypoxia in each zone and tissue, further suggesting that RBOHD may shape hypoxia- distinct groups according to their expression pattern. A predominant specific Ca2+ signatures via the modulation of apoplastic H2O2 production. In summary, cluster of down-regulated genes showed a good linear correlation with Ca2+ efflux systems especially CAX11 and RBOHD play critical roles in plant adaptive stomatal conductance, while a cluster of up-regulated genes showed to hypoxia stress by shaping the stress-specific Ca2+ signatures. As dependence and a response similar to genes involved in the ABA signaling pathway. reliance of mammalian system on O2 is much stronger than in their plant counterparts, However, no direct regulation by leaf ABA was observed. Compared to acute responses to hypoxia must operate within a timeframe of seconds. O2-regulated drought, ABA watering produced a different pattern of changes in gene ion channels fit this description very well. To further understand the mechanisms by which expression. These results indicate that aquaporin gene expression may plants sense low-oxygen stress, we first summarise and identify several known candidates be regulated in different networks during environmental stress adaption for oxygen sensing in the mammalian literature. We then identify key oxygen sensing and potentially fulfil functions in hydraulic and ABA signal transduction. domains (PAS; GCS; GAF; PHD) in mammalian systems and use the sequences of those oxygen sensing domains to identify the potential plant counterparts in Arabidopsis. Several plasma- and tonoplast based ion channels (such as TPC1) with predicted oxygen sensing ability were identified in plants. ComBio2017 s Adelaide, South Australia s 2 - 5 October, 2017 Page 17 SYMPOSIA TUESDAY SYM-01-05 SYM-O2-01 AN -OMICS APPROACH TO IDENTIFY THE COMMERCIALISING OMEGA-3 EGGS: PRODUCTION REGULATORS OF VEGETATIVE DESICCATION AND BIOAVAILABILITY TOLERANCE IN RESURRECTION PLANTS Carragher J.F.1, Hughes R.J.2, Geier M.S.2, Muhlhausler B.S.1, Phang M.1, Ingle R.A., Lyall R., Proctor J., Schlebusch S. and Illing N. Kartikasari L.R.1, Kanakri K.1 and Gibson R.A.1 Department of Molecular and Cell Biology, University of Cape Town,

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