[Seminar] Gene mining in model and halophytic plants: functional identification of stress regulatory genes by random gene transfer and large-scale genetic screens

Seminar

Title: Gene mining in model and halophytic plants: functional identification of stress regulatory genes by random gene transfer and large-scale genetic screens

Speaker: László Szabados

Affiliation: Biological Research Centre, Szeged, Hungary

Host: M. Margarida Oliveira, Plant Functional Genomics Lab

Abstract:

Extreme environmental conditions limit plant growth and impose abiotic stress to plants. Adaptation of plants to suboptimal conditions requires extensive molecular reprogramming leading to major changes in metabolic, proteomic and transcript profiles. Research on Arabidopsis thaliana has identified a number of regulatory genes, which control the pathways linking stress perception and metabolic or developmental responses. Study of a stress sensitive model has however limitations in understanding tolerance to harsh environments. Extremophile plants, such as xerophytes and halophytes can grow in arid regions or on saline soils, which are otherwise lethal to non-adapted species. Such species are valuable sources of tolerance-related genes, which can help to understand the mechanism of adaptation and subsequently improve stress tolerance of crops.

            The Conditional cDNA Overexpression System (COS) was previously developed in our laboratory for functional identification of stress regulatory genes in the model plant Arabidopsis thaliana (Papdi et al., 2008, Rigó et al., 2012). Using the COS system, several novel stress-related Arabidopsis genes were identified, including the Heat Shock Factor A4A, which could enhance salt and oxidative stress tolerance upon overexpression (Pérez-Salamó et al., 2014), the Zinc Finger 3 (ZFP3) factor, regulating abscisic acid (ABA) sensitivity (Joseph et al., 2014) and the ERFVII-type transcription factor RAP2.12 which control responses to low oxygen, oxidative and osmotic stresses (Papdi et al., 2008, 2015). To identify novel stress-related genes in an extremophile plant, the COS system was adapted to Lepidium crassifolium a halophytic relative of the glycophyte Arabidopsis. The modified COS cDNA library was transferred from salt-stressed L. crassifolium plants to Arabidopsis. By screening for salt, osmotic and oxidative stress tolerance through in vitro growth assays and non-destructive chlorophyll fluorescence imaging, 20 Arabidopsis lines were identified with superior performance under restrictive conditions. Several cDNA inserts from L. crassifolium were cloned and confirmed to be responsible for the enhanced tolerance. Examples include cDNAs encoding proteins with high homologies to GDSL-lipase/esterase or acyl CoA-binding protein or proteins without known function, which could confer tolerance to one or several stress conditions (Rigó et al., 2016).

Our results demonstrate, that random gene transfer from stress tolerant to sensitive plant species is a valuable tool to discover novel genes with potential for biotechnological applications.

Acknowledgements

This research was supported by OTKA grant NN-110962, NKFI grant NN-118089 and Bayer CropScience.

References

Joseph MP, Papdi C, Kozma-Bognar L, Nagy I, Lopez-Carbonell M, Rigo G, Koncz C, Szabados L (2014) The Arabidopsis ZINC FINGER PROTEIN3 Interferes with Abscisic Acid and Light Signaling in Seed Germination and Plant Development. Plant Physiol 165: 1203-1220

Papdi C, Abraham E, Joseph MP, Popescu C, Koncz C, Szabados L (2008) Functional identification of Arabidopsis stress regulatory genes using the controlled cDNA overexpression system. Plant Physiol 147: 528-542

Papdi C, Perez-Salamo I, Joseph MP, Giuntoli B, Bogre L, Koncz C, Szabados L (2015) The low oxygen, oxidative and osmotic stress responses synergistically act through the ethylene response factor VII genes RAP2.12, RAP2.2 and RAP2.3. Plant J 82: 772-784

Perez-Salamo I, Papdi C, Rigo G, Zsigmond L, Vilela B, Lumbreras V, Nagy I, Horvath B, Domoki M, Darula Z, Medzihradszky K, Bogre L, Koncz C, Szabados L (2014) The heat shock factor A4A confers salt tolerance and is regulated by oxidative stress and the mitogen-activated protein kinases MPK3 and MPK6. Plant Physiol 165: 319-334

Rigo G, Papdi C, Szabados L (2012) Transformation using controlled cDNA overexpression system. Methods Mol Biol 913: 277-290

Rigo G, Valkai I, Farago D, Kiss E, Van Houdt S, Van de Steene N, Hannah MA, Szabados L (2016) Gene mining in halophytes: functional identification of stress tolerance genes in Lepidium crassifolium. Plant Cell Environ 39: 2074-2084