title: Insertion of a specific fungal 3'-phosphoadenosine-5'-phosphatase motif into a plant homologue improves halotolerance and drought tolerance of plants.
abstract: Soil salinity and drought are among the most serious agricultural and environmental problems of today. Therefore, investigations of plant resistance to abiotic stress have received a lot of attention in recent years. In this study, we identified the complete coding sequence of a 3'-phosphoadenosine-5'-phosphatase protein, ApHal2, from the halotolerant yeast Aureobasidium pullulans. Expression of the ApHAL2 gene in a Saccharomyces cerevisiae hal2 mutant complemented the mutant auxotrophy for methionine, and rescued the growth of the hal2 mutant in media with high NaCl concentrations. A 21-amino-acids-long region of the ApHal2 enzyme was inserted into the Arabidopsis thaliana homologue of Hal2, the SAL1 phosphatase. The inserted sequence included the META motif, which has previously been implicated in increased sodium tolerance of the Hal2 homologue from a related fungal species. Transgenic Arabidopsis plants overexpressing this modified SAL1 (mSAL1) showed improved halotolerance and drought tolerance. In a medium with an elevated salt concentration, mSAL1-expressing plants were twice as likely to have roots in a higher length category in comparison with the wild-type Arabidopsis and with plants overexpressing the native SAL1, and had 5% to 10% larger leaf surface area under moderate and severe salt stress, respectively. Similarly, after moderate drought exposure, the mSAL1-expressing plants showed 14% increased dry weight after revitalisation, with no increase in dry weight of the wild-type plants. With severe drought, plants overexpressing native SAL1 had the worst rehydration success, consistent with the recently proposed role of SAL1 in severe drought. This was not observed for plants expressing mSAL1. Therefore, the presence of this fungal META motif sequence is beneficial under conditions of increased salinity and moderate drought, and shows no drawbacks for plant survival under severe drought. This demonstrates that adaptations of extremotolerant fungi should be considered as a valuable resource for improving stress-tolerance in plant breeding in the future.
authors.affiliation: Department of Biotechnology and Systems Biology, National Institute of Biology, Ljubljana, Slovenia.
authors.forename: Meti Buh
authors.initials: MB
authors.lastname: Gašparič
authors.affiliation: Institute of Biochemistry, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia ; Centre of Excellence for Integrated Approaches in Chemistry and Biology of Proteins (CIPKeBiP), Ljubljana, Slovenia.
authors.forename: Metka
authors.initials: M
authors.lastname: Lenassi
authors.affiliation: Centre of Excellence for Integrated Approaches in Chemistry and Biology of Proteins (CIPKeBiP), Ljubljana, Slovenia ; Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia.
authors.forename: Cene
authors.initials: C
authors.lastname: Gostinčar
authors.affiliation: Department of Biotechnology and Systems Biology, National Institute of Biology, Ljubljana, Slovenia.
authors.forename: Ana
authors.initials: A
authors.lastname: Rotter
authors.affiliation: Institute of Biochemistry, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia.
authors.forename: Ana
authors.initials: A
authors.lastname: Plemenitaš
authors.affiliation: Centre of Excellence for Integrated Approaches in Chemistry and Biology of Proteins (CIPKeBiP), Ljubljana, Slovenia.
authors.forename: Nina
authors.initials: N
authors.lastname: Gunde-Cimerman
authors.affiliation: Department of Biotechnology and Systems Biology, National Institute of Biology, Ljubljana, Slovenia.
authors.forename: Kristina
authors.initials: K
authors.lastname: Gruden
authors.affiliation: Department of Biotechnology and Systems Biology, National Institute of Biology, Ljubljana, Slovenia.
authors.forename: Jana
authors.initials: J
authors.lastname: Zel
mesh_terms: D016960:Agrobacterium tumefaciens / Q000235:genetics / Q000378:metabolism; D020816:Amino Acid Motifs; D017360:Arabidopsis / Q000187:drug effects / Q000201:enzymology / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D055864:Droughts; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D005656:Fungal Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009708:Nucleotidases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D010744:Phosphoric Monoester Hydrolases; D030821:Plants, Genetically Modified; D015202:Protein Engineering; D017434:Protein Structure, Tertiary; D004718:Saccharomycetales / Q000187:drug effects / Q000201:enzymology / Q000235:genetics*; D054712:Salinity; D055049:Salt Tolerance / Q000235:genetics*; D016415:Sequence Alignment; D012965:Sodium Chloride / Q000494:pharmacology; D014170:Transformation, Genetic
chemical_list: D029681:Arabidopsis Proteins; D005656:Fungal Proteins; D012965:Sodium Chloride; D009708:Nucleotidases; D010744:Phosphoric Monoester Hydrolases; C053087:inositol-1,4-bisphosphate 1-phosphatase; C053354:bisphosphoadenylate 3'-nucleotidase