A novel Glycine soja homeodomain-leucine zipper (HD-Zip) I gene, Gshdz4, positively regulates bicarbonate tolerance and responds to osmotic stress in Arabidopsis

Abstract

BackgroundWild soybean (Glycine soja) is a highly adaptive plant species which can grow well in saline-alkaline soils. In soybean genome, there exist about 140 HD-Zip (Homeodomain-leucine Zipper) genes. HD-Zip transcription factor family is one of the largest plant specific superfamilies and plays important roles in response to abiotic stresses. Although HD-Zip transcription factors have been broadly reported to be involved in plant resistance to abiotic stresses like salt and drought, their roles in response to bicarbonate stress is largely unknown.ResultsFrom our previous transcriptome profile analysis of wild soybean treated by 50 mM NaHCO3, we identified an HD-Zip gene (Gshdz4) which showed high response to the alkaline stress. Our result of qRT-PCR showed that the expression of Gshdz4 was induced by alkaline stress (NaHCO3) in both leaves and roots of wild soybean. Overexpression of Gshdz4 in Arabidopsis resulted in enhanced tolerance to NaHCO3 and KHCO3 during the process of plant growth and development. However, the growths of transgenic and WT plants were not significantly different on the medium with high pH adjusted by KOH, implicating Gshdz4 is only responsible for resisting HCO3− but not high pH. The transgenic plants had less MDA contents but higher POD activities and chlorophyll contents than the WT plants. Moreover, the transcript levels of stress-related genes, such as NADP-ME, H+-Ppase, RD29B and KIN1 were increased with greater extent in the transgenic plants than the wild plants. On the contrary, Gshdz4 overexpression lines were much sensitive to osmotic stress at seed germination and stocking stages compared to the wild plants.ConclusionsWe revealed that the important and special roles of Gshdz4 in enhancing bicarbonate tolerance and responding to osmotic stress. It is the first time to elucidate these novel functions of HD-ZIP transcription factors. All the evidences broaden our understanding of functions of HD-Zip family and provide clues for uncovering the mechanisms of high tolerance of wild soybean to saline-alkaline stresses.Electronic supplementary materialThe online version of this article (doi:10.1186/s12870-016-0872-7) contains supplementary material, which is available to authorized users.

GsSLAH3, a Glycine soja slow type anion channel homolog, positively modulates plant bicarbonate stress tolerance

“…Overexpression of a G. soja ethylene‐responsive factor GsERF6 increased Arabidopsis tolerance to HCO 3 − rather than high pH (Yu et al ). Similarly, another transcription factor Gshdz4 was as well found to regulate bicarbonate stress in Arabidopsis (Cao et al ). In our present work, we showed that GsSLAH3 OX plants had more open and green leaves at germination stage and generated longer roots at seedling stage than WT under KHCO 3 treatment (Fig.…”

Identification of novel interactors and potential phosphorylation substrates of GsSnRK1 from wild soybean (Glycine soja)

“…After washing, the seeds were sowed in soil for germination at 24–26 °C for 20 days in 16‐hr light/8‐hr dark cycles. Every 10 seedlings were treated with dark (6 hr), 50 mM NaHCO 3 (pH 8.5; 12 hr), 200 mM NaCl (12 hr), cold (0 °C for 24 hr), drought (air dry for 4 hr), and ABA (0.1 mM for 24 hr), respectively, according to the described (Cao et al, ). Tobacco ( Nicotiana benthamiana ) and Arabidopsis seeds were directly sowed in soil and grown at 24–26 °C in 16‐hr light/8‐hr dark cycles till for transient infection of agrobacteria and protoplast preparation.…”

“…The whole genome of G. soja has been sequenced and one novel gene ( GmCHX1 ) related with abiotic stresses was identified by comparative genomics (Qi et al, ). Nevertheless, we also reported a dozen of wild soybean genes with resistance to abiotic stresses in plants (Cao et al, , ; Duanmu et al, ; Jia et al, ; Yu et al, , ). However, the functions of SnRK1 kinases (defined as GsSnRK1s) in wild soybean are still largely unknown.…”

Plant transcription factors from the homeodomain‐leucine zipper family I. Role in development and stress responses

“…After the discovery of HD‐Zip proteins in 1991 by Ruberti et al , many HD‐Zip encoding genes had been identified and isolated from A. thaliana and other species such as sunflower , tomato ( Lycopersicum esculentum ) , carrot ( Daucus carota ) , cucumber ( Cucumis sativus ) , cotton ( Gossypium sp) and rice ( O. sativa ) , among others .…”