The Glycine soja NAC transcription factor GsNAC019 mediates the regulation of plant alkaline tolerance and ABA sensitivity

Abstract

Overexpression of Gshdz4 or GsNAC019 enhanced alkaline tolerance in transgenic Arabidopsis. We proved that Gshdz4 up-regulated both GsNAC019 and GsRD29B but GsNAC019 may repress the GsRD29B expression under alkaline stress. Wild soybean (Glycine soja) has a high tolerance to environmental challenges. It is a model species for dissecting the molecular mechanisms of salt-alkaline stresses. Although many NAC transcription factors play important roles in response to multiple abiotic stresses, such as salt, osmotic and cold, their mode of action in alkaline stress resistance is largely unknown. In our study, we identified a G. soja NAC gene, GsNAC019, which is a homolog of the Arabidopsis AtNAC019 gene. GsNAC019 was highly up-regulated by 50 mM NaHCO treatment in the roots of wild soybean. Further investigation showed that a well-characterized transcription factor, Gshdz4 protein, bound the cis-acting element sequences (CAATA/TA), which are located in the promoter of the AtNAC019/GsNAC019 genes. Overexpression of Gshdz4 positively regulated AtNAC019 expression in transgenic Arabidopsis, implying that AtNAC019/GsNAC019 may be the target genes of Gshdz4. GsNAC019 was demonstrated to be a nuclear-localized protein in onion epidermal cells and possessed transactivation activity in yeast cells. Moreover, overexpression of GsNAC019 in Arabidopsis resulted in enhanced tolerance to alkaline stress at the seedling and mature stages, but reduced ABA sensitivity. The closest Arabidopsis homolog mutant plants of Gshdz4, GsNAC019 and GsRD29B containing athb40, atnac019 and atrd29b were sensitive to alkaline stress. Overexpression or the closest Arabidopsis homolog mutant plants of the GsNAC019 gene in Arabidopsis positively or negatively regulated the expression of stress-related genes, such as AHA2, RD29A/B and KIN1. Moreover, this mutation could phenotypically promoted or compromised plant growth under alkaline stress, implying that GsNAC019 may contribute to alkaline stress tolerance via the ABA signal transduction pathway and regulate expression of the downstream stress-related genes.

Natural variation of an EF-hand Ca2+-binding-protein coding gene confers saline-alkaline tolerance in maize

“…These posttranscriptional mechanisms act together to activate AHA2, then promotes root H + efflux, thereby activating SOS1 Na + /H + antiporter and other adaptive responses 18,25 . Moreover, previous studies have also suggested that the transcript levels of some PM-H + -ATPase increased under stress conditions, e.g., phosphorus deficiency increases the transcript levels of AHA2 and AHA7 26 , iron deficiency increases the expression of AHA2 and AHA7 27 , salt stress upregulates the transcript levels of AHA2 28 . These observations indicate that the transcriptional regulation of PM-H + -ATPase is also important for the regulation of root H + efflux under stress conditions, nevertheless, the mechanism remains largely unknown.…”

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

“…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.…”

Peer Review #1 of "Transcription factors involved in abiotic stress responses in Maize (Zea mays L.) and their roles in enhanced productivity in the post genomics era (v0.1)"

“…In rice for example, overexpression of a NAC TF encoding gene, SNAC1 resulted in increased yields and increased tolerance to drought in transgenic plants (Hu et al, 2006). Overexpression of a Glycine soja NAC TF designated as GsNAC019 in transgenic Arabidopsis resulted in plants that were tolerant to alkaline stress at both the seedling and mature stages although the transgenic plants had reduced sensitivity to Abscisic acid (ABA) (Cao et al, 2017). Similarly, functional analysis of a Pyrus betulifolia NAC TF gene designated as PbeNAC1, revealed that this gene is involved in the regulation of cold and drought stress tolerance (Jin et al, 2017).…”