Soybean NAC transcription factors promote abiotic stress tolerance and lateral root formation in transgenic plants

Abstract

). † These authors contributed equally to this work. SUMMARYNAC transcription factors play important roles in plant growth, development and stress responses. Previously, we identified multiple NAC genes in soybean (Glycine max). Here, we identify the roles of two genes, GmNAC11 and GmNAC20, in stress responses and other processes. The two genes were differentially induced by multiple abiotic stresses and plant hormones, and their transcripts were abundant in roots and cotyledons. Both genes encoded proteins that localized to the nucleus and bound to the core DNA sequence CGT[G/A]. In the protoplast assay system, GmNAC11 acts as a transcriptional activator, whereas GmNAC20 functions as a mild repressor; however, the C-terminal end of GmANC20 has transcriptional activation activity. Overexpression of GmNAC20 enhances salt and freezing tolerance in transgenic Arabidopsis plants; however, GmNAC11 over-expression only improves salt tolerance. Over-expression of GmNAC20 also promotes lateral root formation. GmNAC20 may regulate stress tolerance through activation of the DREB/CBF-COR pathway, and may control lateral root development by altering auxin signaling-related genes. GmNAC11 probably regulates DREB1A and other stress-related genes. The roles of the two GmNAC genes in stress tolerance were further analyzed in soybean transgenic hairy roots. These results provide a basis for genetic manipulation to improve the agronomic traits of important crops.

Physiological adaptive mechanisms of plants grown in saline soil and implications for sustainable saline agriculture in coastal zone

“…Due to the complexity of functional genes in response to salt stress, conventional breeding program is relatively hard to be executed effectively (Flowers 2004;Shabala and Cuin 2008;Shao et al 2009Shao et al , 2010. Although many studies have announced that salt tolerance was enhanced in transgenic plants (Begcy et al 2011;Hao et al 2011;Jacobs et al 2011;Rahnama et al 2011;Wei et al 2011), the results are obtained under abnormal growth condition and not tested in the field. Stress resistance training and exogenous application of growth and osmotic regulators have been demonstrated to ameliorate plant salt stress (Amzallag et al 1990;Umezawa et al 2000;Chattopadhayay et al 2002;Demiral and Turkan 2006;Chen et al 2007;Kaya et al 2007;Wahid et al 2007;Athar et al 2008;Zheng et al 2008;Reezi et al 2009;Chang et al 2010;Cimrin et al 2010;Khan et al 2010;Akram and Ashraf 2011;Fan et al 2011;Idrees et al 2011;Lin et al 2011;Nazar et al 2011;Sakr et al 2012).…”

Genome-wide analysis and expression patterns of the NAC transcription factor family in Medicago truncatula

“…NAC proteins are involved in responses to viral infections during plant vegetative development. In soybean, GmNAC11 and GmNAC20 are involved in responses to low temperature, and overexpression of these two genes enhanced low temperature tolerance (Hao et al 2011). …”

The Arabidopsis NAC Transcription Factor ANAC096 Cooperates with bZIP-Type Transcription Factors in Dehydration and Osmotic Stress Responses

“…They play pivotal roles in plant development, senescence, auxin responses, and biotic stress responses (Aida et al, 1997;Olsen et al, 2005aOlsen et al, , 2005bLu et al, 2007;Kim et al, 2009;Jensen et al, 2010;Hao et al, 2011;Nakashima et al, 2012;Puranik et al, 2012;Sun et al, 2012). The Arabidopsis thaliana genome encodes more than 100 NAC domain-containing genes, which can be divided into 10 major groups based on phylogenetic analysis (Jensen et al, 2010).…”