Barley plants over-expressing the NAC transcription factor gene HvNAC005 show stunting and delay in development combined with early senescence

TY - JOUR

T1 - Barley plants over-expressing the NAC transcription factor gene HvNAC005 show stunting and delay in development combined with early senescence

AU - Christiansen, Michael W.

AU - Matthewman, Colette

AU - Podzimska-Sroka, Dagmara Agata

AU - O'Shea, Charlotte

AU - Lindemose, Søren

AU - Møllegaard, Niels Erik

AU - Holme, Inger Bæksted

AU - Hebelstrup, Kim

AU - Skriver, Karen

AU - Gregersen, Per L.

N1 - © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

PY - 2016/9/1

Y1 - 2016/9/1

N2 - The plant-specific NAC transcription factors have attracted particular attention because of their involvement in stress responses, senescence, and nutrient remobilization. The HvNAC005 gene of barley encodes a protein belonging to subgroup NAC-a6 of the NAC family. This study shows that HvNAC005 is associated with developmental senescence. It was significantly up-regulated following ABA treatment, supported by ABA-responsive elements in its promoter, but it was not up-regulated during dark-induced senescence. The C-termini of proteins closely related to HvNAC005 showed overall high divergence but also contained conserved short motifs. A serine- and leucine-containing central motif was essential for transcriptional activity of the HvNAC005 C-terminus in yeast. Over-expression of HvNAC005 in barley resulted in a strong phenotype with delayed development combined with precocious senescence. The over-expressing plants showed up-regulation of genes involved with secondary metabolism, hormone metabolism, stress, signalling, development, and transport. Up-regulation of senescence markers and hormone metabolism and signalling genes supports a role of HvNAC005 in the cross field of different hormone and signalling pathways. Binding of HvNAC005 to promoter sequences of putative target genes containing the T[G/A]CGT core motif was shown by direct protein-DNA interactions of HvNAC005 with promoters for two of the up-regulated genes. In conclusion, HvNAC005 was shown to be a strong positive regulator of senescence and so is an obvious target for the fine-tuning of gene expression in future attempts to improve nutrient remobilization related to the senescence process in barley.

AB - The plant-specific NAC transcription factors have attracted particular attention because of their involvement in stress responses, senescence, and nutrient remobilization. The HvNAC005 gene of barley encodes a protein belonging to subgroup NAC-a6 of the NAC family. This study shows that HvNAC005 is associated with developmental senescence. It was significantly up-regulated following ABA treatment, supported by ABA-responsive elements in its promoter, but it was not up-regulated during dark-induced senescence. The C-termini of proteins closely related to HvNAC005 showed overall high divergence but also contained conserved short motifs. A serine- and leucine-containing central motif was essential for transcriptional activity of the HvNAC005 C-terminus in yeast. Over-expression of HvNAC005 in barley resulted in a strong phenotype with delayed development combined with precocious senescence. The over-expressing plants showed up-regulation of genes involved with secondary metabolism, hormone metabolism, stress, signalling, development, and transport. Up-regulation of senescence markers and hormone metabolism and signalling genes supports a role of HvNAC005 in the cross field of different hormone and signalling pathways. Binding of HvNAC005 to promoter sequences of putative target genes containing the T[G/A]CGT core motif was shown by direct protein-DNA interactions of HvNAC005 with promoters for two of the up-regulated genes. In conclusion, HvNAC005 was shown to be a strong positive regulator of senescence and so is an obvious target for the fine-tuning of gene expression in future attempts to improve nutrient remobilization related to the senescence process in barley.

U2 - 10.1093/jxb/erw286

DO - 10.1093/jxb/erw286

M3 - Journal article

C2 - 27436280

SN - 0022-0957

VL - 67

SP - 5259

EP - 5273

JO - Journal of Experimental Botany

JF - Journal of Experimental Botany

IS - 17

ER -