6 Conclusion
NAC proteins are among the families of plant-specific TFs with the most number
of members. This is reflected in the variety of processes that they regulate, including
development, stress tolerance and wood formation. Most NAC proteins have a
modular organization formed by a conserved N-terminal DNA-binding domain
and by a C-terminal domain that is highly variable and plays a role in transcriptional
regulation and in protein–protein interaction. These TFs are able to be regulated by
alternative splicing, miRNA and post-translational modifications such as phosphorylation or ubiquitination; they can also interact with many different types of proteins.
Several NAC proteins associated with vascular development and stress responses
have been conserved along plant evolution, suggesting a prominent role of these
proteins in their survival and colonization of land habitats. Further, the bulk of the
tree biomass that is potentially useful for diverse purposes is based on the trees’ trunk
volume. Because NAC transcription factors are key regulators of the regulatory
network controlling wood formation, this raises the possibility of their use in
biotechnological processes to modify the quantity and potential quality of the
arboreal biomass.
Acknowledgements Research work in the authors’s laboratory was supported by grants from
“Ministerio de Economía y Competitividad” (BIO2015–69285-R) and the European Union
(FP7-KBBE-289841).
References
Aida M, Tetsuya I, Fukaki H, Fujisawa H, Tasaka M (1997) Genes involved in organ separation
in Arabidopsis: an analysis of the cup-shaped cotyledon mutant. Plant Cell 9:841–857
Aida M, Ishida T, Tasaka M (1999) Shoot apical meristem and cotyledon formation during
Arabidopsis embryogenesis: interaction among the CUP-SHAPED COTYLEDON and
SHOOT MERISTEMLESS genes. Development 126:1563–1570
Axtell MJ, Snyder JA, Bartel DP (2007) Common functions for diverse small RNAs of land plants.
Plant Cell 19:1750–1769
Barah P, Naika MBN, Jayavelu ND, Sowdhamini R, Shameer K, Bones AM (2016) Transcriptional
regulatory networks in Arabidopsis thaliana during single and combined stresses. Nucleic Acids
Res 44:3147–3164
Bedon F, Bomal C, Caron S, Levasseur C, Boyle B, Mansfield SD, Schmidt A et al (2010)
Subgroup 4R2R3-MYBs in conifer trees: gene family expansion and contribution to the
isoprenoid- and flavonoid-oriented responses. J Exp Bot 61:3847–3864
Bennett T, van den Toorn A, Sanchez-Perez GF, Campilho A, Willemsen V, Snel B, Scheres B
(2010) SOMBRERO, BEARSKIN1, and BEARSKIN2 regulate root cap maturation in
Arabidopsis. Plant Cell 22:640–654
Berger Y, Harpaz-Saad S, Brand A, Melnik H, Sirding N, Alvarez JP, Zinder M, Samach A,
Eshed Y, Ori N (2009) The NAC-domain transcription factor GOBLET specifies leaflet boundaries in compound tomato leaves. Development 136:823–832
NAC Transcription Factors in Woody Plants
215
NAC proteins are among the families of plant-specific TFs with the most number
of members. This is reflected in the variety of processes that they regulate, including
development, stress tolerance and wood formation. Most NAC proteins have a
modular organization formed by a conserved N-terminal DNA-binding domain
and by a C-terminal domain that is highly variable and plays a role in transcriptional
regulation and in protein–protein interaction. These TFs are able to be regulated by
alternative splicing, miRNA and post-translational modifications such as phosphorylation or ubiquitination; they can also interact with many different types of proteins.
Several NAC proteins associated with vascular development and stress responses
have been conserved along plant evolution, suggesting a prominent role of these
proteins in their survival and colonization of land habitats. Further, the bulk of the
tree biomass that is potentially useful for diverse purposes is based on the trees’ trunk
volume. Because NAC transcription factors are key regulators of the regulatory
network controlling wood formation, this raises the possibility of their use in
biotechnological processes to modify the quantity and potential quality of the
arboreal biomass.
Acknowledgements Research work in the authors’s laboratory was supported by grants from
“Ministerio de Economía y Competitividad” (BIO2015–69285-R) and the European Union
(FP7-KBBE-289841).
References
Aida M, Tetsuya I, Fukaki H, Fujisawa H, Tasaka M (1997) Genes involved in organ separation
in Arabidopsis: an analysis of the cup-shaped cotyledon mutant. Plant Cell 9:841–857
Aida M, Ishida T, Tasaka M (1999) Shoot apical meristem and cotyledon formation during
Arabidopsis embryogenesis: interaction among the CUP-SHAPED COTYLEDON and
SHOOT MERISTEMLESS genes. Development 126:1563–1570
Axtell MJ, Snyder JA, Bartel DP (2007) Common functions for diverse small RNAs of land plants.
Plant Cell 19:1750–1769
Barah P, Naika MBN, Jayavelu ND, Sowdhamini R, Shameer K, Bones AM (2016) Transcriptional
regulatory networks in Arabidopsis thaliana during single and combined stresses. Nucleic Acids
Res 44:3147–3164
Bedon F, Bomal C, Caron S, Levasseur C, Boyle B, Mansfield SD, Schmidt A et al (2010)
Subgroup 4R2R3-MYBs in conifer trees: gene family expansion and contribution to the
isoprenoid- and flavonoid-oriented responses. J Exp Bot 61:3847–3864
Bennett T, van den Toorn A, Sanchez-Perez GF, Campilho A, Willemsen V, Snel B, Scheres B
(2010) SOMBRERO, BEARSKIN1, and BEARSKIN2 regulate root cap maturation in
Arabidopsis. Plant Cell 22:640–654
Berger Y, Harpaz-Saad S, Brand A, Melnik H, Sirding N, Alvarez JP, Zinder M, Samach A,
Eshed Y, Ori N (2009) The NAC-domain transcription factor GOBLET specifies leaflet boundaries in compound tomato leaves. Development 136:823–832
NAC Transcription Factors in Woody Plants
215