Every vascular plant contains an extensive network of xylem and phloem, specialized tissues that respectively transport water and nutrients throughout the plant body. Untangling the processes that determine how these two types of vasculature develop has proven challenging, but a team led by Taku Demura of the RIKEN Biomass Engineering Program in Wako has now uncovered an important novel regulator of xylem formation1.
Several years ago, Demura and colleagues identified a family of seven VASCULAR-RELATED NAC-DOMAIN (VND) transcription factors; one of these, VND7, appears to activate a number of genes related to xylem development2. “The data suggest that VND7 likely functions as the principal regulator of vessel differentiation,” Demura says. However, the activity of this factor appears to depend closely on the proteins with which it partners, and his team has subsequently focused on identifying these co-regulators.
In their most recent screen, the researchers identified VNI2, a novel transcriptional regulator that physically interacts with VND7 and whose expression appears to correlate closely with vascular development in both root and stem tissue. However, although both VND7 and VNI2 are categorized as ‘NAC domain’ proteins, VNI2 exhibited one surprising difference from other members of its family. “It is known that most of the NAC transcription factors are transcriptional activators,” says Demura. “In contrast, VNI2 is a transcriptional repressor.”
Indeed, VNI2 appears to act primarily as an inhibitor of vascular development, and plants overexpressing this factor exhibited profound defects in xylem formation. These abnormalities were highly similar to those observed in plants overexpressing modified, inhibitory variants of VND7, further supporting a partnership between these two factors. In parallel, Demura and colleagues determined that VNI2 specifically represses several genes known to be induced by VND7 in the course of xylem differentiation.
These findings indicate that the VNI2–VND7 complex contributes directly to the timing and localization of vascular development, although this is most likely not the sole purpose of this repressor. “Our paper shows that VNI2 is expressed in various other cell types in addition to xylem vessels, and we want to know its other functions,” says Demura. Accordingly, their initial protein–protein interaction data suggest that VNI2 might pair with other, non-xylem-specific NAC proteins, whose functional characteristics remain enigmatic.
“We still need to study the VND genes [more closely],” says Demura, “for a better understanding of xylem cell differentiation. Since xylem cells are a major source of lignocellulosic biomass, such knowledge could be applied to potential renewable materials and biofuels.”
The corresponding author for this highlight is based at the Cellulose Production Research Team, RIKEN Biomass Engineering Program
1. Yamaguchi, M., Ohtani, M., Mitsuda, N., Kubo, M., Ohme-Takagi, M., Fukuda, H. & Demura, T. VND-INTERACTING2, a NAC domain transcription factor, negatively regulates xylem vessel formation in Arabidopsis. Plant Cell 22, 1249–1263 (2010).
2. Kubo, M., Udagawa, M., Nishikubo, N. Horiguchi, G., Yamaguchi, M., Ito, J., Mimura, T., Fukuda, H. & Demura, T. Transcription switches for protoxylem and metaxylem vessel formation. Genes & Development 19, 1855–1860 (2005).
gro-pr | Research asia research news
Discovery of a Key Regulatory Gene in Cardiac Valve Formation
24.05.2017 | Universität Basel
Carcinogenic soot particles from GDI engines
24.05.2017 | Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt
Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.
The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....
An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.
We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...
Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.
Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...
An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...
In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.
In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...
24.05.2017 | Event News
23.05.2017 | Event News
22.05.2017 | Event News
24.05.2017 | Physics and Astronomy
24.05.2017 | Physics and Astronomy
24.05.2017 | Event News