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
Researchers develop eco-friendly, 4-in-1 catalyst
25.04.2017 | Brown University
Transfecting cells gently – the LZH presents a GNOME prototype at the Labvolution 2017
25.04.2017 | Laser Zentrum Hannover e.V.
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
20.04.2017 | Event News
18.04.2017 | Event News
03.04.2017 | Event News
25.04.2017 | Physics and Astronomy
25.04.2017 | Materials Sciences
25.04.2017 | Life Sciences