Indoor horticulture offers a promising solution for sustainable food production and
is becoming increasingly widespread. However, it incurs high energy and cost
due to the use of artificial lighting such as high-pressure sodium lamps,
fluorescent light or increasingly, the light-emitting diodes (LEDs). The energy
efficiency and light quality of currently available lighting is suboptimal, therefore
less than ideal for sustainable and cost-effective large-scale plant production.
Here, we demonstrate the use of high-powered single-wavelength lasers for
indoor horticulture. Lasers are highly energy-efficient and can be remotely guided
to the site of plant growth, thus reducing on-site heat accumulation. Besides,
laser beams can be tailored to match the absorption profiles of different plants.
We have developed a prototype laser growth chamber and demonstrate that
laser-grown plants can complete a full growth cycle from seed to seed with
phenotypes resembling those of plants grown under LEDs. Importantly, the
plants have lower expression of proteins diagnostic for light and radiation stress.
The phenotypical, biochemical and proteomic data show that the singlewavelength
laser light is suitable for plant growth and therefore, potentially able to unlock the advantages of this next generation lighting technology for highly
energy-efficient horticulture. Furthermore, stomatal movement partly determines
the plant productivity and stress management. Abscisic acid (ABA) induces
stomatal closure by promoting net K+-efflux from guard cells through outwardrectifying
K+ (K+ out) channels to regulate plant water homeostasis. Here, we show
that the Arabidopsis thaliana guard cell outward-rectifying K+ (ATGORK) channel
is a direct target for ABA in the regulation of stomatal aperture and hence gas
exchange and transpiration. Addition of (±)-ABA, but not the biologically inactive
(−)-isomer, increases K+ out channel activity in Vicia faba guard cell protoplast. A
similar ABA-modulated K+ channel conductance was observed when ATGORK
was heterologously expressed in human embryonic kidney 293 (HEK-293) cells.
Alignment of ATGORK with known PYR/PYL/RCARs ABA receptors revealed
that ATGORK harbors amino acid residues that are similar to those at the latchlike
region of the ABA-binding sites. In ATGORK, the double mutations K559A
and Y562A at the predicted ABA-interacting site impaired ABA-dependent
channel activation and reduced the affinity for ABA in vitro.
|Date of Award||Dec 2016|
- Biological, Environmental Science and Engineering
|Supervisor||Liming Xiong (Supervisor)|
- laser-based indoor horticulture
- Abscisic Acid
- Guard cell outward-rectifying potassium (GORK)