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Identification of Viridis-k: An Essential Gene for Chlorophyll Biosynthesis in Barley

Stuart, David (2017) MOBT01 20162
Degree Projects in Molecular Biology
Popular Abstract
Hunting a Gene That Makes Plants Green

Photosynthesis is the process plants use to obtain energy from sunlight. In doing so, they produce oxygen and sugars, which supports life on earth as we know it. To harvest sunlight, plants use pigments know as chlorophylls, which also give plants their distinctive green color. Chlorophyll is a cyclic tetrapyrrole which is similar in structure to heme, the compound responsible for the red color of blood. One of the main differences between heme and chlorophyll is that chlorophyll contains a fifth ring structure, which is formed by a reaction known as the cyclase reaction. Using barley mutants, next-generation DNA sequencing techniques, and genetic mapping, we have identified one of the genes... (More)
Hunting a Gene That Makes Plants Green

Photosynthesis is the process plants use to obtain energy from sunlight. In doing so, they produce oxygen and sugars, which supports life on earth as we know it. To harvest sunlight, plants use pigments know as chlorophylls, which also give plants their distinctive green color. Chlorophyll is a cyclic tetrapyrrole which is similar in structure to heme, the compound responsible for the red color of blood. One of the main differences between heme and chlorophyll is that chlorophyll contains a fifth ring structure, which is formed by a reaction known as the cyclase reaction. Using barley mutants, next-generation DNA sequencing techniques, and genetic mapping, we have identified one of the genes required for forming the fifth ring of chlorophyll. In barley, this gene is named Viridis-k, and encodes a type of protein known as a ferredoxin. Without this gene, plants cannot produce chlorophyll and do not turn green as can be seen in the figure to the right.

All our food is either directly or indirectly produced by photosynthesis performed by plants. Therefore it is important to have a complete understanding of all genes required for photosynthesis, which will hopefully allow breeding of more productive crops. In turn, more productive crops would help feed the growing world population and decrease the carbon footprint from agriculture. Since the cyclase reaction is one of the only steps of chlorophyll biosynthesis with unidentified genes, the identification of the Viridis-k gene brings us one step closer to a complete understanding of this process.

Another interesting aspect of this finding is the type of gene that Viridis-k is, a ferredoxin. Classical plant ferredoxins are proteins that contain iron-sulphur clusters and deliver energized electrons produced by photosynthesis to metabolic reactions where the electrons can be used or stored. This can be thought of as a biological circuit, much like the circuit board in your cell phone, which transfers electrons from the battery to the screen, microphone, speakers, and so on. Understanding how this biological circuit board allocates photosynthetic electrons to different processes is of paramount importance. In the future this will not only allow breeding of improved crop plants but also allow for biotechnological applications like the use of genetically engineered algae as factories to produce chemicals using only sunlight as energy. Algal factories would even remove carbon dioxide from the atmosphere in the process, thus making them literally figuratively green. Going forward, it will be interesting to discover how Viridis-k fits in to this complex circuitry.

Master’s Degree Project in Molecular Biology 60 credits 2016-17
Department of Biology, Lund University

Advisor: Mats Hansson
Molecular Cell Biology Unit (Less)
Please use this url to cite or link to this publication:
author
Stuart, David
supervisor
organization
course
MOBT01 20162
year
type
H2 - Master's Degree (Two Years)
subject
language
English
id
8925915
date added to LUP
2017-09-18 16:22:33
date last changed
2017-09-19 09:05:46
@misc{8925915,
  author       = {Stuart, David},
  language     = {eng},
  note         = {Student Paper},
  title        = {Identification of Viridis-k: An Essential Gene for Chlorophyll Biosynthesis in Barley},
  year         = {2017},
}