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Ferrochelatase deficiency causes a striped phenotype in barley Tigrina-b mutants

Nesic, Mina (2024) MOBN03 20232
Degree Projects in Molecular Biology
Popular Abstract
A mutation in ferrochelatase causes the tiger-like appearance of barley mutants

The study of plants provides people with knowledge that can be used for a variety of purposes, including advances in agriculture, food production and nature conservation. Barley is an important crop that was domesticated about 10,000 years ago. It can self-fertilize, rarely crosses with other plant species and a single barley plant can produce many offspring. These traits make barley particularly useful for plant genetic studies.

By using different physical or chemical treatments, mutations were introduced into the barley genome, which is organized into seven chromosomes. Even though most of the mutations were not economically beneficial, they were... (More)
A mutation in ferrochelatase causes the tiger-like appearance of barley mutants

The study of plants provides people with knowledge that can be used for a variety of purposes, including advances in agriculture, food production and nature conservation. Barley is an important crop that was domesticated about 10,000 years ago. It can self-fertilize, rarely crosses with other plant species and a single barley plant can produce many offspring. These traits make barley particularly useful for plant genetic studies.

By using different physical or chemical treatments, mutations were introduced into the barley genome, which is organized into seven chromosomes. Even though most of the mutations were not economically beneficial, they were important from a scientific point of view, considering that they provided a better insight into the molecular processes ocurring in plant cells. This study was focused on a Tigrina-b mutant, which is recognized by alternating transverse green and yellow stripes. It has been discovered that mutations in the ferrochelatase gene cause the striped appearance of the Tigrina-b mutants.

Using bioinformatics tools, it was discovered that the mutation is located on chromosome 1 and a list of genes that might carry the mutation was obtained. The most promising candidate was the ferrochelatase gene, which encodes an enzyme that produces heme. Given that heme shares the first part of its biosynthetic pathway with chlorophyll, it was assumed that a mutation in the ferrochelatase gene could disrupt chlorophyll biosynthesis. After sequencing the ferrochelatase gene in several different Tigrina-b mutants, a mutation was found in all cases, proving that ferrochelatase is a protein product of the Tigrina-b gene.

Regulatory role of ferrochelatase 2
Plants are known to possess two ferrochelatases, referred to as ferrochelatase 1 and ferrochelatase 2. Through comparison with another plant model organism, Arabidopsis thaliana, it was found that the barley Tigrina-b gene corresponds to ferrochelatase 2. Previous studies showed that ferrochelatase 2 stabilizes a protein complex that inhibits the production of 5-aminolevulinic acid, a common precursor of chlorophyll and heme, in the dark. This prevents the further accumulation of a compound that can burn the plant when exposed to light. We suggest that a mutation in the Tigrina-b gene disturbs the function of ferrochelatase 2 and, therefore, the stability of the regulatory complex. As a result, Tigrina-b mutants undergo bleaching upon exposure to light, causing the appearance of yellow stripes.

Master’s Degree Project in Molecular Biology, 60 credits, 2024
Department of Biology, Lund University

Advisor: Mats Hansson
Division of Molecular Biosciences (Less)
Please use this url to cite or link to this publication:
author
Nesic, Mina
supervisor
organization
course
MOBN03 20232
year
type
H2 - Master's Degree (Two Years)
subject
language
English
id
9176250
date added to LUP
2024-10-07 15:55:19
date last changed
2024-10-07 15:55:19
@misc{9176250,
  author       = {{Nesic, Mina}},
  language     = {{eng}},
  note         = {{Student Paper}},
  title        = {{Ferrochelatase deficiency causes a striped phenotype in barley Tigrina-b mutants}},
  year         = {{2024}},
}