such as "Introduction", "Conclusion"..etc
February 7, 2009 — The global climate is
changing, and this change is already impacting food supply and
security. People living in regions already affected by aridity need
plants that can thrive / grow under dry conditions.
One example is sorghum: Also known as milo, durra, or broomcorn,
sorghum is a grass species that can grow up to five meters in height
and is extremely resistant to aridity and hot conditions. The grass,
which originates from Africa, can thrive under conditions and locations
where other cereal plants cannot survive due to lack of water. In
arid-warm and moderate regions of the Americas, Asia and Europe it is
mainly utilized for food and fodder and is also gaining in significance
as a basis for bio-fuel. The plant also provides fibers as well as
combustible material for heating and cooking.
As part of an international consortium of scientists, researchers at
Helmholtz Zentrum München are analyzing the genes of sorghum, the first
plant of African origin whose genome has been sequenced.
Dr. Klaus Mayer of the Institute of Bioinformatics and Systems
Biology of the Helmholtz Zentrum München described the scientists’
research goal: ”We want to elucidate the functional and structural
genomics of sorghum.“ He went on to explain: ”That is the prerequisite
for making this important grain even more productive through targeted
breeding strategies. As German Research Center for Environmental
Health, sustaining the food supply is one of our most important
research topics. That is why we are trying to learn something about the
molecular basis of the plant’s pronounced drought tolerance in order to
apply this knowledge to other crop plants in our latitude zone as well.
“The first results of the study have been published in the current
issue of Nature.
What makes sorghum interesting as a model system is that it is more
closely related to the predominant grains of tropical origin, for
example maize, than it is to rice. Moreover, sorghum, unlike many other
crop plants, has not undergone genome enlargement in the past millions
of years. Its rather small genome – about one-fourth as large as the
human genome – is a good starting point for investigating the more
complex genomes of important crop plants such as maize or sugarcane,
especially since sorghum - like these two plants –is a ”C4 plant“.
Due to biochemical and morphological specialization, such plants use
a special kind of photosynthesis (in which first a molecule with four
carbon atoms is formed, thus the name). They can assimilate carbon at
higher temperatures and more efficiently than ”C3 plants“ and are
especially suitable for the production of biomass for energy. Sorghum
is the first cereal plant with C4 photosynthesis whose genome has been
completely sequenced. The analysis of its functional genomics provides
new insights into the molecular differences between C3 and C4 plants.
Furthermore, the comparison with the C3 plant rice - likewise
completely sequenced – gives us information about how these cereals
became more divergent in the course of evolution.The data of the Munich
scientists also allow a comparative analysis of sorghum, rice and
maize. This analysis yields information about the evolution of the
genome size, distribution and amplification of genes or recombination
Last but not least, the researchers have validated a method in their
study - whole genome shotgun sequencing – which is an especially fast
and inexpensive method of sequencing complete chromosomes and genomes.
In this method, the DNA is copied multiple times and then shredded into
many small fragments by squeezing the DNA through a pressurized
syringe. Finally the fragments are sequenced from both ends ans
subsequentially the millions of small DNA fragments are assembled by
elaborate computational methods into complete chromosomes.
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