From little things_ big things grow

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From little things,
big things grow
Genes are one of the major factors that control grain quality and development
traits such as seed size, vigour and quality. Working to control genes, however, is
other biological ‘machinery’ that may help to determine very precisely when
genes, particularly important regulatory genes, turn on. Researchers at CSIRO
Plant Industry are looking at some of this biological machinery, namely ‘micro
RNAs’, to determine just what role they play in grain development in cereals.

Grain traits

Cereal grain
determines the
price of the grain
the grower
receives and the
grain’s end use.
It includes the
composition of
the grain (for
example, how
much protein it
contains), seed
size and vigour –
all key traits that
breeders try and
improve in new
                      Dr Chris Helliwell and his team at CSIRO Plant Industry are leading the way
                      into understanding how micro RNAs influence grain development traits in rice.
Grain quality
starts when the
grain is forming.
It is at this point that certain genes              Micro RNAs
activate to work together to develop
the grain and its characteristics.                  RNA is a close cousin of DNA, but it is
                                                    a single strand rather than DNA’s well
Environmental and external factors,                 recognised double helix ladder. Micro
such as rain and nutrient availability,             RNAs are tiny pieces of RNA,
will influence the grain quality, but it            equivalent to 21-23 rungs on the DNA
is the genes that are the underlying                double helix ladder. They have been
influence that dictate the potential of             shown to be precise controllers of
the grain quality that can then be                  where and when important regulatory
realised in ideal environmental                     genes are turned on.
                                                    Dr Chris Helliwell and his team of
                                                    CSIRO Plant Industry scientists will
                                                    hunt for new micro RNAs in rice then
                                                    look to see whether they, and other
                                                    previously identified micro RNAs, are
                                                    active during grain development.
They will then investigate how the                                                   Working with rice

                                                                                                                                                           Produced by CSIRO Plant Industry Communication Group 2007
active micro RNAs in rice grains are
acting in grain development – in                                                     Rice is the only cereal crop that has
particular whether they are controlling                                              had its genome fully sequenced. This
any known grain development genes.                                                   makes it a really easy crop to do
                                                                                     genetic research in, such as hunting
It is likely that some of the micro                                                  for micro RNAs.
RNAs active during grain development
are linked to other undiscovered grain                                               The added advantage is that because
development genes, so the micro                                                      rice is related to other cereal crops
RNAs could be a pointer to new genes                                                 knowledge gained from research done
involved in grain development.                                                       in rice will be much more easily
                                                                                     transferred across to other cereal
                                                                                     crops like wheat.

                                                                                                                     understanding of the
                                                                                                                     role of micro RNAs in
                                                                                                                     grain development in
                                                                                                                     rice could lead to the
                                                                                                                     development of new
                                                                                                                     cereal crops with
                                                                                                                     improved grain
                                                                                                                     quality traits.

                                                                               Understanding the role of
                                                                               micro RNAs in grain
                                                                               development in rice
                                                                               (above) could lead to new
                                                                               cereal varieties, like wheat
                                                                               (below), with improved
                                                                               grain quality traits.

                                                                                                             For further information contact:
                                                                                                                                    CSIRO Enquiries
                                                                                                                      Bag 10 Clayton South VIC 3169

                                                                                                            Phone: 1300 363 400 (National local call)
                                                                                                              +61 3 95452176 (International phone)

                                                                                                                                 Fax: +61 3 9545 2175



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