Mutant tomato helps to crack the secrets of fruiting

Date:
September 10, 2020
Source:
University of Tsukuba
Summary:
Researchers have found that fruit development in tomatoes rewires
their central metabolism. The plant hormone gibberellin, which
regulates major parts of plant development, triggers the process of
fruiting. Using a mutant strain of tomato that is highly sensitive
to gibberellin, the study showed that the central metabolism
pathway in tomatoes was consistently rewired via gibberellin
activity. These results could lead to new production strategies,
such as breeding seedless fruit.



FULL STORY ==========================================================================
It may sound like something out of a science fiction B-movie, but with
the help of a mutant tomato, researchers from Japan have discovered that
the development process of fruit rewires their central metabolism pathway.


==========================================================================
In a study published this month in Proceedings of the National Academy
of Sciences (PNAS), researchers from the University of Tsukuba have
revealed that "fruit set" -- the fruit development process in plants --
rewired the central metabolism pathway in tomatoes via an increased
sensitivity to the plant hormone gibberellin.

Tomatoes, although commonly thought of as vegetables, are actually
fruit. Fruit set is the process whereby plant ovaries develop into fruits
after pollination and fertilization, and in tomatoes the process is
triggered by gibberellin. But the role of this hormone in the metabolic processes of fruit-setting ovaries is still mostly unknown.

"Pollination is usually key to bringing on fruit set, because it
stimulates the buildup of plant growth hormones, including gibberellin,
inside fertilized ovaries," says lead author of the study Professor
Tohru Ariizumi. "Gibberellins stimulate aspects of plant development,
such as fruit set, and trigger rapid ovary growth." To examine fruit set
in tomatoes, the researchers used multi-omics - - specifically, looking
at all the RNA, proteins, and small-molecule metabolites produced during metabolism -- and enzyme activity data.

Additionally, they used kinetic modelling to look at the earliest
processes that occur during fruit set. Ovary growth during fruit set
was measured using wild-type and procera mutant tomatoes, which are hypersensitive to gibberellin.

"Applying hormones like gibberellin to ovaries or genetic mutations
in the negative regulatory genes of hormone cascades can bring on parthenocarpy," explains Professor Ariizumi. "Parthenocarpy is fruit
set that is independent of pollination." Gibberellins are signaling
molecules that trigger signal transduction cascades -- i.e., they
activate or repress downstream genes that are responsible for carrying
out particular developmental and growth processes.

"Our study looked at the biochemical mechanisms of fruit set. Our analysis
was able to define the genes, proteins, enzymes and metabolites that
were consistently affected by both pollination and procera-induced parthenocarpy, and highlighted that the central metabolism was
consistently rewired," says Professor Ariizumi.

The results of this study contribute to a better understanding of fruit
set metabolism, which will lead to new strategies for production. In particular, it may be possible to breed for parthenocarpic fruits
(which are seedless), and to increase control of fruit survival during
the early stages of development.


========================================================================== Story Source: Materials provided by University_of_Tsukuba. Note: Content
may be edited for style and length.


========================================================================== Journal Reference:
1. Yoshihito Shinozaki, Bertrand P. Beauvoit, Masaru Takahara,
Shuhei Hao,
Kentaro Ezura, Marie-He'le`ne Andrieu, Keiji Nishida,
Kazuki Mori, Yutaka Suzuki, Satoshi Kuhara, Hirofumi Enomoto,
Miyako Kusano, Atsushi Fukushima, Tetsuya Mori, Mikiko Kojima,
Makoto Kobayashi, Hitoshi Sakakibara, Kazuki Saito, Yuya Ohtani,
Camille Be'nard, Duyen Prodhomme, Yves Gibon, Hiroshi Ezura, Tohru
Ariizumi. Fruit setting rewires central metabolism via gibberellin
cascades. Proceedings of the National Academy of Sciences, 2020;
202011859 DOI: 10.1073/pnas.2011859117 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/09/200910100614.htm

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