How a Unique Tomato Mutation Could Transform Sustainable Agriculture
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“What started as curiosity about an intriguing
mutant has blossomed into a potentially transformative discovery for
sustainable agriculture,” said lead researcher Carmen Catalá, an adjunct assistant professor at BTI
and Senior Research Associate in the School of Integrative Plant Science at
Cornell.
The investigation, published in the Journal of Experimental Botany, focused on decoding the
mystery of a tomato mutant called “adpressa,” first
discovered in the 1950s. The mutant garnered attention because of an unusual
characteristic: adpressa plants are unable to
sense gravity. These plants often grow close to the ground rather than upward
toward the sky; hence, their name conveys a habit of being flat (adpressed)
against the soil.
The team led by Catalá, including BTI postdoctoral researchers Philippe Nicolas and Richard Pattison, began by uncovering the precise genetic change causing this fascinating effect. They found that the mutation blocks the synthesis of starch, which is a storage form of sugar.
The team pushed further, using the mutation
to investigate fundamental questions about fruit biology. They discovered that
the mutant shows major transcriptional and metabolic adjustments, including
increased levels of soluble sugars and enhanced growth. More surprisingly was
the discovery of complete resistance to blossom-end rot (BER), a physiological
disorder causing deterioration of fruit’s cell membranes and a dry, black, and
sunken area on the bottom of the tomatoes.
Often noticed by gardeners and commercial
growers, BER incidence is difficult to predict but has been directly related to
environmental stresses such as temperature or irregular watering. BER also
affects other fruits and vegetables, including peppers, squash, cucumber, and
melon. Although this complex disorder has been intensively studied, mechanisms
underlying BER development are not fully understood.
“Our findings with the adpressa mutant are quite promising. Contrary to
what was previously thought, the lack of starch did not alter fruit development
and ripening. In fact, adpressa fruits
were slightly larger and accumulated more sugars during growth. The most
remarkable discovery is the resistance to blossom-end rot. These findings open
new avenues for improving fruit yield and quality, especially under stressful
environmental conditions,” noted Nicolas.
The research team at BTI collaborated with
scientists from the Max Planck Institute in Germany, the Instituto de
Hortofruticultura Subtropical y Mediterránea “La Mayora” in Málaga, Spain, and
the US Department of Agriculture. Together, they utilized advanced genomic and metabolic
analysis tools to study how the mutation affects fruit development.
“The intricate connection we observed
between sugar metabolism and resistance to cellular damage in fruit tissues is
particularly fascinating. This study reveals the potential for engineering or
breeding tomatoes that can better withstand environmental challenges,” said
Nicolas.
The team is now working on understanding
why these mutants are resilient against abiotic stresses and expect to find
target genes or compounds with an essential role in BER resistance.
“We hope this discovery will lead to novel
approaches in creating plants resistant to blossom-end rot and other types of
stress-induced damage,” said Catalá. “Not only would it benefit gardeners and
commercial growers, but it would have a significant impact in countries with
adverse growing conditions, where small farmers do not have the resources to
protect their crops from environmental challenges such as drought.”