Modulating auxin response stabilizes tomato fruit set

Area of Science:

• Plant Biology
• Genetics
• Agricultural Science

Background:

• Fruit set and growth are crucial for crop yield but are sensitive to environmental stress.
• Auxin signaling pathways, particularly auxin response factors (ARFs), play a key role in regulating fruit development.
• Class A ARFs act as molecular switches, modulating gene transcription in response to auxin levels.

Purpose of the Study:

• To investigate the role of multiple ARF family members in fruit set and growth in tomato and Arabidopsis.
• To determine if reducing SlARF activity can enhance yield stability in tomato under fluctuating temperatures.

Main Methods:

• Analysis of various tomato (Solanum lycopersicum) and Arabidopsis thaliana mutant combinations affecting ARF genes.
• Phenotypic characterization of fruit set, parthenocarpy, and fruit growth in wild-type and mutant plants.
• Evaluation of tomato plant yield performance under controlled and ambient fluctuating temperature conditions, including field trials.

Main Results:

• Mutations in SlARF8A and SlARF8B in tomato led to seedless parthenocarpic fruit development.
• Arabidopsis Atarf8 mutants showed less parthenocarpy, while Atarf6 Atarf8 double mutants exhibited reduced fruit growth.
• Tomato plants with reduced SlARF8A/B gene dosage exhibited significantly higher yields under hot and cold conditions.
• Field trials confirmed increased yield under extreme temperatures with partial SlARF8 reduction, attributed to earlier fruit set and more fruit-bearing structures.

Conclusions:

• ARF8 proteins are key mediators controlling fruit set in tomato.
• Reducing ARF8 activity through SlARF8 mutations offers a promising strategy for breeding crops with improved yield stability against environmental fluctuations.
• This approach has potential applications in enhancing tomato and other crop yields in challenging agricultural conditions.