Interplays between auxin and GA signaling coordinate early fruit development

Phytohormones and their interactions are critical for fruit development and, are key topics in horticulture research. Auxin, together with gibberellic acid (GA), promotes cell division and expansion, thus subsequently regulates fruit development and enlargement after fertilization. Auxin and GA related mutants show parthenocarpy (fruit formation without fertilization of ovule) in many plant species, indicating that these hormones and possibly their interactions play a key role in the regulation of fruit initiation and development. Recent studies have shown clear molecular and genetic evidence that ARF/IAA and DELLA protein interact each other and regulate both auxin and GA signaling pathways in response to auxin and GA during fruit growth in horticultural plants, tomato (the most studied freshy fruit) and strawberry (the model of Rosaceae). These recent findings provide new insights into the mechanisms by which plant hormones auxin and GA regulate fruit development.