2017 ASHS Annual Conference

Strawberry fruit have been considered as non-climacteric fruit and abscisic acid (ABA) is generally known as a main hormone to trigger ripening of strawberry fruit. However, the roles of other major plant hormones and ripening mechanism of strawberry fruit have not been well studied clearly. To understand hormonal regulation mechanism of strawberry fruit ripening, we exactly analyzed five major hormones of ABA, indole-3-acetic acid (IAA), gibberellin 4 (GA4), and methyl- jasmonate (MJ), and ethylene (ET) according to strawberry fruit development stages. The quantification of hormones was conducted at six developmental stages: SG, small green; LG, green; BR, breaker; PK, pink; and FR, fully red. IAA, GA4, and ABA were analyzed by a high-performance liquid chromatography-mass spectrometry. MJ was analyzed by gas chromatography–mass spectrometry. IAA and GA4 levels had the highest levels at SG stage and gradually declined during fruit development. The level of ABA was low at SG and BR stages and then rapidly increased by showing the maximum value at FR. In contrast, the level of MJ did not significantly changed during fruit development stage. ET was not detected in all fruit development stages. Additionally, the ABA biosynthesis genes of FaNCED1 and FaNCED2 had positive correlations with fruit ripening and the ABA degradation gene of FaCYP707A1 encoding 8-hydroxylase had a negative correlation with fruit ripening. Therefore, the ripening of strawberry fruit would be controlled under the changes of ABA and its related gene expressions which are FaNCED1, FaNCED2, and FaCYP707A1.