Natural Variation in the <i>AAT1</i> Promoter Is Responsible for the Disparity in Ester Aroma Between <i>Actinidia chinensis</i> and <i>Actinidia eriantha</i>
To understand ester compound biosynthesis in kiwifruit, two Actinidia species with distinct characteristics were compared. The firmness of Donghong (<i>Actinidia chinensis</i>) and Ganlv-1 (<i>Actinidia eriantha</i>) fruits gradually decreased as the fruit ripened after harve...
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| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2024-12-01
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| Series: | Agronomy |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2073-4395/14/12/2965 |
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| Summary: | To understand ester compound biosynthesis in kiwifruit, two Actinidia species with distinct characteristics were compared. The firmness of Donghong (<i>Actinidia chinensis</i>) and Ganlv-1 (<i>Actinidia eriantha</i>) fruits gradually decreased as the fruit ripened after harvest, whereas the total soluble solids increased continuously, reaching a peak on the 8th day. The Ganlv-1 fruit ester content was significantly lower than in the Donghong fruits at the optimal eating stage, and the alcohol acyltransferase (AAT) activity in the Ganlv-1 fruits was significantly lower than in the Donghong fruits. The gene expression levels of <i>AAT1</i> and <i>AAT17</i> in the Donghong fruits were significantly higher than in the Ganlv-1 fruits, with a particularly remarkable difference observed for <i>AAT1,</i> which exhibited a 36-fold higher expression in the Donghong fruits when compared with the fully ripened Ganlv-1 fruits. A transient overexpression of the <i>AAT1</i> gene in the kiwifruit led to a significant increase in ester content. Interestingly, a natural variation was observed in the promoter sequence of <i>AAT1</i> between the Donghong and Ganlv-1 cultivars. Furthermore, separate analyses of the respective promoter activities revealed significantly higher activity levels in the Donghong fruits than in the Ganlv-1 fruits. In conclusion, a natural variation in the <i>AAT1</i> promoter is primarily responsible for the disparity in <i>AAT1</i> gene expression between the Donghong and Ganlv-1 fruits, resulting in a divergent accumulation of ester aroma compounds during the postharvest ripening stages. |
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| ISSN: | 2073-4395 |