Characterization and Identification of a Ripening-Related Gene <i>AaPG18</i> in <i>Actinidia arguta</i>
<i>A</i><i>ctinidia arguta</i> (<i>A. arguta</i>) is a kind of climacteric fruit that quickly softens and limits fruit shelf-life and commercial value. Therefore, it is of great significance to develop kiwifruit genotypes with an extended shelf-life of fruit. Howe...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2022-02-01
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| Series: | International Journal of Molecular Sciences |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1422-0067/23/5/2597 |
| Summary: | <i>A</i><i>ctinidia arguta</i> (<i>A. arguta</i>) is a kind of climacteric fruit that quickly softens and limits fruit shelf-life and commercial value. Therefore, it is of great significance to develop kiwifruit genotypes with an extended shelf-life of fruit. However, the ripening and softening mechanisms remain unclear in <i>A. arguta</i>. Here, we demonstrated that a key polygalacturonase (PG)-encoding gene <i>AaPG18</i> was involved in <i>A. arguta</i> ripening through the degradation of the cell wall. Fruits were harvested at three developmental stages (S1, S2, and S3) for high-throughput transcriptome sequencing, based on which two candidate transcripts <i>c109562_g1</i> and <i>c111961_g1</i> were screened. The genome-wide identification of the PG gene family assigned <i>c109562_g1</i> and <i>c111961_g1</i> to correspond to <i>AaPG4</i> and <i>AaPG18</i>, respectively. The expression profiles of candidate genes at six preharvest stages of fruit showed significantly higher expression levels of <i>AaPG18</i> than <i>AaPG4</i>, indicating <i>AaPG18</i> might be a key gene during fruit ripening processes. The subcellular localization displayed <i>AaPG18</i> was located at the cytoplasmic membrane. The transient overexpression of <i>AaPG18</i> in strawberry and the following morphological observation suggested <i>AaPG18</i> played a key role in maintaining the stability of cell morphology. The homologous transient transformation in <i>A. arguta</i> “RB-4” proved the crucial function of <i>AaPG18</i> in fruit ripening processes by causing the rapid redness of the fruit, which was an indicator of fruit maturity. All in all, our results identified <i>AaPG18</i> as a key candidate gene involved in cell wall degeneration, which provides a basis for the subsequent exploration of the molecular mechanisms underlying the ripening and softening of <i>A. arguta</i> fruit. |
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| ISSN: | 1661-6596 1422-0067 |