ID | 63814 |
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Author |
Mitalo, Oscar W.
Graduate School of Environmental and Life Science, Okayama University
Asiche, William O.
Department of Research and Development, Del Monte Kenya Ltd
Kang, Seung W.
Graduate School of Life and Environmental Sciences, University of Tsukuba
Ezura, Hiroshi
Graduate School of Life and Environmental Sciences, University of Tsukuba
Akagi, Takashi
Graduate School of Environmental and Life Science, Okayama University
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Kubo, Yasutaka
Graduate School of Environmental and Life Science, Okayama University
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Ushijima, Koichiro
Graduate School of Environmental and Life Science, Okayama University
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Abstract | Peel degreening is the most conspicuous aspect of fruit ripening in many citrus fruits because of its importance for marketability. In this study, peel degreening in response to propylene (an ethylene analog) and at varying storage temperatures was characterized in Satsuma mandarin (Citrus unshiu Marc.) fruit. Propylene treatment triggered rapid peel degreening (within 4-6 days), indicated by an increase in the citrus color index (CCI) and chlorophyll loss. Peel degreening was also observed in fruit at 10 degrees C and 15 degrees C after 28-42 days, with gradual CCI increase and chlorophyll reduction. However, fruit at 5 degrees C, 20 degrees C, and 25 degrees C remained green, and no substantial changes in peel CCI and chlorophyll content were recorded during the 42-day storage duration. The transcriptomes of peels of fruit treated with propylene for 4 days and those stored at varying temperatures for 28 days were then analyzed by RNA-Seq. We identified three categories of differentially expressed genes that were regulated by (i) propylene (and by analogy, ethylene) alone, (ii) low temperature (5 degrees C, 10 degrees C, or 15 degrees C vs. 25 degrees C) alone, and (iii) either propylene or low temperature. Gene-encoding proteins associated with chlorophyll degradation (such as CuSGR1, CuNOL, CuACD2, CuCAB2, and CuLHCB2) and a transcription factor (CuERF114) were differentially expressed by propylene or low temperature. To further examine temperature-induced pathways, we also monitored gene expression during on-tree fruit maturation vs. postharvest. The onset of on-tree peel degreening coincided with autumnal drops in field temperatures, and it was accompanied by differential expression of low temperature-regulated genes. On the contrary, genes that were exclusively regulated by propylene (such as CuCOPT1 and CuPOX-A2) displayed insignificant expression changes during on-tree peel degreening. These findings indicate that low temperatures could be involved in the fruit ripening-related peel degreening independently of ethylene.
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Keywords | chlorophyll
citrus
degreening
ethylene
RNA-Seq
on-tree
storage
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Published Date | 2022-07-13
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Publication Title |
Frontiers In Plant Science
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Volume | volume13
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Publisher | Frontiers Media SA
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Start Page | 918226
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ISSN | 1664-462X
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Content Type |
Journal Article
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language |
English
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OAI-PMH Set |
岡山大学
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Copyright Holders | © 2022 Mitalo, Asiche, Kang, Ezura, Akagi, Kubo and Ushijima.
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File Version | publisher
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PubMed ID | |
DOI | |
Web of Science KeyUT | |
Related Url | isVersionOf https://doi.org/10.3389/fpls.2022.918226
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License | https://creativecommons.org/licenses/by/4.0/
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Funder Name |
Japan Society for the Promotion of Science
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助成番号 | 20H02977
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