Hypoxia‐responsive ERFs involved in postdeastringency softening of persimmon fruit

• Published in: Plant biotechnology journal Vol. 15; no. 11; pp. 1409 - 1419
• Main Authors: Wang, Miao‐miao, Zhu, Qing‐gang, Deng, Chu‐li, Luo, Zheng‐rong, Sun, Ning‐jing, Grierson, Donald, Yin, Xue‐ren, Chen, Kun‐song
• Format: Journal Article
• Language: English
• Published: England John Wiley & Sons, Inc 01.11.2017; John Wiley and Sons Inc
• Subjects: 1-methylcyclopropene; Acetaldehyde; Anaerobic digestion; Anaerobic treatment; astringency; Astringency removal; Astringents; Carbon dioxide; Carbon Dioxide - metabolism; Cell Wall - enzymology; Cell Wall - metabolism; Cell walls; Cultivars; Cyclopropanes; Dehydration; Diospyros - enzymology; Diospyros - genetics; Diospyros - growth & development; Diospyros - metabolism; Enzymes; ERF; Ethylene; ethylene inhibitors; Ethylenes - pharmacology; Firmness; Fruit - enzymology; Fruit - genetics; Fruit - growth & development; Fruit - metabolism; fruit quality; Fruits; Gene expression; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Plant - drug effects; Genes; Genes, Plant; high CO2; Hypoxia; Hypoxia - genetics; Hypoxia - metabolism; Marketability; Metabolism; mutation; persimmon fruit; persimmons; Plant Growth Regulators - metabolism; Plant Proteins - genetics; Plant Proteins - metabolism; postharvest softening; Promoter Regions, Genetic; Regulatory sequences; Shelf life; Signaling; Softening; Tannins - metabolism; Transcription Factors; transcriptional regulation; hypoxia; Astringency removal; transcriptional regulation; ERF; postharvest softening; high CO2; persimmon fruit
• ISSN: 1467-7644; 1467-7652; 1467-7652
• DOI: 10.1111/pbi.12725

Summary Removal of astringency by endogenously formed acetaldehyde, achieved by postharvest anaerobic treatment, is of critical importance for many types of persimmon fruit. Although an anaerobic environment accelerates de‐astringency, it also has the deleterious effect of promoting excessive softening, reducing shelf life and marketability. Some hypoxia‐responsive ethylene response factors (ERFs) participate in anaerobic de‐astringency, but their role in accelerated softening was unclear. Undesirable rapid softening induced by high CO2 (95%) was ameliorated by adding the ethylene inhibitor 1‐MCP (1 μL/L), resulting in reduced astringency while maintaining firmness, suggesting that CO2‐induced softening involves ethylene signalling. Among the hypoxia‐responsive genes, expression of eight involved in fruit cell wall metabolism (Dkβ‐gal1/4, DkEGase1, DkPE1/2, DkPG1, DkXTH9/10) and three ethylene response factor genes (DkERF8/16/19) showed significant correlations with postdeastringency fruit softening. Dual‐luciferase assay indicated that DkERF8/16/19 could trans‐activate the DkXTH9 promoter and this interaction was abolished by a mutation introduced into the C‐repeat/dehydration‐responsive element of the DkXTH9 promoter, supporting the conclusion that these DkERFs bind directly to the DkXTH9 promoter and regulate this gene, which encodes an important cell wall metabolism enzyme. Some hypoxia‐responsive ERF genes are involved in deastringency and softening, and this linkage was uncoupled by 1‐MCP. Fruit of the Japanese cultivar ‘Tonewase’ provide a model for altered anaerobic response, as they lost astringency yet maintained firmness after CO2 treatment without 1‐MCP and changes in cell wall enzymes and ERFs did not occur.