Cell wall metabolism in cold-stored tomato fruit

To extend fruit market life, tomatoes are harvested before red ripe and kept at temperatures below optimum (20°C). In this work, Micro-Tom tomatoes stored at 20°C (normal ripening) were compared with those stored at 15°C or 4°C (chilling injury inducer) for 7 days. In contrast to 4°C, storage at 15°C delayed ripening with the benefit of not enhancing oxidative metabolism and of enabling ripening upon being transferred to 20°C. The transcriptional expression profile of enzymes related to cell wall metabolism was compared at the three temperatures. Although endo-β-1,4-glucanase (Cel1), which is associated with fruit decay, was largely increased after removal from 4°C storage, its expression was not modified in fruits stored at 15°C. Enhanced transcriptional expression of xyloglucan endotransgylcosylase/hydrolases (XTHs) XTH1, –2, –10 and –11, and of two β-xylosidases (Xyl1–2) was detected in fruits stored at 15°C with respect to those at 20°C. Following 2 days at 20°C, these transcripts remained higher in fruits stored at 15°C and XHT3 and –9 also increased. Ethylene evolution was similar in fruits kept at 15°C and 20°C; thus, the changes in the transcript profile and fruit properties between these treatments may be under the control of factors other than ethylene.

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BEL1-LIKE HOMEODOMAIN4 regulates chlorophyll accumulation, chloroplast development, and cell wall metabolism in tomato fruit

Journal of Experimental Botany ◽

10.1093/jxb/eraa272 ◽

2020 ◽

Vol 71 (18) ◽

pp. 5549-5561

Author(s):

Fang Yan ◽

Yushuo Gao ◽

Xiaoqin Pang ◽

Xin Xu ◽

Ning Zhu ◽

...

Keyword(s):

Cell Wall ◽

Chloroplast Development ◽

Binding Protein ◽

Tomato Fruit ◽

Regulation Mechanism ◽

Cell Wall Metabolism ◽

Chlorophyll Metabolism ◽

Magnesium Chelatase ◽

Chlorophyll Accumulation ◽

Tomato Fruit Ripening

Abstract Tomato (Solanum lycopersicum) is a model plant for studying fruit development and ripening. In this study, we found that down-regulation of a tomato bell-like homeodomain 4 (SlBL4) resulted in a slightly darker-green fruit phenotype and increased accumulation of starch, fructose, and glucose. Analysis of chlorophyll content and TEM observations was consistent with these phenotypes, indicating that SlBL4 was involved in chlorophyll accumulation and chloroplast formation. Ripened fruit of SlBL4-RNAi plants had noticeably decreased firmness, larger intercellular spaces, and thinner cell walls than the wild-type. RNA-seq identified differentially expressed genes involved in chlorophyll metabolism, chloroplast development, cell wall metabolism, and carotenoid metabolism. ChIP-seq identified (G/A) GCCCA (A/T/C) and (C/A/T) (C/A/T) AAAAA (G/A/T) (G/A) motifs. SlBL4 directly inhibited the expression of protoporphyrinogen oxidase (SlPPO), magnesium chelatase H subunit (SlCHLD), pectinesterase (SlPE), protochlorophyllide reductase (SlPOR), chlorophyll a/b binding protein 3B (SlCAB-3B), and homeobox protein knotted 2 (TKN2). In contrast, it positively regulated the expression of squamosa promoter binding protein-like colorless non-ripening (LeSPL-CNR). Our results indicate that SlBL4 is involved in chlorophyll accumulation, chloroplast development, cell wall metabolism, and the accumulation of carotenoids during tomato fruit ripening, and provide new insights for the transcriptional regulation mechanism of BELL-mediated fruit growth and ripening.

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Apoplastic pH and inorganic ion levels in tomato fruit: A potential means for regulation of cell wall metabolism during ripening

Physiologia Plantarum ◽

10.1034/j.1399-3054.1999.105316.x ◽

1999 ◽

Vol 105 (3) ◽

pp. 506-512 ◽

Cited By ~ 91

Author(s):

Domingos P. F. Almeida ◽

Donald J. Huber

Keyword(s):

Cell Wall ◽

Tomato Fruit ◽

Cell Wall Metabolism ◽

Apoplastic Ph ◽

Inorganic Ion

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Tomato SlBL4 plays an important role in fruit pedicel organogenesis and abscission

Horticulture Research ◽

10.1038/s41438-021-00515-0 ◽

2021 ◽

Vol 8 (1) ◽

Author(s):

Fang Yan ◽

Zhehao Gong ◽

Guojian Hu ◽

Xuesong Ma ◽

Runyao Bai ◽

...

Keyword(s):

Cell Wall ◽

Tomato Fruit ◽

Abscission Zone ◽

Luciferase Reporter ◽

Rna Seq ◽

Cell Wall Metabolism ◽

Cell Layers ◽

A Cell ◽

Important Trait ◽

Signaling Components

AbstractAbscission, a cell separation process, is an important trait that influences grain and fruit yield. We previously reported that BEL1-LIKE HOMEODOMAIN 4 (SlBL4) is involved in chloroplast development and cell wall metabolism in tomato fruit. In the present study, we showed that silencing SlBL4 resulted in the enlargement and pre-abscission of the tomato (Solanum lycopersicum cv. Micro-TOM) fruit pedicel. The anatomic analysis showed the presence of more epidermal cell layers and no obvious abscission zone (AZ) in the SlBL4 RNAi lines compared with the wild-type plants. RNA-seq analysis indicated that the regulation of abscission by SlBL4 was associated with the altered abundance of genes related to key meristems, auxin transporters, signaling components, and cell wall metabolism. Furthermore, SlBL4 positively affected the auxin concentration in the abscission zone. A dual-luciferase reporter assay revealed that SlBL4 activated the transcription of the JOINTLESS, OVATE, PIN1, and LAX3 genes. We reported a novel function of SlBL4, which plays key roles in fruit pedicel organogenesis and abscission in tomatoes.

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