Comparison on the Development of Abscission Zones in the Pedicels between Two Tomato Cultivars.

Tabuchi, Toshihito

doi:10.2503/jjshs.68.993

Cited by 12 publications

(8 citation statements)

References 14 publications

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“…AZ cells of a tomato flower are recognized even at the early stage of flower primordium development; at the flower anthesis stage, six to eight layers of cells are observed in the AZ and the flower pedicels have acquired the competence to respond to abscission-promoting signals [27,33,34]. To identify genes preferentially expressed in the AZ of tomato flower pedicels at anthesis, we used the Agilent tomato 44K oligonucleotide DNA microarray to perform transcriptome assays comparing AZs and the non-AZ pedicel regions, Dis and Prox (Figure 1A).…”

Section: Resultsmentioning

confidence: 99%

“…If so, how does this common regulation act on these dissimilar tissues and what cell activities does it regulate? Observations of pedicel AZs showed that small cells with densely packed cytoplasm are arranged within AZs [34,80] and these cells are assumed to be maintained in an undifferentiated state [3]. Therefore, one plausible explanation is that the common regulatory system in pedicel AZs and SAMs may serve to maintain small, undifferentiated cells in both tissues.…”

Section: Discussionmentioning

confidence: 99%

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Expression profiling of tomato pre-abscission pedicels provides insights into abscission zone properties including competence to respond to abscission signals

et al. 2013

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BackgroundDetachment of plant organs occurs in abscission zones (AZs). During plant growth, the AZ forms, but does not develop further until the cells perceive abscission-promoting signals and initiate detachment. Upon signal perception, abscission initiates immediately; if there is no signal, abscission is not induced and the organ remains attached to the plant. However, little attention has been paid to the genes that maintain competence to respond to the abscission signal in the pre-abscission AZ. Recently, we found that the tomato (Solanum lycopersicum) transcription factors BLIND (Bl), GOBLET (GOB), Lateral suppressor (Ls) and a tomato WUSCHEL homologue (LeWUS) are expressed specifically in pre-abscission tissue, the anthesis pedicel AZs. To advance our understanding of abscission, here we profiled genome-wide gene expression in tomato flower pedicels at the pre-abscission stage.ResultsWe examined the transcriptomes of three tomato flower pedicel regions, the AZ and flanking proximal- (Prox) and distal- (Dis) regions, and identified 89 genes that were preferentially expressed in the AZ compared to both Prox and Dis. These genes included several transcription factors that regulate apical or axillary shoot meristem activity. Also, genes associated with auxin activity were regulated in a Prox-Dis region-specific manner, suggesting that a gradient of auxin exists in the pedicel. A MADS-box gene affecting floral transition was preferentially expressed in the Prox region and other MADS-box genes for floral organ identification were preferentially expressed in Dis, implying that the morphologically similar Prox and Dis regions have distinct identities. We also analyzed the expression of known regulators; in anthesis pedicels, Bl, GOB, Ls and LeWUS were expressed in the vascular cells of the AZ region. However, after an abscission signal, Bl was up-regulated, but GOB, Ls and LeWUS were down-regulated, suggesting that Bl may be a positive regulator of abscission, but the others may be negative regulators.ConclusionsThis study reveals region-specific gene expression in tomato flower pedicels at anthesis and identifies factors that may determine the physiological properties of the pre-abscission pedicel. The region-specific transcriptional regulators and genes for auxin activity identified here may prevent flower abscission in the absence of signal or establish competence to respond to the abscission signal.

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Expression profiling of tomato pre-abscission pedicels provides insights into abscission zone properties including competence to respond to abscission signals

et al. 2013

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“…This band of cells, which is formed on a disc across the basal end of the abscission organ connection, is defined as the ab-scission layer (Gawadi and Avery, 1950). In the tomato, the abscission layer, which is composed of several layers of small cells, expands from the central parenchyma region to the cortical region in the flower pedicel (Tabuchi, 1999), and in the fruit pedicel at a full ripe stage (Tabuchi et al, 2000). This was also observed for the potato flower pedicel (Tabuchi, 1998).…”

Section: Introductionmentioning

confidence: 75%

“…It is generally considered that formation of an abscission layer is involved in leaf abscission in poinsettia, cotton, and pepper (Gawadi and Avery, 1950). The formation of an abscission layer was observed in the common tomato flower pedicel (Tabuchi, 1999), which was composed of 6-8 layers of small cells at anthesis. In Japanese persimmon, the abscission layer was composed of about seven layers of small cells, and was observed from the epidermis region to the outside of the vascular bundle region at the junction between the calyx and peduncle at least two weeks before anthesis (Kitajima, 2000).…”

Section: Discussionmentioning

confidence: 99%

Anatomical Observations of the Citrus Fruit Abscission Zone and Morphological Changes of the Cells during Secondary Physiological Fruit Drop

Kitajima

Kataoka

et al. 2017

Hortic J

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Histological investigations of the fruit abscission zone and morphological changes in abscission zone cells in ponkan (C. reticulata Blanco), hyuganatsu (C. tamurana hort. ex Tanaka), 'Kiyomi' (C. unshiu × C. sinensis (L.) Osbeck), and satsuma mandarin (Citrus unshiu Marcow.) were conducted using detached fruits incubated in agar medium under 25°C, 4 weeks after anthesis during secondary physiological fruit drop. In the 96 h after the fruit abscission induction by detaching the fruits, the cumulative abscission ratio was 100% in ponkan, 22% in 'Kiyomi', and below 10% in hyuganatsu and satsuma mandarin. Fruit abscission began at 36 h in ponkan and 'Kiyomi', at 54 h in satsuma mandarin, and at 60 h in hyuganatsu after the fruit detachment. The fruit abscission zone was located on the connected part between the fruit and the disc in ponkan and hyuganatsu on the disc tissue in satsuma mandarin and 'Kiyomi'. During the fruit abscission process, no abscission layer was observed at the abscission zone in these species and cultivars. Morphological changes in the abscission zone cells were determined by scoring cell changes (a score from 0 to 4) at five positions of the abscission zone. In ponkan, the morphological changes in the abscission zone cells, which began 30 h after fruit abscission induction, were synchronized in a symmetrical position in the abscission zone. The changes in 'Kiyomi' began at 30 h, and they consisted of a one sided collapse of the symmetrical position of the abscission zone. The changes in satsuma mandarin were similar to those in 'Kiyomi'. This implies that the different patterns of morphological changes in the abscission zone cells in ponkan, 'Kiyomi', and satsuma mandarin depend on the different locations of their abscission zones. Overall, the results suggest that the cue for fruit abscission in early abscised fruit occurs until 30 h after blocking the carbohydrate translocation to the fruit under 25°C.Key Words: abscission induction, abscission layer, cue of fruit abscission, fruit abscission ratio, score of cell changing level.

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“…Tomato is a very convenient model system, since tomato plants develop a distinct AZ in the midpoint of the flower pedicel, referred to as a pedicel AZ or FAZ in different publications. The anatomy and development of the tomato FAZ is well established [165][166][167], as are the proteins involved in the regulation of the FAZ differentiation and development [168][169][170][171][172][173]. Since the eighties of the previous century, in -depth studies have defined enzymes involved in cell separation in various species.…”

Section: Elucidation Of the Sequence Of Events Leading To Organ Abscimentioning

confidence: 99%

Role of auxin depletion in abscission control

2015

Stewart Postharvest Review

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Purpose of review:Abscission is a programmed developmental process initiated by auxin depletion. This review summarizes the mechanisms leading to auxin depletion in the abscission zone (AZ), evaluates the methods for estimation of the spatio-temporal auxin levels, demonstrates how auxin depletion occurs during natural, stressinduced, and artificially-induced organ abscission, and presents new evidence for early and late events resulting from auxin depletion which lead to organ abscission. Findings: Auxin depletion occurs during natural developmental processes which end in organ abscission (leaf and flower senescence, fruit ripening, and self-pruning) and stress-induced abscission, and following artificial organ removal in the tomato model system. Stress-induced auxin depletion is mediated by increased ethylene and reactive oxygen species (ROS) production and carbohydrate starvation. Similar changes in auxin-related genes occurred in both flower AZ (FAZ) and leaf AZ (LAZ) following flower or leaf removal, respectively, suggesting a similar regulation of the abscission process of these organs. Auxin depletion resulted from decreased indole-3acetic acid (IAA) biosynthesis and transport, as well as from enhanced IAA transport autoinhibition (ATA), conjugation and oxidative IAA catabolism. Functional analyses of several target genes delaying abscission, such as Knotted-Like Homeobox Protein1 (KD1), Tomato Proline Rich Protein (TPRP), Ethylene Responsive Factor52 (ERF52), and Ribonuclease LX (LX), shed light on various events operating in response to auxin depletion in tomato FAZ and/or LAZ. The information gained allows a better understanding of the abscission process driven by auxin depletion, and might lead to development of improved methods for abscission control in horticultural crops. Direction for future research: A better understanding of abscission regulation as it pertains to auxin depletion will require advanced molecular tools such as microarrays, new generation sequencing (NGS), transcriptomic, functional, and proteomic analyses of target genes and proteins found to operate in the abscission process.

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Comparison on the Development of Abscission Zones in the Pedicels between Two Tomato Cultivars.

Cited by 12 publications

References 14 publications

Expression profiling of tomato pre-abscission pedicels provides insights into abscission zone properties including competence to respond to abscission signals

Expression profiling of tomato pre-abscission pedicels provides insights into abscission zone properties including competence to respond to abscission signals

Anatomical Observations of the Citrus Fruit Abscission Zone and Morphological Changes of the Cells during Secondary Physiological Fruit Drop

Role of auxin depletion in abscission control

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