Development of the Abscission Zone and Morphological Changes of Abscission Cells in the Abscission Process of Persimmon Fruit

Kitajima, Akira; Sasagawa, K.; Hasegawa, K.

doi:10.17660/actahortic.2003.601.10

Cited by 4 publications

(2 citation statements)

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“…Based on the association between LX expression and PCD processes (Lers et al, 1998;Lehmann et al, 2001), we raised the hypothesis that during abscission, PCD, involving LX, occurs and is required for normal progression of abscission (Lers et al, 2006). Previous observations in a variety of plants, including Prunus persica, Chamelaucium uncinatum, Pelargonium 3 Hortorum, and Diospyros kaki, support the hypothesis that cells immediately adjacent to the AZ might lose viability (Evensen et al, 1993;Tirlapur et al, 1995;van Doorn and Stead, 1997;Roberts, 2000;Kitajima et al, 2003;Macnish et al, 2005). We demonstrated the occurrence of PCD by the identification of several hallmarks of the process.…”

Section: Abscission-associated Genes Are Differentially Expressed On mentioning

confidence: 77%

Programmed Cell Death Occurs Asymmetrically during Abscission in Tomato

et al. 2011

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Abscission occurs specifically in the abscission zone (AZ) tissue as a natural stage of plant development. Previously, we observed delay of tomato (Solanum lycopersicum) leaf abscission when the LX ribonuclease (LX) was inhibited. The known association between LX expression and programmed cell death (PCD) suggested involvement of PCD in abscission. In this study, hallmarks of PCD were identified in the tomato leaf and flower AZs during the late stage of abscission. These included loss of cell viability, altered nuclear morphology, DNA fragmentation, elevated levels of reactive oxygen species and enzymatic activities, and expression of PCD-associated genes. Overexpression of antiapoptotic proteins resulted in retarded abscission, indicating PCD requirement. PCD, LX, and nuclease gene expression were visualized primarily in the AZ distal tissue, demonstrating an asymmetry between the two AZ sides. Asymmetric expression was observed for genes associated with cell wall hydrolysis, leading to AZ, or associated with ethylene biosynthesis, which induces abscission. These results suggest that different abscission-related processes occur asymmetrically between the AZ proximal and distal sides. Taken together, our findings identify PCD as a key mechanism that occurs asymmetrically during normal progression of abscission and suggest an important role for LX in this PCD process.

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Section: Abscission-associated Genes Are Differentially Expressed On mentioning

confidence: 77%

Programmed Cell Death Occurs Asymmetrically during Abscission in Tomato

et al. 2011

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“…It was argued that cells that separate must remain metabolically functional or wall loosening would not take place (Beers, 1997;Roberts, 2000). Nevertheless, evidence was accumulating to support the hypothesis that more than a single class of AZ cells might exist and that those cells immediately adjacent to the separation site might lose their viability (Evensen et al, 1993;Tirlapur et al, 1995;van Doorn and Stead, 1997;Roberts, 2000;Kitajima et al, 2003;Macnish et al, 2005).…”

Section: Protein Is Specifically Induced In the Azmentioning

confidence: 99%

Suppression of LX Ribonuclease in Tomato Results in a Delay of Leaf Senescence and Abscission

et al. 2006

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Although present in different organisms and conserved in their protein sequence, the biological functions of T2 ribonucleases (RNase) are generally unknown. Tomato (Lycopersicon esculentum) LX is a T2/S-like RNase and its expression is known to be associated with phosphate starvation, ethylene responses, and senescence and programmed cell death. In this study, LX function was investigated using antisense tomato plants in which the LX protein level was reduced. LX protein levels normally become elevated when leaves senesce and antisense inhibition of LX retarded the progression of senescence. Moreover, we observed a marked delay of leaf abscission in LX-deficient plants. This correlated with specific induction of LX protein in the tomato mature abscission zone tissue. LX RNase gene regulation and the consequences of antisense inhibition indicate that LX has an important functional role in both abscission and senescence.

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