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Glucosinolate‐accumulating S‐cells in Arabidopsis leaves and flower stalks undergo programmed cell death at early stages of differentiation
Author(s) -
Koroleva Olga A.,
Gibson Trevor M.,
Cramer Rainer,
Stain Chris
Publication year - 2010
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/j.1365-313x.2010.04339.x
Subject(s) - biology , meristem , phloem , arabidopsis , programmed cell death , endodermis , stalk , plant cell , microbiology and biotechnology , botany , organelle , apoptosis , glucosinolate , cell wall , shoot , biochemistry , gene , mutant , brassica , horticulture
Summary The plant secondary metabolites glucosinolates (GSL) have important functions in plant resistance to herbivores and pathogens. We identified all major GSL that accumulated in S‐cells in Arabidopsis by MALDI‐TOF MS, and estimated by LC‐MS that the total GSL concentration in these cells is >130 m m . The precise locations of the S‐cells outside phloem bundles in rosette and cauline leaves and in flower stalks were visualised using sulphur mapping by cryo‐SEM/energy‐dispersive X‐ray analysis. S‐cells contain up to 40% of the total sulphur in flower stalk tissues. S‐cells in emerging flower stalks and developing leaf tissues show typical signs of programmed cell death (PCD) or apoptosis, such as chromatin condensation in the nucleus and blebbing of the membranes. TUNEL staining for DNA double‐strand breaks confirmed the occurrence of PCD in S‐cells in post‐meristematic tissues in the flower stalk as well as in the leaf. Our results indicate that S‐cells in post‐meristematic tissues show an extreme degree of metabolic specialisation in addition to PCD. Accumulation and maintenance of a high concentration of GSL in these cells are accompanied by degradation of a number of cell organelles. The substantial changes in cell composition during S‐cell differentiation indicate the importance of this particular GSL‐based phloem defence system. The specific anatomy of the S‐cells and the ability to accumulate specialised secondary metabolites is similar to that of the non‐articulated laticifer cells in latex plants, suggesting a common evolutionary origin.