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Cold perception and gene expression differ in Olea europaea seed coat and embryo during drupe cold acclimation
Author(s) -
D'Angeli S.,
Falasca G.,
Matteucci M.,
Altamura M. M.
Publication year - 2013
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.2012.04372.x
Subject(s) - endosperm , coat , biology , embryo , botany , olea , microbiology and biotechnology , biochemistry , horticulture , paleontology
SummaryFAD 2 and FAD 7 desaturases are involved in cold acclimation of olive ( Olea europaea ) mesocarp. There is no research information available on cold acclimation of seeds during mesocarp cold acclimation or on differences in the cold response of the seed coat and embryo. How FAD 2 and FAD 7 affect seed coat and embryo cold responses is unknown. Osmotin positively affects cold acclimation in olive tree vegetative organs, but its role in the seeds requires investigation. Oe FAD 2.1 , Oe FAD 2.2 , Oe FAD 7 and Oeosmotin were investigated before and after mesocarp acclimation by transcriptomic, lipidomic and immunolabelling analyses, and cytosolic calcium concentration ([Ca 2+ ] cyt ) signalling, F‐actin changes and seed development were investigated by epifluorescence/histological analyses. Transient [Ca 2+ ] cyt rises and F‐actin disassembly were found in cold‐shocked protoplasts from the seed coat, but not from the embryo. The thickness of the outer endosperm cuticle increased during drupe exposure to lowering of temperature, whereas the embryo protoderm always lacked cuticle. Oe FAD 2 transcription increased in both the embryo and seed coat in the cold‐acclimated drupe, but linoleic acid (i.e. the product of FAD 2 activity) increased solely in the seed coat. Osmotin was immunodetected in the seed coat and endosperm of the cold‐acclimated drupe, and not in the embryo. The results show cold responsiveness in the seed coat and cold tolerance in the embryo. We propose a role for the seed coat in maintaining embryo cold tolerance by increasing endosperm cutinization through FAD 2 and osmotin activities.