ISHS Acta Horticulturae 543: VII International Symposium on Postharvest Physiology of Ornamental Plants
PHYSIOLOGICAL AND GENETIC REASONS FOR DIFFERENT POSTHARVEST CHARACTERISTICS IN MINIATURE POTTED ROSES |
| Authors: | R. Mueller, A.S. Andersen, M. Serek, B.M. Stummann |
| Keywords: | ethylene, ETR homologs, flower senescence, postharvest, Rosa hybrida |
| Abstract:
Differences in postharvest characteristics of miniature potted roses (Rosa hybrida L.) can partly be explained by differences in endogenous ethylene and/or sensitivity to exogenous ethylene. Comparing cultivars with different postharvest characteristics, dramatic differences in flower longevity of the cultivars 'Bronze' and 'Vanilla' were found, even though both cultivars exhibited a climacteric rise in ethylene production in senescing flowers. Four rose ethylene receptor gene fragments, termed RhETR1-4, were isolated and characterized. RhETR2 (88% amino acid identity to Arabidopsis ETR1) was barely regulated during flower development, but the transcript level differed between the two rose cultivars. RhETR1 (72% amino acid identity to Arabidopsis ERS1) and RhETR3 (67% amino acid identity to Arabidopsis ETR2) exhibited differential expression. Expression of RhETR1 was distinctly higher in the cultivar with short flower life 'Bronze' than in the long lasting cultivar 'Vanilla'. Additionally, modulation of receptor levels was observed during flower development. RhETR3 transcript abundance increased in senescing flowers of ‘Bronze’, while in ‘Vanilla’ this gene appeared to be constitutively expressed at a very low level. Ethylene treatment increased expression of the ethylene receptor genes in flowers of both cultivars, but transcript level differed between the two rose culivars. These results indicate that variation in flower life and ethylene sensitivity among rose cultivars – in ethylene free environment and in response to exogenous ethylene – may be due to differences in receptor levels. | |
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