title: An organ-specific role for ethylene in rose petal expansion during dehydration and rehydration.
abstract: Dehydration is a major factor resulting in huge loss from cut flowers during transportation. In the present study, dehydration inhibited petal cell expansion and resulted in irregular flowers in cut roses, mimicking ethylene-treated flowers. Among the five floral organs, dehydration substantially elevated ethylene production in the sepals, whilst rehydration caused rapid and elevated ethylene levels in the gynoecia and sepals. Among the five ethylene biosynthetic enzyme genes (RhACS1-5), expression of RhACS1 and RhACS2 was induced by dehydration and rehydration in the two floral organs. Silencing both RhACS1 and RhACS2 significantly suppressed dehydration- and rehydration-induced ethylene in the sepals and gynoecia. This weakened the inhibitory effect of dehydration on petal cell expansion. β-glucuronidase activity driven by both the RhACS1 and RhACS2 promoters was dramatically induced in the sepals, pistil, and stamens, but not in the petals of transgenic Arabidopsis. This further supports the organ-specific induction of these two genes. Among the five rose ethylene receptor genes (RhETR1-5), expression of RhETR3 was predominantly induced by dehydration and rehydration in the petals. RhETR3 silencing clearly aggravated the inhibitory effect of dehydration on petal cell expansion. However, no significant difference in the effect between RhETR3-silenced flowers and RhETR-genes-silenced flowers was observed. Furthermore, RhETR-genes silencing extensively altered the expression of 21 cell expansion-related downstream genes in response to ethylene. These results suggest that induction of ethylene biosynthesis by dehydration proceeds in an organ-specific manner, indicating that ethylene can function as a mediator in dehydration-caused inhibition of cell expansion in rose petals.
authors.affiliation: Department of Ornamental Horticulture, China Agricultural University, Beijing 100193, PR China.
authors.forename: Daofeng
authors.initials: D
authors.lastname: Liu
authors.forename: Xiaojing
authors.initials: X
authors.lastname: Liu
authors.forename: Yonglu
authors.initials: Y
authors.lastname: Meng
authors.forename: Cuihui
authors.initials: C
authors.lastname: Sun
authors.forename: Hongshu
authors.initials: H
authors.lastname: Tang
authors.forename: Yudong
authors.initials: Y
authors.lastname: Jiang
authors.forename: Muhammad Ali
authors.initials: MA
authors.lastname: Khan
authors.forename: Jingqi
authors.initials: J
authors.lastname: Xue
authors.forename: Nan
authors.initials: N
authors.lastname: Ma
authors.forename: Junping
authors.initials: J
authors.lastname: Gao
mesh_terms: D017360:Arabidopsis / Q000378:metabolism / Q000502:physiology; D003681:Dehydration / Q000378:metabolism; D005030:Ethylenes / Q000032:analysis / Q000378:metabolism*; D035264:Flowers / Q000737:chemistry / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D010940:Plant Proteins / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000378:metabolism / Q000502:physiology; D027826:Rosa / Q000378:metabolism / Q000502:physiology*; D014867:Water / Q000378:metabolism / Q000502:physiology
chemical_list: D005030:Ethylenes; D010940:Plant Proteins; D014867:Water; C036216:ethylene
keywords: cut roses; dehydration; ethylene biosynthesis; ethylene perception; petal expansion; rehydration.