|Authors: ||N. Ahmadi, H. Mibus, M. Serek|
|Keywords: ||abscission process, CTR, ETR, F1 progeny, laccase, RhLAC|
The ethylene-induced organ abscission in miniature roses F1 progenies was evaluated and characterized in this study.
The expression of two ethylene receptor genes (RhETR1, RhETR3), and the signal transduction pathway (RhCTR1 and RhCTR2) were investigated by qRT-PCR in ethylene-sensitive and ethylene-tolerant rose genotypes in response to ethylene treatment.
From population of 233 F1 genotypes, two sensitive and three resistant genotypes were selected, based on the ethylene-induced leaf and flower bud abscission.
Chlorophyll degradation and leaf chroma value significantly increased in sensitive genotypes compared to resistant genotypes when treated with ethylene for one week.
After fortnight exposure to ethylene, chroma value was not changed but chlorophyll content declined in two ethylene-tolerant genotypes.
The relative expression of RhETR1 increased after 3 days of ethylene treatment in pedicels and petioles of one out of two ethylene tolerant genotypes.
In petioles of this genotype, the expression of RhCTR1 was high too.
The results indicated that exogenous-ethylene treatment did not influence the expression pattern of RhETR3 and RhCTR2 genes, neither in sensitive nor in tolerant genotypes.The expression of recently isolated gene, laccase, was also evaluated after 3 days of ethylene treatment.
The ethylene-induced RhLAC transcript showed a higher accumulation pattern in abscission zones of pedicels and petioles in ethylene sensitive genotypes than in tolerant genotypes.
Based on this evidence, the expression of RhETR1, RhETR3, RhCTR1 and RhCTR2 was shown to be dependent on genotype.
In contrast, highly increasing expression of Laccase transcript under ethylene treatment in sensitive genotypes is hypothesized to be related to the abscission process.
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