Regulation of Ethylene Biosynthesis by Phytohormones in Etiolated Rice (Oryza sativa L.) Seedlings

이한용,윤경미 한국분자세포생물학회 2018 Molecules and cells Vol.41 No.4

The gaseous hormone ethylene influences many aspects of plant growth, development, and responses to a variety of stresses. The biosynthesis of ethylene is tightly regulated by various internal and external stimuli, and the primary target of the regulation is the enzyme 1-aminocyclopropane-1-carboxylic acid (ACC) synthase (ACS), which catalyzes the rate-limiting step of ethylene biosynthesis. We have previously demonstrated that the regulation of ethylene biosynthesis is a common feature of most of the phytohormones in etiolated Arabidopsis seedlings via the modulation of the protein stability of ACS. Here, we show that various phytohormones also regulate ethylene biosynthesis from etiolated rice seedlings in a similar manner to those in Arabidopsis. Cytokinin, brassinosteroids, and gibberellic acid increase ethylene biosynthesis without changing the transcript levels of neither OsACS nor ACC oxidases (OsACO), a family of enzymes catalyzing the final step of the ethylene biosynthetic pathway. Likewise, salicylic acid and abscisic acid do not alter the gene expression of OsACS, but both hormones downregulate the transcript levels of a subset of ACO genes, resulting in a decrease in ethylene biosynthesis. In addition, we show that the treatment of the phytohormones results in distinct etiolated seedling phenotypes, some of which resemble ethylene-responsive phenotypes, while others display ethylene-independent morphologies, indicating a complicated hormone crosstalk in rice. Together, our study brings a new insight into crosstalk between ethylene biosynthesis and other phytohormones, and provides evidence that rice ethylene biosynthesis could be regulated by the post-transcriptional regulation of ACS proteins.

옥수수 종자의 발육 중 ethylene 발생과 내부형태 변화

이석순,서정문,홍승범 韓國作物學會 2006 Korean journal of crop science Vol.51 No.5

옥수수의 종자발육에 ethylene이 미치는 영향을 알기 위하여 마치종, 단옥수수, 초당옥수의 배와 배유의 발육과 ethylene 발생을 조사하였다. 그리고 초당옥수수에 ethylene 발생과 작용을 조절하는 aminoethoxyvinyl glycine(AVG), silver thiosulfate(STS), ethephon(2-chloroethylphosphonic acid, CEPA)를 출사 후 9 및 21일에 전 식물체와 포엽에 처리하여 ethylene 발생양상과 배와 배유의 발육을 조사하여 채종 시 종자발달을 촉진할 수 있는 방법을 찾고자 하였으며, 그 결과를 요약하면 다음과 같다. 1. 마치종은 배와 배유 모두 출사 후 56일까지 건물중이 증가하였다. 그러나 단옥수수와 초당옥수수의 배는 출사 후 각각 56일 및 49일까지, 배유는 출사 후 35일 및 28일까지 증가하였다. 2. 종자의 ethylene 발생량은 초당옥수수가 단옥수수나 마치종보다 많았다. 3. 배유조직의 변화는 출사 후 21일부터 배의 끝 부분에서 동공이 생기기 시작하여 마치종은 동공이 유지되나 단옥수수는 출수 후 42일에는 동공이 붕괴되었고, 초당옥수수는 배 위쪽 및 옆쪽까지 동공이 생겼다가 수축되었다. 4. 초당옥수수 품종 Xtrasweet 82에서 AVG와 STS는 ethylene 발생량을 감소시키고 100립중을 다소 증가시켰으나, CEPA는 ethylene 발생량을 증가시키고 100립중을 감소 시키는 경향이었다. 5. CEPA 처리는 배유에 동공이 발생하는 시기가 다소 빨랐으나 AVG와 STS 처리는 큰 효과가 없었다. In order to investigate the effects of ethylene on the seed development of three corn types (dent, sweet, and super sweet corns), aminoethoxyvinyl glycine (AVG) and silver thiosulfate (STS) and ethephon (2-chloroethylphosphonic acid, CEPA) were applied either on whole plants or shanks of ears at 9 and 21 days after silking. Ethylene production of developing super sweet corn seeds was much higher than those of sweet and dent corns. The cavity in the endosperm tissues of the super sweet corn started earlier and endosperm was collapsed more severely compared to those of sweet and dent corns. Ethylene production seemed to be related to the death of endosperm cells to form a cavity. Application of AVG and STS reduced ethylene production and delayed cavity formation in endosperm of super sweet corn seeds, while CEPA increased ethylene production and enhanced the time of cavity formation. AVG and STS increased 100-seed weight, while CEPA decreased.

Ethylene-driven expression of genes involved in carotenoid biosynthesis during postharvest ripening is different in creole and commercial Carica papaya L. fruits

Chan-León Arianna C.,Estrella-Maldonado Humberto,Fuentes-Ortiz Gabriela,Torres Luis,Sánchez Sergio Peraza,Santamaría Jorge M. 한국원예학회 2024 Horticulture, Environment, and Biotechnology Vol.65 No.2

This paper reports ethylene production, expression levels of ethylene precursor’s genes, as well as carotenoid content and expression levels of carotenoid biosynthesis genes, during postharvest ripening of three diff erent papaya genotypes of contrasting origin (2 creoles and 1 commercial) and pulp color (yellow, orange and red), under conditions that promote ethylene formation and under those inhibiting ethylene. Our study showed that naturally ripened papaya fruits presented relatively high ethylene production levels that was correlated with changes in expression levels of both ethylene pre cursor’s genes (CpACCs1, CpACCs2, CpACCo1 and CpACCo2), and carotenoid biosynthesis genes (CpPSY, CpZDS, CpLCY-β2, CpCHX-β). However, when papaya fruits were treated with an ethylene inducer (Ethephon; 2.5 g L − 1 of 2-chloroethyl-phosphonic acid) fruits ripened faster (two days earlier than controls), and they also showed a higher ethyl ene peak and higher expression levels of both ethylene precursors genes and carotenoid biosynthesis genes, than control fruits. In contrast, papaya fruits treated with an ethylene inhibitor (1-MCP; 300 nL L − 1 of 1-methylcyclopropene) never ripened (in fact they did not show changes in fruit fi rmness, °Brix, pH or acidity), and they showed very low ethylene production and low expression levels of ethylene precursors genes, as well as showing low expression of carotenogenic genes, throughout the postharvest ripening process. Correlation analysis showed that increased ethylene production was highly correlated with increased expression of both ethylene precursors genes and carotenoids biosynthesis genes, but the specifi c carotenogenic genes induced by ethylene diff ered among commercial and creole papaya genotypes.

Ethylene Biosynthesis, Signaling, and Regulation in Roses

Suong Tuyet Thi Ha,Byung-Chun In 한국화훼학회 2021 화훼연구 Vol.29 No.1

Ethylene-mediated premature floral senescence influences the postharvest quality and longevity of rose flowers. In recent years, studies have unveiled the action of ethylene during the development and senescence of rose flowers. However, despite the evidence that ethylene is highly produced in ethylene-sensitive roses, there is not always a direct interrelationship between ethylene sensitivity and rose flower longevity. In addition, ethylene sensitivity and ethylene-related gene expressions in roses are still not clearly understood. In this review, we summarized and discussed ethylene synthesis and sensitivity, role of ethylene-related genes, and impacts of ethylene on the postharvest quality of cut roses. By combining the mechanism of ethylene biosynthesis and signaling with ethylene sensitivity, we also highlighted the potential use of ethylene inhibitors for ethylene control and to improve the postharvest quality of cut rose flowers. We believe that this review will provide sufficient information about ethylene biology in rose flowers and contribute in developing effective methods to extend the postharvest life of roses by preventing ethylene damage.

Relationships between the longevity, water relations, ethylene sensitivity, and gene expression of cut roses

In, B.C.,Ha, S.T.T.,Lee, Y.S.,Lim, J.H. Elsevier 2017 Postharvest biology and technology Vol.131 No.-

<P>Cut roses (Rosa hybrida L.) have been classified as ethylene-sensitive, but the nature of the ethylene sensitivity changes in these flowers has not been well characterized. In the present study, the relationships between vase life, ethylene sensitivity, and expression of ethylene biosynthetic genes were determined in 33 cultivars. Despite the same growing season and identical postharvest environments, the vase life of cultivars ranged from 5.5 to 15.5 d. Ethylene primarily accelerated petal wilting, which is the main factor shortening the longevity in long vase life cultivars. qRT-PCR analysis revealed that among five ethylene synthesis genes, RhACO1 showed the most distinct expression patterns in response to ethylene. ACS genes were differentially expressed in response to ethylene, and only RhACS2 and RhACS4 are induced by ethylene and during flower senescence. Correlation analysis revealed that the major factors that terminate vase life vary depending on flower sensitivity to ethylene. The vase life of ethylene-sensitive cultivars was strongly related to RhACO1 transcript level, which was induced by ethylene exposure. In contrast, the vase life of ethylene-insensitive cultivars was mostly reduced due to an early failure of water relations, as a consequence of the decreased hydraulic conductance of stems and water loss via transpiration. The current study revealed that postharvest treatments to improve the vase life should be differently applied based on the ethylene sensitivity of each cultivar.</P>

참다래 품종별 저장 온도와 에틸렌 처리에 따른 품질 변화

최한률 ( Han-ryul Choi ),권혁 ( Hyok Kwon ),시멜레스틸라훈 ( Shimeles Tilahun ),백민우 ( Min-woo Baek ),이희철 ( Hee-cheol Lee ),박도수 ( Do-su Park ),안기석 ( Ki-seok An ),정천순 ( Cheon-soon Jeong ) 강원대학교 농업생명과학연구원(구 농업과학연구소) 2021 강원 농업생명환경연구 Vol.33 No.2

본 연구는 ‘Hayward’(그린), ‘Haeguem’(골드) 및 ‘Hongyang’(레드) 참다래의 품종별 과실의 후숙 특성, 온도(10℃, 25℃) 및 에틸렌 농도별(50 ppm, 100 ppm) 처리에 따른 참다래의 품질 변화를 분석한 연구결과는 다음과 같다. 세 품종 모두 후숙 기간이 길어짐에 따라 경도와 산도가 점차 감소하고, 당도와 당산비가 증가하는 경향을 나타내었다. 경도는 저장 25℃ 에틸렌 처리구(50 ppm, 100 ppm)의 경우 ‘Haeguem’ 및 ‘Hongyang’은 후숙 2일차에 각각 3.94-4.61 N, 4.94-5.00 N, ‘Hayward’는 후숙 4일차 5.67-7.57 N으로 소비자의 선호도 범위(2-8 N)를 충족하였다. 저장 10℃ ‘Hayward’의 경우 대조구와 에틸렌 처리구 사이에 유의적인 차이가 나타나지 않았으며, 저장 기간 동안 품질을 효과적으로 유지하였다. 당도의 경우 세 품종 모두 저장 온도와 에틸렌 처리 상관없이 후숙 기간이 길어짐에 따라 증가하는 경향을 나타내었으며, 저장 25℃ 모든 후숙 기간 동안 대조구와 에틸렌 처리구 사이에 유의적인 차이를 나타내었다. 적정 산도는 다른 품종들과 비교하였을 때 ‘Hayward’ 에틸렌 처리구에서 가장 큰 효과를 보였다. 저장 25℃ ‘Hayward’ 후숙 6일차에 대조구, 에틸렌 50 ppm 처리구의 적정 산도는 각각 1.53, 0.31 mg/100g^-1로 두 처리구 사이에 1.22 mg/100g^-1라는 큰 차이를 나타내었다. 이와는 다르게 저장 10℃ ‘Hayward’와 ‘Haeguem’에서 대조구와 에틸렌 처리구 사이에 유의적인 차이는 나타나지 않았다. 당산비는 세 품종 모두 후숙 기간이 길어짐에 따라 증가하는 경향을 보였다. 특히 저장 25℃ 후숙 6일차에 ‘Hayward’와 ‘Haeguem’의 에틸렌 처리구에서 값이 각각 35.2, 44.3으로 높은 값을 나타내었다. 그리고 경도, 당도, 산도는 당산비 사이에 높은 유의적 상관관계(r = -0.54, 0.65, -0.83)를 나타내었다. 저장 온도 10℃에서 25℃보다 에틸렌 처리에 따른 효과가 적었는데, 이는 저온 에서 참다래의 신진대사가 느려지면서 에틸렌 처리의 효과가 줄어든 것으로 판단된다. 또한 에틸렌 처리 농도에 대한 품질의 유의적 차이는 나타나지 않았다. 이는 과실의 숙성이 시작되어 내부 에틸렌 농도가 포화 수준으로 증가하고 나면 외부 에틸렌이 숙성 과정에 더 이상 영향을 미치기 어렵기 때문으로 판단된다. 이상의 결과를 종합해보면 경도, 당도, 산도, 당산비를 기준으로 ‘Hayward’의 경우 10℃ 에서 6일차까지 소비자 선호도에 충족되지 않았으나, 25℃ 조건 에틸렌 처리 후 4일차부터 소비자 선호도가 충족되었다. ‘Haeguem’ 및 ‘Hongyang’의 경우 10℃, 25℃ 조건에서 모두 에틸렌 처리 후 2일차부터 소비자 선호도가 충족되는 것을 확인하였다. In this study, green ‘Hayward’, gold ‘Haegeum’, and red ‘Hongyang’ kiwifruit cultivars were treated with 50 and 100 ppm ethylene in commercial packing boxes to investigate the postharvest ripening quality during the storage at 10℃ and 25℃. As the ripening period proceeded, all three cultivars showed a gradual decreasing trend in firmness and titratable acidity (TA), whereas total soluble solids (TSS) content and Brix acid ratio (BAR) showed an increasing trend. In the case of storage at 25℃, the firmness of ‘Haegeum’ and ‘Hongyang’ ranged from 3.94 to 4.61 N and 4.94 to 5.00 N on the 2nd day at 50 and 100 ppm ethylene, respectively. However, ‘Hayward’ maintained firmness (5.67-7.57 N) up to the 4th day of ripening. In the case of storage at 10℃, there was no significant difference between the control and ethylene treatments. Regarding TSS, all three cultivars showed increasing trends as the ripening period increased, regardless of storage temperature and ethylene concentration, and there was a significant difference between the control and ethylene-treated groups throughout the ripening period at 25℃. The TA of ‘Hayward’ showed the largest difference between the control and treatment as compared to ‘Haegeum’ and ‘Hongyang’ at 25℃. On the 6th day of ripening, the TA of ‘Hayward’ was 1.53 and 0.31 mg/100 g^-1 in the control and 50 ppm ethylene treatment, respectively. In contrast, there was no significant difference between the control and ethylene treatments in ‘Hayward’ and ‘Haegeum’ at 10℃. The BAR showed increasing trends in all three cultivars as the ripening period increased. In particular, ethylene-treated ‘Hayward’ and ‘Haegeum’ showed high BAR values of 35.2 and 44.3, respectively, on the 6 th day a t 25℃. In addition, firmness, TSS, and TA showed signific ant correlations (r = -0.54, 0.65, and -0.83, respectively) with BAR. Generally, the effect of ethylene treatment at 10℃ was less than at 25℃, which may be due to the low metabolic rates of the fruits at low temperatures. In addition, there was no significant difference in quality with the change in ethylene concentration because the external ethylene could no longer influence the ripening process once fruit ripening was initiated and the internal ethylene concentration reached saturation levels. Taken together, based on firmness, TSS, TA, and BAR, consumers’ preferences for ‘Hayward’ were not met at 10℃ until the 6th day of ripening, but at 25℃, consumers’ preferences were attained after the 4th day. In the case of ‘Haegeum’ and ‘Hongyang’, consumers’ preferences were attained starting from the 2nd day of ethylene treatment in both 10℃ and 25℃ conditions.

Regulation of Ethylene Biosynthesis by Phytohormones in Etiolated Rice (Oryza sativa L.) Seedlings

Lee, Han Yong,Yoon, Gyeong Mee Korean Society for Molecular and Cellular Biology 2018 Molecules and cells Vol.41 No.4

The gaseous hormone ethylene influences many aspects of plant growth, development, and responses to a variety of stresses. The biosynthesis of ethylene is tightly regulated by various internal and external stimuli, and the primary target of the regulation is the enzyme 1-aminocyclopropane-1-carboxylic acid (ACC) synthase (ACS), which catalyzes the rate-limiting step of ethylene biosynthesis. We have previously demonstrated that the regulation of ethylene biosynthesis is a common feature of most of the phytohormones in etiolated Arabidopsis seedlings via the modulation of the protein stability of ACS. Here, we show that various phytohormones also regulate ethylene biosynthesis from etiolated rice seedlings in a similar manner to those in Arabidopsis. Cytokinin, brassinosteroids, and gibberellic acid increase ethylene biosynthesis without changing the transcript levels of neither OsACS nor ACC oxidases (OsACO), a family of enzymes catalyzing the final step of the ethylene biosynthetic pathway. Likewise, salicylic acid and abscisic acid do not alter the gene expression of OsACS, but both hormones downregulate the transcript levels of a subset of ACO genes, resulting in a decrease in ethylene biosynthesis. In addition, we show that the treatment of the phytohormones results in distinct etiolated seedling phenotypes, some of which resemble ethylene-responsive phenotypes, while others display ethylene-independent morphologies, indicating a complicated hormone crosstalk in rice. Together, our study brings a new insight into crosstalk between ethylene biosynthesis and other phytohormones, and provides evidence that rice ethylene biosynthesis could be regulated by the post-transcriptional regulation of ACS proteins.

Poly(ethylene-co-octene) - Ethylene - 1-Octene 3성분계 혼합물의 상거동

손진언 ( Jin Eun Sohn ),정성윤 ( Sung Yoon Chung ),한상훈 ( Sang Hoon Han ),이상호 ( Sang Ho Lee ) 한국고무학회 2006 엘라스토머 및 콤포지트 Vol.41 No.2

Poly(ethylene-co-15.3 mole% octene) (PEO(15)) - 1-옥텐 2성분계 혼합물과 PEO(15)와 (에틸렌+ l-옥텐) 혼합용매로 이루어진 3성분계 혼합물의 상거동을 160℃와 1,000 bar의 영역까지 측정하였다. PEO(15) - 에틸렌 - 1-옥텐 혼합물에서 에틸렌의 함량이 증가함에 따라 cloud-point 곡선이 측정되는 압력이 급격하게 높아졌다. 에틸렌 함량이 18 wt% 보다 낮을 경우, PEO(15 - 에틸렌 - 1-옥텐 혼합물에서 bubble-point 곡선과 cloud-point 곡선이 모두 관측되었다. 에틸렌 함량이 증가함에 따라 PEO(15) - 에틸렌 - l-옥텐 혼합물에서 bubble-point 곡선이 관측되는 온도 범위는 좁아졌으며, PEO(15) - 에틸렌 -1-옥텐 혼합물이 단일상으로 존재하는 온도-압력 영역이 현저히 감소하였다. 에틸렌 함량에 따라 단일상 영역이 감소하는 것은 PEO(15)와 (에틸렌 + 1-옥텐) 혼합용매 사이에 작용하는 분산인력이 줄어들기 때문이다. 에틸렌을 36 wt% 보다 적게 함유한 PEO(15) - 에틸렌 - 1-옥텐 혼합물의 단일상 영역은 온도가 높아짐에 따라 감소하였다. 이와는 대조적으로 에틸렌을 50 wt% 보다 많게 함유한 PEO(15) - 에틸렌 - 1-옥텐 혼합물의 단일상 영역은 온도가 높아짐에 따라 증가하였다. PEO(15) 용해도를 낮추는 혼합용매 사이의 극성인력과 PEO(15) 용해도를 높이는 혼합용매의 밀도는 온도가 낮아짐에 따라 증가한다. 에틸렌 함량이 50 wt% 보다 많을 경우, 혼합용매들의 극성인력 효과가 밀도 효과보다 커서 온도가 낮아짐에 따라 cloud-point 압력은 증가하였다. 에틸렌 함량이 50 wt% 보다 적을 경우, 혼합용매들의 극성인력 효과가 밀도 효과보다 작아서 온도가 낮아짐에 따라 cloud-point 압력은 감소하였다. Cloud-point data to 160℃ and 1,000 bar are presented with poly(ethylene-co-15.3 mole% octene) copolymers (PEO(15)) in pure 1-octene and mixtures of ethylene - 1-octene. The cloud-point curves for PEO(15) - ethylene - 1-octene mixture dramatically increase in pressure to as high as 1,000 bar with an increasing ethylene concentration. At ethylene concentrations less than 18 wt%, the ternary mixture has bubble-and cloud-point curves. As the ethylene concentration of the ternary mixture increases, the bubble-point curve and the single-phase region reduce. The reduction in the single phase region with increasing ethylene concentrations is the result of reduced dispersion interactions between PEO(15) and the mixed solvent. The single-phase region decreases with increasing temperatures when ethylene concentrations are lower than 36 wt%, whereas the single-phase region increases with temperatures at ethylene concentrations greater than 50 wt%. At ethylene concentrations greater than 50 wt% the effect of the polar interactions of the mixed solvent, which is unfavorable to dissolve PEO, is greater than the effect of the density of the mixed solvent. Therefore, the cloud-point pressures increase with a decreasing temperature. However, at ethylene concentrations less than 50 wt%, the cloud-point pressures decrease with temperature, because the effect of the polar interactions is less than the density effect.

Regulation of Ethylene Biosynthesis in Phytochrome Mutants of the Arabidopsis Root

Ji Hye Park(박지혜),Soon Young Kim(김순영) 한국생명과학회 2012 생명과학회지 Vol.22 No.4

식물생장과 발달에 중요한 역할을 하는 phytochrome이 ethylene 생합성에 미치는 영향을 조사하기 위하여 여러 빛 조건에서 키운 phyA, phyB, phyAB에서 ethylene 생합성과 생합성에 관여하는 enzyme activity를 측정하였다. White light에서 키웠을 때 모든 mutant에서 ethylene 생합성이 감소되었다. 특히 double mutant에서는 wild type과 비교하여 37%가 감소하였다. Dark에서 키웠을 때에는 wild type만 감소하였고, mutant에서는 감소효과가 나타나지 않았다. Red light에서 키웠을 때 double mutant에서 급격한 감소가 일어났다. Far-red light 에서 키웠을 때는 phyB만 감소가 일어나지 않았다. Ethylene 생합성에 관여하는 enzyme인 ACO 활성 패턴과는 달리ACS 활성 패턴은 ethylene 생성 패턴과 유사하게 나타났다. 이 결과를 바탕으로 ethylene 생합성에는 phytochromeA와 B 모두 중요한 작용을 하며 특히 Pr 형태의 phytochrome이 ethylene 생성량을 조절한다는 것을 제시한다. 또한 phytochrome은 ethylene 생합성 단계에서 AdoMet가 ACC로 전환되는 단계에서 조절하는 것을 제시한다. In order to investigate the effect of phytochromes on the regulation of ethylene biosynthesis, we measured the ethylene production and the activities of enzymes involved in ethylene biosynthesis using phytochrome mutants such as phyA, phyB, and phyAB of Arabidopsis. The ethylene production was decreased in mutants grown in white light. In particular, double mutants showed a 37% decrease compared to the wild type in ethylene production. When Arabidopsis roots were grown in the dark, mutants did not show a decrease in ethylene production; however, production was significantly decreased in the double mutant grown in red light. Only phyB did not show the decrease in the ethylene production in far-red light. Unlike the ACO activities, the ACS activities of mutants showed the same pattern as the ethylene production under several light conditions. The results of ACS activities confirmed the expression of the ACS gene by RT-PCR analysis. The decrease of ethylene production in mutants was due to the lower activity of ACC synthase, which converts the S-adenosyl-L-methionine (AdoMet) to 1-aminocyclopropane-1-carboxylic acid (ACC), the precursor of ethylene. These results suggested that both phytochrome A and B play an important role in the regulation of ethylene biosynthesis in Arabidopsis roots in the conversion step of AdoMet to ACC, which is regulated by ACS.

Differential Expression of Ethylene Signaling and Biosynthesis Genes in Floral Organs between Ethylene-Sensitive and -Insensitive Rose Cultivars

Suong Tuyet Thi Ha,임진희,인병천 한국원예학회 2019 원예과학기술지 Vol.37 No.2

The plant hormone ethylene regulates diverse aspects of plant growth and development, includingflower senescence and abscission. In cut roses, the impact of ethylene on flower senescence variesgreatly depending on the ethylene sensitivity of the floral organs, which is determined by the varietyof the rose. To understand the relationship between ethylene synthesis and sensitivity in floral organs,we examined tissue-specific differences in gene expression and regulation using two rose cultivarswith differing ethylene sensitivity. We monitored the expression patterns of genes related to ethylenebiosynthesis (RhACS1, RhACS2, RhACS3, RhACS4, and RhACO1), receptor (RhETR1, RhETR2,RhETR3, RhETR4, and RhETR5), and signaling (RhCTR1, RhCTR2, RhEIN3-1, RhEIN3-2, andRhEIN3-3) in various floral organs of ethylene-sensitive (SENS; ‘All For Love’) and -insensitive(INSENS; ‘Peach Valley’) rose cultivars. The expression of ethylene-related genes in all floral organswas generally higher in SENS than INSENS cultivars. The presence of exogenous ethylene acceleratedthe accumulation of RhACS1-4 and RhACO1 transcripts in SENS petals and leaves and in INSENSstamens and stigmas, leading to an increase in RhETR1-5 expression in the floral organs. Meanwhile,RhCTR1-2 expression decreased considerably, with a consequent increase in RhEIN3 transcripts inSENS petals and leaves and INSENS stamens and stigmas. The differential expression of ethylenerelatedgenes in the same tissues indicates that the site of initiation of the ethylene-inducible responsesvaries among the varieties, and this is probably related to the ethylene sensitivity of the flowers.