THE INTERACTION BETWEEN JASMONATES AND ABSCISIC ACID DURING RIPENING OF APPLE FRUIT

Fruit abscission is a complex physiological process that is regulated by internal and environmental factors. During early development, apple fruit are exposed to extreme temperature fluctuations that are associated with premature fruit drop; however, their effect on fruit abscission is largely unknown. We hypothesized that fruit abscission is triggered by cold stress and investigated the molecular basis of premature fruit drop using RNA-Seq and metabolomics data from apple fruit undergoing abscission following cold stress in the field. Genes responsive to abscisic acid signaling and cell wall degradation were upregulated during abscission, consistent with the increased abscisic acid concentrations detected by liquid chromatography-mass spectrometry. We performed ex vivo cold shock experiments with excised tree subunits consisting of a branch, pedicel, and fruit. Abscission induction occurred in the cold-stressed subunits with concurrent upregulation of abscisic acid biosynthesis (MdNCED1) and metabolism (MdCYP707A) genes, and ethylene biosynthesis (MdACS1) and receptor (MdETR2) genes in the pedicel. Another key finding was the activation of cytoplasmic streaming in abscission-zone cells detected by electron microscopy. Our results provide a novel insight into the molecular basis of fruit abscission physiology in response to cold stress in apple.

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Effects of S-Abscisic Acid and (+)-8′-Acetylene Abscisic Acid on Fruit Set and Stomatal Conductance in Apple

HortScience ◽

10.21273/hortsci.49.6.763 ◽

2014 ◽

Vol 49 (6) ◽

pp. 763-768 ◽

Cited By ~ 14

Author(s):

Steven J. McArtney ◽

Suzanne R. Abrams ◽

Derek D. Woolard ◽

Peter D. Petracek

Keyword(s):

Abscisic Acid ◽

Stomatal Conductance ◽

Fruit Set ◽

Apple Fruit ◽

Leaf Abscission ◽

Stomatal Limitation ◽

Cloudy Weather ◽

Photosynthetic Inhibitors ◽

Treatment Application ◽

Fruit Diameter

Fruit set of apple can be reduced by cloudy weather, short-term shade treatments, or application of photosynthetic inhibitors when the young fruit are ≈8 to 15 mm in diameter, indicating that fruit are sensitive to a transient carbohydrate stress during this period. We investigated the potential for S-abscisic acid (ABA) and an ABA analog [(+)-8′-acetylene ABA] to chemically thin apple fruit by causing a stomatal limitation of photosynthesis. Stomatal conductance (gS) of ‘Imperial Gala’/M.7 was reduced by 60% 3 h after application of 250 mg·L−1 ABA or 25 mg·L−1 (+)-8′-acetylene ABA. Stomatal conductance began to recover 4 days after application but did not return to control levels until 19 days after treatment. Application of 250 mg·L−1 ABA combined with 100 mg·L−1 6-benzyladenine (6-BA) when mean fruit diameter was ≈10 mm reduced fruit set of ‘Gala’/M.7 but not ‘Pink Lady™’/M.7 or ‘Morganspur Delicious’/MM.111. Fruit set of ‘Pink Lady™’/M.7 was reduced by application of 20 mg·L−1 (+)-8′-acetylene ABA + 100 mg·L−1 6-BA at full bloom or 10 mg·L−1 (+)-8′-acetylene ABA + 100 mg·L−1 6-BA at the 10-mm fruit diameter stage. Fruit set of ‘Morganspur Delicious’/MM.111 was reduced by application of 25 mg·L−1 (+)-8′-acetylene ABA, either alone or in combination with 75 mg·L−1 6-BA, at the 10-mm fruit diameter stage. ABA and (+)-8′-acetylene ABA triggered leaf abscission at rates above 250 mg·L−1 and 25 mg·L−1, respectively. Fruit set and gS data from the present studies indicate the biological activity of (+)-8′-acetylene ABA is 10-fold higher than ABA. These results suggest that ABA and (+)-8′-acetylene ABA reduced fruit set by causing a stomatal limitation in photosynthesis that resulted in a transient carbohydrate stress. Thinning responses to ABA and (+)-8′-acetylene ABA at the concentrations used in these experiments were reduced compared with standard concentrations of currently available chemical thinning agents. However, increasing the concentration of ABA or (+)-8′-acetylene ABA to levels that would achieve comparable thinning are also likely to result in unacceptable leaf abscission.

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Four glycoside hydrolases are differentially modulated by auxins, cytokinins, abscisic acid and gibberellic acid in apple fruit callus cultures

Plant Cell Tissue and Organ Culture (PCTOC) ◽

10.1007/s11240-008-9438-1 ◽

2008 ◽

Vol 95 (3) ◽

pp. 257-263 ◽

Cited By ~ 8

Author(s):

Paula Alayón-Luaces ◽

Eduardo A. Pagano ◽

Luis A. Mroginski ◽

Gabriel O. Sozzi

Keyword(s):

Abscisic Acid ◽

Gibberellic Acid ◽

Callus Cultures ◽

Apple Fruit ◽

Glycoside Hydrolases

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Induction of Senescence and Foliar Abscission in Apple Trees with the Use of Abscisic Acid

Journal of Experimental Agriculture International ◽

10.9734/jeai/2019/v35i530217 ◽

2019 ◽

pp. 1-10

Author(s):

Caroline De Fátima Esperança ◽

José Luiz Petri ◽

Andrea De Rossi ◽

Marcelo Couto ◽

André Amarildo Sezerino ◽

...

Keyword(s):

Abscisic Acid ◽

Block Design ◽

Apple Fruit ◽

Fruit Tree ◽

First Year ◽

Leaf Fall ◽

Growing Seasons ◽

Apple Leaves ◽

Randomized Block Design ◽

Second Year

Aims: Evaluate the effects of different concentrations of abscisic acid (ABA) on adult plants of productive age of ‘Daiane’ and ‘Fuji Suprema’, to follow the ecophysiological effects and their efficiency in inducing leaf senescence, sprouting and productivity, in the Midwestern region of the state of Santa Catarina. Study Design: The experiment was arranged in a randomized block design with six replications. Place and Duration of Study: The experiment was carried out in the municipality of Caçador, Brazil (latitude 26º50’07” S, longitude 50º58’32” W, altitude 969 meters), during the growing seasons of 2013/2014 and 2014/2015. Methodology: The apple fruit tree were submitted to the following treatments: 1) Control (without treatment), 2) abscisic acid 750 mg L-1, 3) abscisic acid 750 + 750 mg L-1, 4) abscisic acid 1500 mg L-1 and 5) abscisic acid 1500 + 1500 mg L-1. ABA applications in the first year were carried out on May 2, 2013 in treatments 2, 3, 4, and 5, and after 11 days (05/13/13) the plants of treatments 3 and 5 were sprayed again. In the second year, ABA applications were carried out on May 6 and 15, 2014, following the same application methodology described for the first year. As the source of abscisic acid (ABA) the commercial product ProTone® (20% i.a.) was used, without the use of adjuvant. The exogenous application of ABA was effective in promoting the senescence and leaf fall of the ‘Daiane’ and ‘Fuji Suprema’ cultivars. In the 2013/2014 season, the concentration of 750 mg L-1 was enough to induce 100% leaf fall in 'Daiane' plants. However, a difference was observed between the concentrations of ABA used. There was a difference between concentrations and number of applications. Lower concentrations were efficient and deflated as much as the higher concentration. The application of ABA induces the abscission of apple leaves in early autumn in 'Daiane' and 'Fuji Suprema' apple plants. The ABA does not affect shoots of axillary buds and anticipates the beginning of shoots.

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