Advances in abscission signaling

Patharkar, O. Rahul; Walker, John C.

doi:10.1093/jxb/erx256

Cited by 97 publications

(74 citation statements)

References 56 publications

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“…Organ shedding is a common phenomenon in plants, which is of great significance to the growth and development during the lifespan of a plant, especially the yield of crops [1]. Abscission ensures that plants can shed organs when they are no longer needed, such as flowers, fruits, and senescent leaves [2] and also as a means of escaping infected or damaged organs [3].…”

Section: Introductionmentioning

confidence: 99%

Chemical Defoliant Promotes Leaf Abscission by Altering ROS Metabolism and Photosynthetic Efficiency in Gossypium hirsutum

Jin

Wang

et al. 2020

IJMS

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Chemical defoliation is an important part of cotton mechanical harvesting, which can effectively reduce the impurity content. Thidiazuron (TDZ) is the most used chemical defoliant on cotton. To better clarify the mechanism of TDZ promoting cotton leaf abscission, a greenhouse experiment was conducted on two cotton cultivars (CRI 12 and CRI 49) by using 100 mg L −1 TDZ at the eight-true-leaf stage. Results showed that TDZ significantly promoted the formation of leaf abscission zone and leaf abscission. Although the antioxidant enzyme activities were improved, the reactive oxygen species and malondialdehyde (MDA) contents of TDZ increased significantly compared with CK (water). The photosynthesis system was destroyed as net photosynthesis (Pn), transpiration rate (Tr), and stomatal conductance (Gs) decreased dramatically by TDZ. Furthermore, comparative RNA-seq analysis of the leaves showed that all of the photosynthetic related genes were downregulated and the oxidation-reduction process participated in leaf shedding caused by TDZ. Consequently, a hypothesis involving possible cross-talk between ROS metabolism and photosynthesis jointly regulating cotton leaf abscission is proposed. Our findings not only provide important insights into leaf shedding-associated changes induced by TDZ in cotton, but also highlight the possibility that the ROS and photosynthesis may play a critical role in the organ shedding process in other crops.Previous studies have found that ethylene accelerates organ abscission, while auxin inhibits this process [5][6][7][8][9]. Meanwhile, researchers have paid attention to the fact that multiple cell wall-degrading enzymes are activated to dissolve the cell wall and middle lamella of abscission zone, including cellulases, pecticlyases, polygalactosidases [10][11][12]. Some research has found that hydrogen peroxide (H 2 O 2 ) acts downstream from ethylene and plays a role in the cell-wall degradation process in abscission signaling [13,14].Reactive oxygen species (ROS), including H 2 O 2 , superoxide, singlet oxygen, and the hydroxyl radical, are produced in response to environmental stress [13]. Environmental stresses (such as drought, cold stress, salt stress, and pathogen attack) are often accompanied by leaf abscission [15][16][17], but the relationship between stress and abscission is rarely studied. Excessive ROS can damage cellular components, including lipids, protein, and nucleic acids [18]. ROS produced at the abscission zone site play an important role in regulating leaf abscission under drought stress in cassava (Manihot esculenta Crantz) [19]. Recent studies have found that ROS do not work in the fruit abscission zone of olives (Olea europaea L.), but only alter oxidative stress in the abscission zone of leaves and then mediate abscission induced by ethephon [20]. Previous studies have shown that insufficient carbohydrate accumulation and distribution can lead to flower and fruit abscission. For example, carbohydrate stress can induce longan (Dimocarpus longan Lour.) fruit abscissi...

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Section: Introductionmentioning

confidence: 99%

Chemical Defoliant Promotes Leaf Abscission by Altering ROS Metabolism and Photosynthetic Efficiency in Gossypium hirsutum

Jin

Wang

et al. 2020

IJMS

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“…Abscission is commonly associated with the sequence of a regulated process resulting in natural shedding (separation) of plant organs such as leaves, branches, flowers and fruits, from the parent plant [1][2][3][4][5][6]. During abscission, mechanical weakening of cell walls at the abscission zone is brought about by the degradation of the middle lamella by multiple cell-wall degrading enzymes such as cellulase, polygalacturonases, pectin methyl esterases, etc.…”

Section: Introductionmentioning

confidence: 99%

Formation of the Secondary Abscission Zone Induced by the Interaction of Methyl Jasmonate and Auxin in Bryophyllum calycinum: Relevance to Auxin Status and Histology

Marasek-Ciołakowska

Dziurka

Kowalska

et al. 2020

IJMS

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The interaction of methyl jasmonate (JA-Me) and indole-3-acetic acid (IAA) to induce the formation of the secondary abscission zone in the middle of internode segments of Bryophyllum calycinum was investigated in relation to auxin status and histology. When IAA at 0.1% (w/w, in lanolin) was applied to the segments, the formation of the secondary abscission zone at a few mm above the treatment in the apical direction was observed. On the contrary, IAA at 0.5% (w/w, in lanolin) did not induce the formation of the secondary abscission zone. JA-Me at 0.5% (w/w, in lanolin) applied to the middle of internode segments kept in the normal (natural) or inverted positions also induced the formation of the secondary abscission zone below and above parts of the treatment. IAA at 0.5% applied to the cut surface of the upper part of the segments completely prevented the formation of the secondary abscission zone induced by JA-Me. Simultaneous application of IAA 0.5% with JA-Me 0.5% in the middle part of the internode segments induced the formation of the secondary abscission zone at 10 mm to 12 mm above the treatment. Histological analyses indicated that the formation of the secondary abscission zone was characterized by the presence of newly synthesized cell plates that resulted from periclinal cell division within one layer of mother cells in stems. The effects of IAA (0.1%) and JA-Me (0.5%) on the formation of the secondary abscission zone were histologically similar. Comprehensive analyses of plant hormones revealed that the balance of the endogenous levels of IAA in both sides adjacent to the abscission zone was significantly disturbed when the secondary abscission formation was induced by the application of IAA. These results strongly suggest that an auxin gradient is important in the formation of the secondary abscission zone in the internode segments of B. calycinum, and IAA gradient results from polar IAA transport from the application site. IAA is important in the regulation of formation of the secondary abscission zone induced by JA-Me. Further possible mechanisms of the formation of the secondary abscission zone in the internode segments of B. calycinum are also discussed in the interaction of JA-Me and IAA.

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“…Six major research themes which address this and constitute the basis of this special issue include (1) changes in the photosynthetic apparatus during leaf senescence, (2) the interaction of endogenous and exogenous signals with senescence pathways, (3) integrative, multi-layered, spatio-temporal networks in leaf senescence, (4) the evolutionary basis of leaf senescence, (5) extended applications of multi-omics technologies to explore genetic elements and their networks that control plant senescence, and integration of multiple types of omics and genetic/physiological data, and (6) source–sink interactions for enhancing crop yield. Although the majority of the reviews focus on leaf senescence, Ma et al (2018) discuss recent progress in understanding hormone-regulated petal senescence; and Patharkar and Walker (2018) address recent advances in understanding the abscission signalling network, as well as future directions for the application of basic abscission research to agriculture.…”

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confidence: 99%