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Probable mechanism of endogenous GA3 regulates tuber growth in yam. The accumulation of active GA3 is controlled by the activities of DoGA20ox1, DoGA3ox1, DoGA2ox3, and DoGA2ox4, and the degradation of DoDELLA1 proteins due to the formation of GA-DoGID1-DoDELLA. Active GA3 improves GA response genes expression, such as DoEXP1, DoEXP2, DoEXP3, DoEXP4, DoEXP5, DoXTH1, DoXTH2, and DoXTH3, and enhance tuber growth
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Key message
Endogenous and exogenous GA3 responses to DoEXP and DoXTH depend on the DoGA20ox1, DoGA3ox1, DoGA2ox3, DoGA2ox4, DoGID1a, and DoDELLA1 to regulate yam tuber growth.
Abstract
Yam tuber undergoes significant alteration in morphogenesis and functions during growth, and gibberellins (GA) are considered potentially important regulators of t...
Citations
... Similarly, in transgenic Arabidopsis plants, the expression of AtGA3OX1 was significantly increased when treated with a lower concentration of GA3 (Zhu et al., 2022), which is consistent with our findings. Furthermore, the expression of DELLAs was depressed after GA3 treatment , Zhou et al., 2021, Zhu et al., 2022. Therefore, more in-depth research is needed to understand the tissue-specific expression pattern at various GA3 treatment levels and to investigate the intricate regulatory mechanisms of the genes involved in GA biosynthesis and DELLA in transgenic plants. ...
D‐2‐hydroxyglutarate dehydrogenase (D2HGDH) is a mitochondrial enzyme containing flavin adenine dinucleotide FAD, existing as a dimer, and it facilitates the specific oxidation of D‐2HG to 2‐oxoglutarate (2‐OG), which is a key intermediate in the tricarboxylic acid (TCA) cycle. A Genome‐wide expression analysis (GWEA) has indicated an association between GhD2HGDH and flowering time. To further explore the role of GhD2HGDH , we performed a comprehensive investigation encompassing phenotyping, physiology, metabolomics, and transcriptomics in Arabidopsis thaliana plants overexpressing GhD2HGDH . Transcriptomic and qRT‐PCR data exhibited heightened expression of GhD2HGDH in upland cotton flowers. Additionally, early‐maturing cotton exhibited higher expression of GhD2HGDH across all tissues than delayed‐maturing cotton. Subcellular localization confirmed its presence in the mitochondria. Overexpression of GhD2HGDH in Arabidopsis resulted in early flowering. Using virus‐induced gene silencing (VIGS), we investigated the impact of GhD2HGDH on flowering in both early‐ and delayed‐maturing cotton plants. Manipulation of GhD2HGDH expression levels led to changes in photosynthetic pigment and gas exchange attributes. GhD2HGDH responded to gibberellin (GA3) hormone treatment, influencing the expression of GA biosynthesis genes and repressing DELLA genes. Protein interaction studies, including yeast two‐hybrid, luciferase complementation (LUC), and GST pull‐down assays, confirmed the interaction between GhD2HGDH and GhSOX ( Sulfite oxidase ). The metabolomics analysis demonstrated GhD2HGDH's modulation of the TCA cycle through alterations in various metabolite levels. Transcriptome data revealed that GhD2HGDH overexpression triggers early flowering by modulating the GA3 and photoperiodic pathways of the flowering core factor genes. Taken together, GhD2HGDH positively regulates the network of genes associated with early flowering pathways.
... They showed that GA 3 can stimulate the expansion and production of new tubers, increasing tuber weight and yield (Kim et al., 2005;Yoshida et al., 2008;Gong et al., 2016). Zhou et al. (2021) showed that GA 3 is mainly involved in tuber growth at the early expansion stage since it acts on cell expansion and division during tissue development. On cassava, Oluwasanya (2020) noted an improvement in tuber yields with flower-enhancing treatments (STS and BA) compared to untreated controls. ...
Developing novel white Guinea yam (Dioscorea rotundata) varieties is constrained by the sparse, erratic, and irregular flowering behavior of most genotypes. We tested the effectiveness of nine agronomic and hormonal treatments to enhance flowering on D. rotundata under field conditions. Genotypes responded differently to flower-inducing treatments (p<0.001). Of the test treatments, pruning and silver thiosulfate (STS) were effective in increasing the number of spikes per plant and the flowering intensity on both sparse flowering and monoecious cultivars. STS and tuber removal treatments promoted female flowers on the monoecious variety while pruning and most treatments involving pruning favored male flowers. None of the treatments induced flowering on Danacha, a non-flowering yam landrace. Flower-enhancing treatments had no significant effect on flower fertility translated by the fruit set, since most treatments recorded fruit sets above the species’ average crossability rate. Flower-enhancing techniques significantly influenced number of tubers per plant (p = 0.024) and tuber dry matter content (DMC, p = 0.0018) but did not significantly affect plant tuber yield. Nevertheless, treatments that could enhance substantially flowering intensity, such as pruning and STS, reduced tuber yield. DMC had negative associations with all flowering-related traits. This study provided insights into white yam flower induction and suggests promising treatments that can be optimized and used routinely to increase flowering in yam crop, without significantly affecting flower fertility and tuber yield.
... Researchers have successfully developed microtuber culture techniques, providing virus-free tubers suitable for transportation and storage [7]. Tuberization in yam [8] and other tuberous crops [9,10] may involve hormomes (e.g., gibberellins (GAs) and abscisic acid (ABA)) and genes in GA and ABA synthesis, catabolism, and signalling [11][12][13]. Tuberization in model plant species, potato (Solanum tuberosum) [14] may also be regulated by photoperiodic genes such as circadian-regulated gene CONSTANS (CO) and the CO/ FT module [15,16]. In potato, StCO inhibited the transcription of the tuberigen StSP6A in leaves and repressed tuberization in a photoperiod-dependent manner. ...
BBX proteins play important roles in all of the major light-regulated developmental processes. However, no systematic analysis of BBX gene family regarding the regulation of photoperiodic microtuber formation has been previously performed in yam. In this study, a systematic analysis on the BBX gene family was conducted in three yam species, with the results, indicating that this gene plays a role in regulating photoperiodic microtuber formation. These analyses included identification the BBX gene family in three yam species, their evolutionary relationships, conserved domains, motifs, gene structure, cis-acting elements, and expressional patterns. Based on these analyses, DoBBX2/DoCOL5 and DoBBX8/DoCOL8 showing the most opposite pattern of expression during microtuber formation were selected as candidate genes for further investigation. Gene expression analysis showed DoBBX2/DoCOL5 and DoBBX8/DoCOL8 were highest expressed in leaves and exhibited photoperiod responsive expression patterns. Besides, the overexpression of DoBBX2/DoCOL5 and DoBBX8/DoCOL8 in potato accelerated tuber formation under short-day (SD) conditions, whereas only the overexpression of DoBBX8/DoCOL8 enhanced the accelerating effect of dark conditions on tuber induction. Tuber number was increased in DoBBX8/DoCOL8 overexpressing plants under dark, as well as in DoBBX2/DoCOL5 overexpressing plants under SD. Overall, the data generated in this study may form the basis of future functional characterizations of BBX genes in yam, especially regarding their regulation of microtuber formation via the photoperiodic response pathway.
... Several previous studies have focused on the genetic basis of tuber initiation and expansion in D. polystachya (55,73,105) but the control of tuber shape is poorly understood, despite its major impact on the efficiency of mechanical harvesting (6,106). By comparing the transcriptomes of two closely related tuber shape variants (F60 and F2000) each divided into three tuber sections, we identified several candidate genes involved in tuber development. ...
... Furthermore, we did not observe a consistent expression pattern among the different F2000 tuber parts because genes annotated as GA20ox and GA2ox were upregulated in the F2000M vs. F2000T comparison. This agrees with a previous report suggesting the outcome was the result of feedback mechanisms or other hormones influencing tuber growth (55,105). The varied response of GA2ox family enzymes to GA 3 treatment may reflect their different physiological roles, or may reflect different organ and tissue types (105). ...
... This agrees with a previous report suggesting the outcome was the result of feedback mechanisms or other hormones influencing tuber growth (55,105). The varied response of GA2ox family enzymes to GA 3 treatment may reflect their different physiological roles, or may reflect different organ and tissue types (105). In our study, we detected a slight decrease in DpGA3ox1 expression and an increase in DpGA2ox expression following epi-BL treatment, but these changes were not significant compared to the control group. ...
Dioscorea is an important but underutilized genus of flowering plants that grows predominantly in tropical and subtropical regions. Several species, known as yam, develop large underground tubers and aerial bulbils that are used as food. The Chinese yam (D. polystachya Turcz.) is one of the few Dioscorea species that grows well in temperate regions and has been proposed as a climate-resilient crop to enhance food security in Europe. However, the fragile, club-like tubers are unsuitable for mechanical harvesting, which is facilitated by shorter and thicker storage organs. Brassinosteroids (BRs) play a key role in plant cell division, cell elongation and proliferation, as well as in the gravitropic response. We collected RNA-Seq data from the head, middle and tip of two tuber shape variants: F60 (long, thin) and F2000 (short, thick). Comparative transcriptome analysis of F60 vs. F2000 revealed 30,229 differentially expressed genes (DEGs), 1,393 of which were differentially expressed in the growing tip. Several DEGs are involved in steroid/BR biosynthesis or signaling, or may be regulated by BRs. The quantification of endogenous BRs revealed higher levels of castasterone (CS), 28-norCS, 28-homoCS and brassinolide in F2000 compared to F60 tubers. The highest BR levels were detected in the growing tip, and CS was the most abundant (439.6 ± 196.41 pmol/g in F2000 and 365.6 ± 112.78 pmol/g in F60). Exogenous 24-epi-brassinolide (epi-BL) treatment (20 nM) in an aeroponic system significantly increased the width-to-length ratio (0.045 ± 0.002) compared to the mock-treated plants (0.03 ± 0.002) after 7 weeks, indicating that exogenous epi-BL produces shorter and thicker tubers. In this study we demonstrate the role of BRs in D. polystachya tuber shape, providing insight into the role of plant hormones in yam storage organ development. We found that BRs can influence tuber shape in Chinese yam by regulating the expression of genes involved cell expansion. Our data can help to improve the efficiency of Chinese yam cultivation, which could provide an alternative food source and thus contribute to future food security in Europe.
... Similarly, in Gladiolus hybridus, GA prevents starch synthesis and corm development via GhSUS2 activation [78]. On the other hand, in Panax ginseng and yam, GA promotes secondary growth of storage roots [79,80]. It has been suggested that a high ABA/GA ratio promotes tuber development, while GA preponderance delays tuber formation [81]. ...
Gibberellins have been classically related to a few key developmental processes, thus being essential for the accurate unfolding of plant genetic programs. After more than a century of research, over one hundred different gibberellins have been described. There is a continuously increasing interest in gibberellins research because of their relevant role in the so-called "Green Revolution", as well as their current and possible applications in crop improvement. The functions attributed to gibberellins have been traditionally restricted to the regulation of plant stature, seed germination, and flowering. Nonetheless, research in the last years has shown that these functions extend to many other relevant processes. In this review, the current knowledge on gibberellins homeostasis and mode of action is briefly outlined, while specific attention is focused on the many different responses in which gibberellins take part. Thus, those genes and proteins identified as being involved in the regulation of gibberellin responses in model and non-model species are highlighted. The present review aims to provide a comprehensive picture of the state-of-the-art perception of gibberellins molecular biology and its effects on plant development. This picture might be helpful to enhance our current understanding of gibberellins biology and provide the know-how for the development of more accurate research and breeding programs.
... However, the major bioactive GAs are restricted to GA 1 , GA 3 , GA 4 , and GA 7 , while others are considered as the precursors or the deactivated forms of bioactive GAs [21]. GA has been implicated in multiple developmental processes via dominant reinforcement of cell elongation or sometimes cell division, as exemplified by tuber growth [1,17,18,[20][21][22][23]. Potato tuber formation is retarded because of the stolon elongation promoted by the exogeneous bioactive GA 4/7 [18], while the yam tuber and bulbil yield are increased by the application of GA [23,24]. ...
... However, the major bioactive GAs are restricted to GA 1 , GA 3 , GA 4 , and GA 7 , while others are considered as the precursors or the deactivated forms of bioactive GAs [21]. GA has been implicated in multiple developmental processes via dominant reinforcement of cell elongation or sometimes cell division, as exemplified by tuber growth [1,17,18,[20][21][22][23]. Potato tuber formation is retarded because of the stolon elongation promoted by the exogeneous bioactive GA 4/7 [18], while the yam tuber and bulbil yield are increased by the application of GA [23,24]. The opposite effects of GA treatments suggest the intricate roles of GA during tuber development in different stem/tuber root crops [23]. ...
... GA has been implicated in multiple developmental processes via dominant reinforcement of cell elongation or sometimes cell division, as exemplified by tuber growth [1,17,18,[20][21][22][23]. Potato tuber formation is retarded because of the stolon elongation promoted by the exogeneous bioactive GA 4/7 [18], while the yam tuber and bulbil yield are increased by the application of GA [23,24]. The opposite effects of GA treatments suggest the intricate roles of GA during tuber development in different stem/tuber root crops [23]. ...
Root and tuber crops are of great importance. They not only contribute to feeding the population but also provide raw material for medicine and small-scale industries. The yield of the root and tuber crops is subject to the development of stem/root tubers, which involves the initiation, expansion, and maturation of storage organs. The formation of the storage organ is a highly intricate process, regulated by multiple phytohormones. Gibberellins (GAs) and abscisic acid (ABA), as antagonists, are essential regulators during stem/root tuber development. This review summarizes the current knowledge of the roles of GA and ABA during stem/root tuber development in various tuber crops.
... accessed on 2 October 2021). The target gene information and primers are listed in Table 1 [39,52]. ...
... Moreover, FaSOC1 regulates the differentiation of axillary buds to runners or axillary leaf rosettes, probably through the activation of gibberellin-biosynthesis-related genes [39,52,70]. In addition, the function of FaTFL1 as a major floral repressor and its photoperiodic control in the shoot apex explains seasonal flowering in strawberries. ...
The significant effects of lighting on plants have been extensively investigated, but research has rarely studied the impact of different lighting directions for the strawberry plant. To understand the optimal lighting direction for better growth and development, this study investigated how strawberries respond to variations in the lighting direction to help fine-tune the growth environment for their development. We examined how the lighting direction affects plant morphophysiology by investigating plant growth parameters, leaf anatomy, epidermal cell elongation, stomatal properties, physiological characteristics, and expressions of runner induction-related genes (FaSOC1 and FaTFL1) and gibberellin (GA) biosyntheses-related genes (FaGA20ox2 and FaGA20ox4). In closed-type plant factory units, the rooted cuttings of strawberry (Fragaria × ananassa Duch.) ‘Suhlyang’ were subjected to a 10-h photoperiod with a 350 μmol∙m−2∙s−1 photosynthetic photon flux density (PPFD) provided by light-emitting diodes (LEDs) from three directions relative to the plants: top, side, and bottom. Our results demonstrated that the side lighting profoundly promoted not only morphophysiology, but also runner formation, by upregulating photosynthesis in strawberries. Side lighting can bring commercial benefits, which include reduced economic costs, easier controllability, and harmlessness to plants. This will help provide new insights for the propagation of the most commonly cultivated strawberries in South Korea.
... accessed on 2 October 2021). The target gene information and primers are listed in Table 1 [39,52]. ...
... Moreover, FaSOC1 regulates the differentiation of axillary buds to runners or axillary leaf rosettes, probably through the activation of gibberellin-biosynthesis-related genes [39,52,70]. In addition, the function of FaTFL1 as a major floral repressor and its photoperiodic control in the shoot apex explains seasonal flowering in strawberries. ...
Cyperus rotundus L. is a globally distributed noxious weed that poses a significant challenge for control due to its fast and efficient propagation through the tuber, which is the primary reproductive organ. Gibberellic acid (GA 3 ) has proved to be crucial for tuberization in tuberous plants. Therefore, understanding the relationship between GA 3 and tuber development and propagation of C.roundus will provide valuable information for controlling this weed. This study shows that the content of GA 3 decreases with tuber development, which corresponds to lower expression of bioactive GA 3 synthesis genes ( CrGA20ox , two CrGA3oxs) and two up-regulated GA 3 catabolism genes ( CrGA2oxs ), indicating that GA 3 is involved in tuber development. Simultaneously, the expressions of CrDELLAs and CrGID1 decline with tuber growth and GA 3 decreasing, and Yeast two-hybrid (Y2H) assays confirm that the GA 3 signaling is DELLA-dependent. Furthermore, exogenous application of GA 3 markedly reduces the number and the width of tuber, and represses the growth of tuber chain, further confirming the negative impact that GA 3 has on tuber development and propagation. Taken together, these results demonstrate that GA 3 is involved in tuber development and regulated by the DELLA-dependent pathway in C. rotundus , and plays a negative role in tuber development and propagation.
