Regulation of ABA and GA Levels During Seed Development and Germination inArabidopsis

Yamaguchi, Shinjiro; Kamiya, Yûji; Nambara, Eiji

doi:10.1002/9780470988848.ch9

Cited by 39 publications

(10 citation statements)

References 94 publications

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“…However, plants have evolved efficient antioxidative defense mechanisms, including the activities of antioxidant enzymes and the regulation of non-enzymatic antioxidants to reduce ROS induced oxidative damages (Posmyk et al, 2009). Plant hormones are important signaling molecules that respond to environmental changes in seed germination (Yamaguchi, Kamiya & Nambara, 2007). Gibberellins (GA) and abscisic acid (ABA) are well-known phytohormones that play crucial roles in seed germination and early seedling establishment (Shu et al, 2018;Ahammed et al, 2020a).…”

Section: Introductionmentioning

confidence: 99%

Melatonin improves the germination rate of cotton seeds under drought stress by opening pores in the seed coat

Bai

Xiao

Zhang

et al. 2020

PeerJ

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The germination of cotton (Gossypium hirsutum L.) seeds is affected by drought stress; however, little is known about the physiological mechanism affecting germination and the effect of melatonin (MT) on cotton seed germination under drought stress. Therefore, we studied the effects of exogenous MT on the antioxidant capacity and epidermal microstructure of cotton under drought stress. The results demonstrated a retarded water absorption capacity of testa under drought stress, significantly inhibiting germination and growth in cotton seeds. Drought stress led to the accumulation of reactive oxygen species (ROS), malondialdehyde (MDA), and osmoregulatory substances (e.g., proline, soluble protein, and soluble sugars); it also decreased the activity of antioxidant enzymes and α-amylase. Drought stress inhibited gibberellin acid (GA3) synthesis and increased abscisic acid (ABA) content, seriously affecting seed germination. However, seeds pre-soaked with MT (100 µM) showed a positive regulation in the number and opening of stomata in cotton testa. The exogenous application of MT increased the germination rate, germination potential, radical length, and fresh weight, as well as the activities of superoxide dismutase (SOD), peroxidase (POD), and α-amylase. In addition, MT application increased the contents of organic osmotic substances by decreasing the hydrogen peroxide (H2O2), superoxide anion (O2-), and MDA levels under drought stress. Further analysis demonstrated that seeds pre-soaked with MT alleviated drought stress by affecting the ABA and GA3 contents. Our findings show that MT plays a positive role in protecting cotton seeds from drought stress.

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Section: Introductionmentioning

confidence: 99%

Melatonin improves the germination rate of cotton seeds under drought stress by opening pores in the seed coat

Bai

Xiao

Zhang

et al. 2020

PeerJ

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“…Abscisic acid (ABA) also participates in the regulation of seed germination in an opposite direction to the action of GAs (Kucera et al, 2005;Yamaguchi et al, 2006). Recent studies of tissue-specific expression of ABA metabolism and response genes in Arabidopsis seed germination suggest that this hormone plays a role in altering cellular functions both in embryo and endosperm.…”

Section: Introductionmentioning

confidence: 99%

Transcription factor AtTCP14 regulates embryonic growth potential during seed germination in Arabidopsis thaliana

et al. 2007

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SummaryTo understand the molecular mechanisms underlying regulation of seed germination, we searched enriched cis elements in the upstream regions of Arabidopsis genes whose transcript levels increased during seed germination. Using available published microarray data, we found that two cis elements, Up1 or Up2, which regulate outgrowth of Arabidopsis axillary shoots, were significantly over-represented. Classification of Up1-and Up2-containing genes by gene ontology revealed that protein synthesis-related genes, especially ribosomal protein genes, were highly over-represented. Expression analysis using a reporter gene driven by a synthetic promoter regulated by these elements showed that the Up1 is necessary and sufficient for germination-associated gene induction, whereas Up2 acts as an enhancer of Up1. Up1-mediated gene expression was suppressed by treatments that blocked germination. Up1 is almost identical to the site II motif, which is the predicted target of TCP transcription factors. Of 24 AtTCP genes, AtTCP14, which showed the highest transcript level just prior to germination, was functionally characterized to test its involvement in the regulation of seed germination. Transposon-tagged lines for AtTCP14 showed delayed germination. In addition, germination of attcp14 mutants exhibited hypersensitivity to exogenously applied abscisic acid and paclobutrazol, an inhibitor of gibberellin biosynthesis. AtTCP14 was predominantly expressed in the vascular tissues of the embryo, and affected gene expression in radicles in a non-cell-autonomous manner. Taken together, these results indicate that AtTCP14 regulates the activation of embryonic growth potential in Arabidopsis seeds.

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“…ABA is involved in the induction and maintenance of seed dormancy, whereas GA releases dormancy and induces germination. ABA and GA levels are determined by the relative rates of biosynthesis and deactivation of their chemical precursors and conjugates, the levels of which are mainly controlled by gene expression (4,5). In contrast, hormone signal transduction is considered to be posttranslationally regulated.…”

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confidence: 99%

Induction of 9- cis -epoxycarotenoid dioxygenase in Arabidopsis thaliana seeds enhances seed dormancy

Martínez‐Andújar

Ordiz

Huang

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

121

101

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Full understanding of mechanisms that control seed dormancy and germination remains elusive. Whereas it has been proposed that translational control plays a predominant role in germination, other studies suggest the importance of specific gene expression patterns in imbibed seeds. Transgenic plants were developed to permit conditional expression of a gene encoding 9-cis-epoxycarotenoid dioxygenase 6 (NCED6), a rate-limiting enzyme in abscisic acid (ABA) biosynthesis, using the ecdysone receptor-based plant gene switch system and the ligand methoxyfenozide. Induction of NCED6 during imbibition increased ABA levels more than 20-fold and was sufficient to prevent seed germination. Germination suppression was prevented by fluridone, an inhibitor of ABA biosynthesis. In another study, induction of the NCED6 gene in transgenic seeds of nondormant mutants tt3 and tt4 reestablished seed dormancy. Furthermore, inducing expression of NCED6 during seed development suppressed vivipary, precocious germination of developing seeds. These results indicate that expression of a hormone metabolism gene in seeds can be a sole determinant of dormancy. This study opens the possibility of developing a robust technology to suppress or promote seed germination through engineering pathways of hormone metabolism.embryo | endosperm | preharvest sprouting | testa S eed germination is completed by the emergence of the embryo from the seed coat (1), and plants have evolved a number of strategies to regulate germination. Seeds of many species go through dormancy, a period during which germination is suppressed under conditions that are normally favorable for germination (2). Dormancy allows seeds to germinate in appropriate seasons or at locations suitable for seedling growth and further development.

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Regulation of ABA and GA Levels During Seed Development and Germination inArabidopsis

Cited by 39 publications

References 94 publications

Melatonin improves the germination rate of cotton seeds under drought stress by opening pores in the seed coat

Melatonin improves the germination rate of cotton seeds under drought stress by opening pores in the seed coat

Transcription factor AtTCP14 regulates embryonic growth potential during seed germination in Arabidopsis thaliana

Induction of 9- cis -epoxycarotenoid dioxygenase in Arabidopsis thaliana seeds enhances seed dormancy

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