CYP707A3, a major ABA 8′‐hydroxylase involved in dehydration and rehydration response in <i>Arabidopsis thaliana</i>

Umezawa, Taishi; Okamoto, Masanori; Kushiro, Toshio; Nambara, Eiji; Oono, Youko; Seki, Motoaki; Kobayashi, Masatomo; Koshiba, Tomokazu; Kamiya, Yûji; Shinozaki, Kazuo

doi:10.1111/j.1365-313x.2006.02683.x

Cited by 287 publications

(222 citation statements)

References 40 publications

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“…The localization of SlCYP707A1 mRNA is comparable to the localization of the hormone ABA in the ovules of Arabidopsis and cucumber (Peng et al 2006). The decrease in mRNA levels of the three other putative tomato CYP707A genes might be explained by the reduction in ABA concentration, since positive feedback from ABA on CYP707A expression has been found in Arabidopsis (Kushiro et al 2004;Umezawa et al 2006), potato (Destefano-Beltran et al 2006) and by us in tomato (Fig. 6b).…”

Section: Regulation Of Aba Biosynthesis and Catabolismsupporting

confidence: 51%

Abscisic acid levels in tomato ovaries are regulated by LeNCED1 and SlCYP707A1

Nitsch

Oplaat

Feron

et al. 2009

Planta

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Although the hormones, gibberellin and auxin, are known to play a role in the initiation of fruits, no such function has yet been demonstrated for abscisic acid (ABA). However, ABA signaling and ABA responses are high in tomato (Solanum lycopersicum L.) ovaries before pollination and decrease thereafter (Vriezen et al. in New Phytol 177:60-76, 2008). As a Wrst step to understanding the role of ABA in ovary development and fruit set in tomato, we analyzed ABA content and the expression of genes involved in its metabolism in relation to pollination. We show that ABA levels are relatively high in mature ovaries and decrease directly after pollination, while an increase in the ABA metabolite dihydrophaseic acid was measured. An important regulator of ABA biosynthesis in tomato is 9-cis-epoxy-carotenoid dioxygenase (LeNCED1), whose mRNA level in ovaries is reduced after pollination. The increased catabolism is likely caused by strong induction of one of four newly identiWed putative (+)ABA 8Ј-hydroxylase genes. This gene was named SlCYP707A1 and is expressed speciWcally in ovules and placenta. Transgenic plants, overexpressing SlCYP707A1, have reduced ABA levels and exhibit ABA-deWcient phenotypes suggesting that this gene encodes a functional ABA 8Ј-hydroxylase. Gibberellin and auxin application have diVerent eVects on the LeNCED1 and SlCYP707A1 gene expression. The crosstalk between auxins, gibberellins and ABA during fruit set is discussed.

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Section: Regulation Of Aba Biosynthesis and Catabolismsupporting

confidence: 51%

Abscisic acid levels in tomato ovaries are regulated by LeNCED1 and SlCYP707A1

Nitsch

Oplaat

Feron

et al. 2009

Planta

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“…The knockout mutant of UGT71B6 did not give any noticeable phenotype, and UGT71B6 overexpression had a marginal effect on reducing the ABA content (Priest et al, 2006). By contrast, overexpression of CYP707A3, one of four P450 hydroxylases involved in 89-hydroxylation of ABA in Arabidopsis, significantly reduces endogenous ABA levels (Millar et al, 2006;Umezawa et al, 2006). In this report, we provide evidence that UGT71B6 and its two closely related homologs, UGT71B7 and UGT71B8, play important roles in modulating cellular ABA levels.…”

mentioning

confidence: 59%

“…However, overexpression of UGT71B6 in Arabidopsis does not cause a significant ABA-deficient phenotype. By contrast, overexpression of CYP707A3 significantly lowers the cellular ABA levels and results in a clear ABA-deficient phenotype (Umezawa et al, 2006). This suggests that hydroxylation is the major pathway for ABA inactivation in plant cells.…”

mentioning

confidence: 79%

Abscisic Acid Uridine Diphosphate Glucosyltransferases Play a Crucial Role in Abscisic Acid Homeostasis in Arabidopsis

Park

Kim

et al. 2014

Plant Physiol.

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The phytohormone abscisic acid (ABA) is crucial for plant growth and adaptive responses to various stress conditions. Plants continuously adjust the ABA level to meet physiological needs, but how ABA homeostasis occurs is not fully understood. This study provides evidence that UGT71B6, an ABA uridine diphosphate glucosyltransferase (UGT), and its two closely related homologs, UGT71B7 and UGT71B8, play crucial roles in ABA homeostasis and in adaptation to dehydration, osmotic stress, and high-salinity stresses in Arabidopsis (Arabidopsis thaliana). UGT RNA interference plants that had low levels of these three UGT transcripts displayed hypersensitivity to exogenous ABA and high-salt conditions during germination and exhibited a defect in plant growth. However, the ectopic expression of UGT71B6 in the atbg1 (for b-glucosidase) mutant background aggravated the ABA-deficient phenotype of atbg1 mutant plants. In addition, modulation of the expression of the three UGTs affects the expression of CYP707A1 to CYP707A4, which encode ABA 89-hydroxylases; four CYP707As were expressed at higher levels in the UGT RNA interference plants but at lower levels in the UGT71B6:GFP-overexpressing plants. Based on these data, this study proposes that UGT71B6 and its two homologs play a critical role in ABA homeostasis by converting active ABA to an inactive form (abscisic acid-glucose ester) depending on intrinsic cellular and environmental conditions in plants.

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“…In general, the drought response pathways can be classified into two categories: one is dependent on the stress hormone ABA and the other is ABA independent (Umezawa et al 2006b). ABA-responsive elements (ABRes) are one of the main cis-acting elements in ABA-dependent signaling of water stress responses (Shinozaki and YamaguchiShinozaki 2007).…”

Section: Transcription Factors and Droughtmentioning

confidence: 99%