Endogenous ABA maintains shoot growth in tomato independently of effects on plant water balance: evidence for an interaction with ethylene

Sharp, Robert E.; LeNoble, Mary E.; Else, Mark A.; Thorne, E. Tom; Gherardi, Francesca

doi:10.1093/jexbot/51.350.1575

Cited by 277 publications

(209 citation statements)

References 39 publications

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“…3C). It is well characterized that ABA-deficient plants possess a small stature (42); this is a consequence of ABA's role in promoting shoot growth, which is thought to be partially mediated by repression of ethylene synthesis (43). Both exogenously applied ABA and quinabactin rescued the small stature of aba2 mutants to near WT levels (Fig.…”

Section: Resultsmentioning

confidence: 93%

Activation of dimeric ABA receptors elicits guard cell closure, ABA-regulated gene expression, and drought tolerance

Okamoto

Peterson

Defries

et al. 2013

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

279

268

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Abscisic acid (ABA) is an essential molecule in plant abiotic stress responses. It binds to soluble pyrabactin resistance1/PYR1-like/ regulatory component of ABA receptor receptors and stabilizes them in a conformation that inhibits clade A type II C protein phosphatases; this leads to downstream SnRK2 kinase activation and numerous cellular outputs. We previously described the synthetic naphthalene sulfonamide ABA agonist pyrabactin, which activates seed ABA responses but fails to trigger substantial responses in vegetative tissues in Arabidopsis thaliana. Here we describe quinabactin, a sulfonamide ABA agonist that preferentially activates dimeric ABA receptors and possesses ABA-like potency in vivo. In Arabidopsis, the transcriptional responses induced by quinabactin are highly correlated with those induced by ABA treatments. Quinabactin treatments elicit guard cell closure, suppress water loss, and promote drought tolerance in adult Arabidopsis and soybean plants. The effects of quinabactin are sufficiently similar to those of ABA that it is able to rescue multiple phenotypes observed in the ABA-deficient mutant aba2. Genetic analyses show that quinabactin's effects in vegetative tissues are primarily mediated by dimeric ABA receptors. A PYL2-quinabactin-HAB1 X-ray crystal structure solved at 1.98-Å resolution shows that quinabactin forms a hydrogen bond with the receptor/PP2C "lock" hydrogen bond network, a structural feature absent in pyrabactin-receptor/PP2C complexes. Our results demonstrate that ABA receptors can be chemically controlled to enable plant protection against water stress and define the dimeric receptors as key targets for chemical modulation of vegetative ABA responses.

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Section: Resultsmentioning

confidence: 93%

Activation of dimeric ABA receptors elicits guard cell closure, ABA-regulated gene expression, and drought tolerance

Okamoto

Peterson

Defries

et al. 2013

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

279

268

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“…S2) than those of the respective wild types. A reduction in organ size, including roots, of these mutants has previously been reported (Ran ci c et al, 2010;Sharp et al, 2000;Nitsch et al, 2012). genotypes were assessed using transmission electron microscopy (TEM).…”

Section: Aba Deficiency Leads To a Reduction In Plant And Organ Sizementioning

confidence: 90%

“…Indeed, in addition to its role in plant responses to water stress, ABA is also known to regulate many aspects of development, including the maintenance of shoot growth in well-watered plants (Sharp et al, 2000), the promotion of seed dormancy and the synthesis of seed storage proteins and lipids (Finkelstein et al, 2002). Consequently, a goal of this current study was to test the hypothesis that ABA is required for cuticle formation independent of water stress.…”

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confidence: 99%

Cuticle Biosynthesis in Tomato Leaves Is Developmentally Regulated by Abscisic Acid

et al. 2017

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The expansion of aerial organs in plants is coupled with the synthesis and deposition of a hydrophobic cuticle, composed of cutin and waxes, which is critically important in limiting water loss. While the abiotic stress-related hormone abscisic acid (ABA) is known to up-regulate wax accumulation in response to drought, the hormonal regulation of cuticle biosynthesis during organ ontogeny is poorly understood. To address the hypothesis that ABA also mediates cuticle formation during organ development, we assessed the effect of ABA deficiency on cuticle formation in three ABA biosynthesis-impaired tomato mutants. The mutant leaf cuticles were thinner, had structural abnormalities, and had a substantial reduction in levels of cutin. ABA deficiency also consistently resulted in differences in the composition of leaf cutin and cuticular waxes. Exogenous application of ABA partially rescued these phenotypes, confirming that they were a consequence of reduced ABA levels. The ABA mutants also showed reduced expression of genes involved in cutin or wax formation. This difference was again countered by exogenous ABA, further indicating regulation of cuticle biosynthesis by ABA. The fruit cuticles were affected differently by the ABA-associated mutations, but in general were thicker. However, no structural abnormalities were observed, and the cutin and wax compositions were less affected than in leaf cuticles, suggesting that ABA action influences cuticle formation in an organdependent manner. These results suggest dual roles for ABA in regulating leaf cuticle formation: one that is fundamentally associated with leaf expansion, independent of abiotic stress, and another that is drought induced.

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“…In the case of ABA-deficient mutant notabilis, results are in conflict with the recent report of reduced AM formation in the ABAdeficient tomato mutant sitiens (Herrera-Medina et al, 2007). Since ABA deficiency causes an elevation on ethylene production (Sharp et al, 2000), HerreraMedina et al (2007) provided evidence for a role of ethylene in AM formation using an exogenous inhibitor of this hormone action. The notabilis mutation used here is less drastic than sitiens, which presents a phenotype more characteristic of a severe ABA deficiency (e.g.…”

Section: Discussionmentioning

confidence: 99%

Reduced arbuscular mycorrhizal colonization in tomato ethylene mutants

Zsögön¹,

Lambais

Benedito³

et al. 2008

Sci. agric. (Piracicaba, Braz.)

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Plant hormones are likely key regulators of arbuscular mycorrhizae (AM) development. However, their roles in AM are not well known. Here mutants in five hormone classes introgressed in a single tomato (Lycopersicon esculentum Mill. Syn Solanum lycopersicum L.) background (cv. Micro-Tom) were used to determine their effects on AM development and the expression of defenserelated genes (chitinases and β-1,3-glucanases) in roots. Under low P conditions, mutant epinastic (epi) and Never ripe (Nr), ethylene overproducer and low sensitivity, respectively, had the intraradical colonization by Glomus clarum highly inhibited, as compared to the control Micro-Tom (MT). No significant alterations in fungal colonization were observed in mutants affecting other hormone classes. Under low P conditions, the steady state levels of transcripts encoding a class I basic chitinase (chi9) were higher in mycorrhizal epi and Nr mutant roots as compared to MT controls. In contrast the steady state levels of a class III acidic β-1,3-glucanase (TomPR-Q'a) transcripts in mycorrhizal epi mutant roots were significantly lower than in mycorrhizal MT roots. Root colonization in epi mutants was accompanied by several alterations in fungal morphology, as compared to root colonization in MT controls. The data suggest that ethylene may play an important role in controlling intraradical arbuscular mycorrhizal fungal growth. Key words: Lycopersicon, Micro-Tom, defense-related genes, hormones, phosphate REDUZIDA FORMAÇÃO DE MICORRÍZAS ARBUSCULARES EM TOMATEIROS MUTANTES EM ETILENORESUMO: Os hormônios vegetais são possíveis reguladores chave do desenvolvimento de micorrizas arbusculares (MAS). Contudo, seus papéis em MA são pouco conhecidos. No presente estudo, foram utilizados mutantes em cinco classes hormonais introgredidos em uma única cultivar (cv. MicroTom) de tomateiro (Lycopersicon esculentum Mill. Syn Solanum lycopersicum L.) para determinar seus efeitos no desenvolvimento de MA e expressão de genes relacionados à defesa (quitinases e β-1,3-glucanases) em raízes. Sob condição de baixo P, os mutantes epinastic (epi) e Never ripe (Nr), os quais são super produtores e pouco sensíveis a etileno, respectivamente, tiveram a colonização intraradicular por Glomus clarum inibida quando comparada com o controle Micro-Tom (MT). Não se observou alterações significativas na colonização fúngica nos mutantes afetando outras classes hormonais. Sob condição de baixo P, o nível de transcritos codificando uma quitinase básica de classe I (chi9) foi mais elevado em raízes micorrizadas dos mutantes epi e Nr, quando comparado com o controle MT. Em contraste, o nível de transcritos de uma β-1,3-glucanase ácida da classe III (TomPR-Q'a) em raízes micorrizadas do mutante epi foi significativamente menor que em raízes micorrizadas de MT. A colonização de raízes no mutante epi foi acompanhada por várias alterações na morfologia fúngica, quando comparada com o controle MT. Os resultados sugerem que o etileno pode desempenhar um importante papel controlando o c...

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Endogenous ABA maintains shoot growth in tomato independently of effects on plant water balance: evidence for an interaction with ethylene

Cited by 277 publications

References 39 publications

Activation of dimeric ABA receptors elicits guard cell closure, ABA-regulated gene expression, and drought tolerance

Activation of dimeric ABA receptors elicits guard cell closure, ABA-regulated gene expression, and drought tolerance

Cuticle Biosynthesis in Tomato Leaves Is Developmentally Regulated by Abscisic Acid

Reduced arbuscular mycorrhizal colonization in tomato ethylene mutants

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