The effect of external ph on the gibberellic acid response of barley aleurone

Sinjorgo, K. M. C.; Vries, M.A. de; Heistek, Jolanda C.; Zeijl, Mieke J. van; Veen, Simone W. van der; Douma, A.C.

doi:10.1016/s0176-1617(11)81260-5

Cited by 19 publications

(12 citation statements)

References 10 publications

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“…The a-amylase/subtilisin inhibitor forms a complex with a-amylase at neutra1 or basic pH values and dissociates at acidic pH values (Halayko et al, 1986). Low extracellular pH may also be essential for the response of the aleurone layer to GA, and ABA by favoring hormone uptake or the interaction of GA, and ABA with receptors (Sinjorgo et al, 1993). …”

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confidence: 99%

Hormonal Regulation of Organic and Phosphoric Acid Release by Barley Aleurone Layers and Scutella

Drozdowicz

Jones

1995

Plant Physiol.

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The release of acid from the aleurone layer and scutellum of barley (Hordeum vulgare L. cv Himalaya) was investigated. Aleurone layers isolated from mature barley grains acidify the external medium by releasing organic and phosphoric acids. Cibberellic acid and abscisic acid stimulate acid release 2-fold over control tissue incubated in 10 mM CaCI,. Cibberellic acid causes medium acidification by stimulating the release of phosphoric and citric acids, whereas abscisic acid stimulates the release of malic acid. The accumulation of these acids in the incubation medium buffers the medium against changes in pH, particularly between pH 4 and 5. The amounts of amino acids that accumulate in the medium are low (2-1 2 nmol/layer) compared to other organic and phosphoric acids (100-500 nmol/layer). The scutellum does not play a major role in medium acidification but participates in the uptake of organic acids. The organic acid composition of the starchy endosperm changes after 3 d of imbibition; malic, succinic, and lactic acids decrease, whereas citric and phosphoric acids remain unchanged or increase. These results indicate that during postgerminative growth, the acidity of the starchy endosperm is maintained by acid production by the aleurone layer.

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confidence: 99%

Hormonal Regulation of Organic and Phosphoric Acid Release by Barley Aleurone Layers and Scutella

Drozdowicz

Jones

1995

Plant Physiol.

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“…The biological activity of GA is known to be affected by pH and is greater at pHs that favour association of the C‐7 carboxyl group ( Greenberg & Goldschmidt 1989;Hamabata et al . 1994 ;Sinjorgo et al . 1993 ;Tidd 1964).…”

Section: Discussionmentioning

confidence: 99%

Gibberellin‐photoaffinity labelling of two polypeptides in plant plasma membranes

et al. 1998

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SummaryTwo polypeptides of M r 68 kDa and 18 kDa were gibberellin (GA)-photoaffinity labelled in vitro in plasma membrane preparations from oat (Avena sativa L.) aleurone and from leaves and stems of wild-type and GA-sensitivity mutants of different species. Labelling of these polypeptides could be competed by biologically active, but not by inactive, GAs, indicating the likely biological significance of these interactions. On 2-dimensional gels the radiolabelled polypeptides were each resolved as one intensely labelled low abundance spot with a slightly lower pI form adjacent to it. There was a strong pH dependency for both labelling events, which correlated well with pH values at which GA are known to be most biologically active. A semi-dwarf GAsensitivity mutant of sweet pea (Lathyrus odoratus L.), lb, showed reduced photoaffinity labelling of both polypeptides compared with the wild type, Lb. In the GA-insensitive Arabidopsis thaliana mutant, gai, the level of labelling was the same as in wild type, GAI. This is the first report of GA-binding proteins in plant plasma membranes. Some preliminary sequence data are given for one of the labelled polypeptides. We discuss these mutants and consider their possible roles in GA perception or action.

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“…Therefore increased GA responsiveness as extracellular pH was lowered would suggest an internal receptor site. These early experiments provided evidence for both internal and external perception sites (Goodwin & Carr, 1972 ;Sinjorgo et al, 1993 ;Smith et al, 1993 ;Hamabata et al, 1994). However, several factors other than a pH-dependent change in GA permeability might have affected these results.…”

Section:       mentioning

confidence: 96%

Gibberellins: regulating genes and germination

Ritchie

Gilroy

1998

New Phytologist

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The range of processes regulated by gibberellins (GAs) covers all aspects of the life history of the plant from seed germination to vegetative growth and flowering. In seeds there has been an intensive search, using the techniques of both biochemistry and cell biology, for the regulatory molecules linking GA perception to gene regulation and the events of germination. Although a GA receptor has yet to be identified, the site of perception has been localized to the plasma membrane. Calmodulin, Ca2+ and cGMP have also been identified as elements of the GA signal transduction pathway. These regulators parallel many of the signalling elements identified in the transduction of other signals such as phytochrome and ABA. Studies of GA‐regulated gene expression, principally of the α‐amylases of cereal aleurone, have identified core GA‐responsive promoter elements, such as the gibberellin response element (GARE), box‐1 and pyrimidine boxes, as well as elements that may lend specificity to GA‐regulated expression, such as the Opaque‐2‐similar element (O2S), and TRE and CRE motifs. One of the most striking features of all of these studies of the molecular basis of GA action is the interaction of GA‐dependent regulatory elements with those of other factors such as ABA. GA‐response elements also appear to be conserved between disparate GA‐response systems. For example, Myb transcription factors appear to regulate a multitude of GA‐induced genes in cereal aleurone as well as to alter GA responses when expressed in Arabidopsis. Thus the study of GA signal transduction and response systems is highlighting the conservation of regulatory elements used by plants. These common factors, used by distinct signal transduction systems, provide a molecular basis for the integration of the GA signal with other growth regulators that is the hallmark of plant growth and development.

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The effect of external ph on the gibberellic acid response of barley aleurone

Cited by 19 publications

References 10 publications

Hormonal Regulation of Organic and Phosphoric Acid Release by Barley Aleurone Layers and Scutella

Hormonal Regulation of Organic and Phosphoric Acid Release by Barley Aleurone Layers and Scutella

Gibberellin‐photoaffinity labelling of two polypeptides in plant plasma membranes

Gibberellins: regulating genes and germination

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