Gibberellic Acid (GA 3 )-Induced Enhancement of α-Amylase Activity in the Aleurone of Shrunken-2 Maize Kernels

Sanwo, Monica M.; DeMason, Darleen A.

doi:10.2307/2445292

Cited by 6 publications

(3 citation statements)

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“…The lesion in this mutant is in a gene involved in the formation of complex carbohydrates and results in the endosperm containing more simple sugars than normal starchy lines. While activation of amylase genes from the wild-type maize aleurone is GA independent, exogenous application of GA is required to restore normal levels of amylase production in the sh-2 mutant (Sanwo and DeMason, 1994).…”

Section: Role Of the Starchy Endosperm During Germination And Early Smentioning

confidence: 99%

Physiology of the aleurone layer and starchy endosperm during grain development and early seedling growth: new insights from cell and molecular biology

2000

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Cereal grain germination and early seedling growth involve the co-ordinated action of endosperm and embryo tissues to mobilize the storage reserves of the starchy endosperm. This mobilization is accomplished by hydrolases secreted from the aleurone and scutellar tissues. The breakdown products are then transported to the growing seedling by the scutellum. This resource-harvesting system is regulated at multiple levels. One well-defined aspect of control is brought about by the hormone gibberellin (GA). Gibberellin is released from the embryo upon imbibition and activates the aleurone cells. The secretory apparatus of the aleurone then proliferates, supporting increased hydrolase synthesis and secretion to degrade the starchy endosperm. The molecules that regulate this response to GA are now being increasingly characterized. Elements such as cGMP, calcium, calmodulin and protein kinases are well known as regulators in other eukaryotic cell types and are emerging as key control factors in the aleurone hormone response. However, superimposed upon this molecular regulatory system is another level of control, the structural pattern of tissues and stored macro- molecules that was laid down during grain development. It is the interaction of these structural motifs combined with the molecular regulatory mechanisms that ensure the appropriate timing and positioning of hydrolase production and endosperm reserve mobilization. This integrated control system ensures an extended release of nutrients to fuel early seedling growth.

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Section: Role Of the Starchy Endosperm During Germination And Early Smentioning

confidence: 99%

Physiology of the aleurone layer and starchy endosperm during grain development and early seedling growth: new insights from cell and molecular biology

2000

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“…The maize shrunken-2 (sh-2 ) line (Sanwo & DeMason, 1994) also indicates a complex interaction between the GA and sugar signal systems. The regulation of α-amylase gene expression in maize aleurone is generally regarded as being GAindependent.…”

Section: Transcriptional Regulationmentioning

confidence: 99%

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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“…No entanto, poucos trabalhos são realizados com o objetivo de se definir a expressão do gene de α-amilase em sementes de milho (Mundy et al, 1985;Sanwo & Demason, 1993;1994;Sachs et al, 1996). O presente trabalho teve como objetivo padronizar a metodologia da técnica do RT-PCR utilizada na identificação do mRNA produzido a partir do gene de α-amilase durante a germinação de sementes de milho.…”

Section: Introductionunclassified

Padronização da metodologia do RT-PCR utilizado para identificação do mRNA da a-amilase em sementes de milho

Dantas¹,

Aragão²,

Araújo-Junior³

et al. 2002

Rev. bras. sementes

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C por 5 minutos. O produto do RT-PCR apresentou uma banda de 249 pares de base (pb) bem definida, para as duas cultivares estudadas, não ocorrendo bandas inespecíficas. A técnica do RT-PCR mostrou ser uma metodologia eficiente para a identificação da expressão de α-amilase durante a germinação das sementes e pode ser usado para estudo qualitativo e quantitativo da cinética de síntese dessa enzima em experimentos de germinação.Termos para indexação: Zea mays, sementes, α-amilase, RT-PCR. RT-PCR PATTERNING FOR α-AMYLASE MESSENGER RNA IDENTIFICATION IN GERMINATING MAIZE SEEDSABSTRACT -During germination the seed reserve carbohydrates are degraded by α-amylase activity. The identification of mRNA is a very important tool for definition of α-amylase synthesis kinetics. This study aimed to adapt a PT-PCR methodology for α-identification of amylase mRNA in germinating maize seeds. After three days germination of Saracura BRS4154 and CATI AL34 maize cultivars, the total RNA was isolated by the guanidinium thiocyanate-phenol-chloroform extraction method, with some modifications. The cDNA was obtained from the total RNA, using random primers. The α-amylase gene PCR amplification was carried out with cDNA, primers (sense -CGACATCGACCACCTCAAC; antisense -TTGACCAGCTCCTGCCTGTC); gelatina; DMSO and 1,25 units of Taq

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Gibberellic Acid (GA 3 )-Induced Enhancement of α-Amylase Activity in the Aleurone of Shrunken-2 Maize Kernels

Cited by 6 publications

References 0 publications

Physiology of the aleurone layer and starchy endosperm during grain development and early seedling growth: new insights from cell and molecular biology

Physiology of the aleurone layer and starchy endosperm during grain development and early seedling growth: new insights from cell and molecular biology

Gibberellins: regulating genes and germination

Padronização da metodologia do RT-PCR utilizado para identificação do mRNA da a-amilase em sementes de milho

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