Development of<i>β</i>-amylase activity and polymorphism in wheat seedling shoot tissues8

Ziegler, Paul; Daussant, J.; Loos, Karin

doi:10.1093/jxb/45.8.1147

Cited by 16 publications

(6 citation statements)

References 15 publications

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“…β-Amylase is an exohydrolase that can remove maltose residues from the nonreducing end of α-(1→4) glucan chains. The enzyme activity of β-amylase in germinating cereal grains increases in parallel to that of α-amylase and is found in several isoforms in the endosperm; for example there are three in wheat (Zeigler et al 1994). Unlike α-amylase, β-amylase is produced in large amounts during endosperm development.…”

Section: Figurementioning

confidence: 99%

Germination of Wheat: A Functional Proteomics Analysis of the Embryo

et al. 2009

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Cereal Chem. 86(3):281-289Germination in the soft wheat (Triticum aestivum L.) cultivar Rosella was followed for three days after imbibition by proteomic analysis of the germ tissue. Two-dimensional electrophoresis was performed in triplicate for proteins extracted from embryos dissected from mature grain and from grains germinated for 1, 2, and 3 days. For this period, 63 proteins (in 86 spots) in the germ were identified as decreasing in abundance, 35 proteins (in 60 spots) as increasing in abundance, and 28 proteins (in 39 spots) as exhibiting no significant abundance change. Proteins with significant abundance changes are discussed in relation to physiology; these include proteases, amylases and amylase inhibitors, enzymes in lipid metabolism, proteins related to water stress, cell wall hydrolases, oxalate oxidase, and H + -ATPases. Functions associated with proteins synthesized during the germination period are inconsistent with the embryo of mature grain being fully primed for germination.Germination involves reanimation of the embryo from a state of quiescence in mature seed to a state of highly active metabolism. Germination is triggered by rehydration at a temperature within an acceptable range, and requires adequate rates of gas exchange. In grasses such as wheat, abundant stores of starch and protein are contained in the starchy endosperm, which loses its cellular structure as grains reach maturity, but is surrounded by a layer of intact aleurone cells. Breakdown of storage carbohydrates and proteins occurs during germination to provide nutrition for the rapidly growing embryo before autotrophy can begin.An extensive literature describes the storage proteins of the wheat endosperm, their variation between cultivars, and their influence on flour quality (see review in Singh et al [2005]). Many aspects of the biochemistry and control of storage protein (and starch) breakdown are well understood for wheat and other monocotyledonous cereals. In the earliest stage of germination, imbibition results in the synthesis of gibberellic acid (GA) by the embryo. This hormone acts to promote expression of genes for hydrolytic enzymes produced in the aleurone and scutellum. In the embryo, repair and synthesis of mitochondria and activation of respiration allows mobilization of the embryo's internal reserves of proteins, lipids, and carbohydrates.In this study, we focus on proteomic changes in the embryo that occur throughout the germination period, a relatively unexplored area. We aim to further our understanding of metabolic changes occurring during germination by correlating changes in protein abundance with physiological processes associated with germination and very early seedling development. Many questions concerning the role and status of proteins in the wheat embryo during germination remain unresolved. For example, to what extent is the embryo of the mature grain primed for germination? What types of proteins required for germination are synthesized during grain development or after imbibition? To what exten...

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Section: Figurementioning

confidence: 99%

Germination of Wheat: A Functional Proteomics Analysis of the Embryo

et al. 2009

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“…This shortening in the phase of enzyme development may explain the markedly (p < .001) lower ␤-amylase values associated with the green (acetone-dried) malts in comparison to values for corresponding malts dried at 40°C. On the other hand, post-translational activation by proteases has been associated with improved ␤-amylase activity during cereal grain malting 12,13,16,31,35 . Thus in addition to probable de novo ␤-amylase synthesis 17 , possible proteolytic activation of ␤-amylase zymogens during the enzymic phase of malt kilning 17 may in part account for the higher ␤-amylase levels observed in 40°C-dried grains as compared to values for the green malts.…”

Section: Xiit Pmuysv Gliqmgep Gsqtswmxmsr Erh Qepx Beq]pewi Egxmzmx]mentioning

confidence: 99%

Sorghum β-Amylase Production: Relationship With Grain Cultivar, Steep Regime, Steep Liquor Composition and Kilning Temperature

Okungbowa

Obeta

Ezeogu

2002

Journal of the Institute of Brewing

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Steep regime, nature of alkaline liquor, and kilning conditions were studied for their effects on sorghum malt ␤-amylase development in four Nigerian sorghum cultivars. Malt ␤-amylase activity was markedly (p < .001) influenced by all the four factors as well as their various interactions. Overall, malts from KSV 8 variety were the most ␤-amylolytic followed in sequence by those from Local Red (LR), SK 5912, and Local white (LW) respectively. The presence or absence of air rests in steep regimes was a significant (p < .001) determinant of sorghum ␤-amylase response to final warm steeping, steep liquor and kilning condition. The nature of the alkaline steep liquor was also a major determinant of the pattern of malt ␤-amylase response to the kilning condition. Steeping in Ca(OH) 2 enhanced malt ␤-amylase activity at the higher temperature of kilning, while KOH produced the opposite effect. Ca(OH) 2 enhancement of ␤-amylase development, at a kilning temperature of 50°C, was varietydependent suggesting that different sorghum cultivars may employ different biosynthesis models for ␤-amylase synthesis. The regime-dependence of ␤-amylase response to kiln temperature suggests that this was an important modulator of sorghum germination physiology.Key words: Alkaline liquor, ␤-amylase, kilning temperature, sorghum malt, steeping regime, cultivars. -2863(9'8-32␤-Amylase is the key saccharifying enzyme of the brewers' malt 22 . While the low ␤-amylase activity of sorghum malts has been defined as one of the most serious obstacles to its use as replacement for barley malt 2 , results of recent studies using some improved varieties of the grain suggest that the production of high ␤-amylasecontaining sorghum malts may be possible with the proper choice of variety and conditions of malting 9,10,[25][26][27] . Recent research has shown that sorghum malt ␣-amylase level is critically correlated with environmental conditions of steeping and kilning 24 . While some work has been conducted on the effects of environmental conditions of steeping on sorghum malt ␤-amylase levels, very few data are available with respect to the effects of kilning conditions on the development of the sorghum enzyme 29 . In this communication, we present the effects of kilning conditions on the ␤-amylase activity of sorghum malts prepared from different cultivars, and under varying conditions of steeping including dissimilar steep liquors as well as different steeping regimes. 1%8)6-%07 %2( 1)8,3(7 7SYVGIW SJ WSVKLYQ GYPXMZEVWCultivars SK 5912 and KSV 8 were improved varieties obtained from the National Seeds Service, Zaria, Nigeria. Grains of the local white (LW) and the local red (LR) varieties were purchased from the open market at Nsukka, Nigeria. Germinative energies were above 95% for all the grains and none was water-sensitive. 7SVKLYQ QEPXMRKThe grains were sorted manually to remove broken kernels and debris. Alkaline steeping was carried out using glass-distilled water containing 0.1% of the alkali (NaOH, KOH, or Ca(OH) 2 ). Double glass-distilled...

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“…β‐Amylase2 from wheat leaves is composed of five isoforms (Wagner et al, 1999; Zemanova et al, 2002; Ziegler et al, 1994, 1997). These isoforms were derived from a single, full‐length enzyme that underwent posttranslational proteolytic processing at the C‐terminal end to generate smaller isoforms (Wagner et al, 1999; Zemanova et al, 2002; Ziegler et al, 1997).…”

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Characterization of Barley Tissue‐Ubiquitous β‐Amylase2 and Effects of the Single Nucleotide Polymorphisms on the Enzyme's Thermostability

2005

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with enhanced thermostability or to create such enzymes via mutagenesis (Clark et al., 2003; There are two barley (Hordeum vulgare L.) ␤-amylase genes en- al., 1998; Gunkel et al., 2002; Kaneko et al., 2001; Kihara coding important starch-degrading enzymes. The endosperm-specific et al., 1998; Ma et al., 2000aMa et al., , 2001 Yoshigi et al., 1995).␤-amylase (Bmy1), the more abundant isozyme in cereal seeds, has been thoroughly characterized. The lesser abundant There are at least two genes encoding ␤-amylases in has not been biochemically characterized from any cereal seeds. Char- barley (Kreis et al., 1987barley (Kreis et al., , 1988. The bmy1 gene located acterization of Bmy2 from two commonly grown barley cultivars, on chromosome 4H encodes ␤-amylase1 (Bmy1), an Morex and Steptoe, was a major objective of this study. The bmy2 enzyme unique to the endosperm tissue in the seeds of cDNAs were sequenced, expressed in Escherichia coli, and the recomthe Triticeae family of cereals [barley, wheat (Triticum binant enzymes (rBmy2) characterized. The relative hydrolysis rates aestivum L.), and rye (Secale cereale L.)] (Daussant et of various ␣-D-glucans and the pH activity optima of Morex and al., 1994; Kreis et al., 1988). Barley Bmy1 is well charac-Steptoe rBmy2s were the same and not significantly different from terized due to its involvement in the starch degradation barley rBmy1. The Morex rBmy2 was 7؇C more thermostable than pathway that is the basis of the brewing industry (Allison the Steptoe rBmy2, determined by differences in their T 50 values, and and Swanston , 1974; Clark et al., 2003; Hejgaard, 1976; is more thermostable than any reported wild-type ␤-amylase1. Three amino acid differences were identified between the two Bmy2 se- Kreis et al., 1987;Lauriere et al., 1986; Lundgard and quences and the contributions to enzyme thermostability evaluated Svensson, 1987; Ma et al., 2000aMa et al., , 2000b; Nishimura et by site-directed mutagenesis. Examination of mutant enzymes with al., 1987;. The ␤-amylase2 (bmy2) gene, one amino acid substitution revealed that each of the three residues located on chromosome 2H (Kreis et al., 1988), encodes contributed ≈3؇C to the thermostability of the Morex wild-type rBmy2. ␤-amylase2 (Bmy2) that is present in all cereal plantsMutant enzymes with two amino acid substitutions contributed ≈5.6؇C, and has been termed "ubiquitous ␤-amylase" (Daussant and the triple amino acid mutant enzyme contributed ≈8.7؇C to ther- et al., 1991, 1994). Shewry et al. (1988) showed that, in mostability. To date, no quantitative trait loci (QTL) for malting barley, a ␤-amylase isozyme was expressed in all tissues quality traits have been associated with the bmy2 locus. Should an tested, hence ubiquitous, and was distinct from the enassociation be discovered, the Morex bmy2 allele, containing D238, dosperm-specific ␤-amylase that arises during seed de-M337, and Q362, provides a discrete signature of a thermostable ␤-amylase2 that could be targeted for marker assisted selection.

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Development ofβ-amylase activity and polymorphism in wheat seedling shoot tissues8

Cited by 16 publications

References 15 publications

Germination of Wheat: A Functional Proteomics Analysis of the Embryo

Germination of Wheat: A Functional Proteomics Analysis of the Embryo

Sorghum β-Amylase Production: Relationship With Grain Cultivar, Steep Regime, Steep Liquor Composition and Kilning Temperature

Characterization of Barley Tissue‐Ubiquitous β‐Amylase2 and Effects of the Single Nucleotide Polymorphisms on the Enzyme's Thermostability

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