Starch Degradation in Endosperms of Developing Barley Kernels*

MacGregor, A. W.; Dushnicky, L.G.

doi:10.1002/j.2050-0416.1989.tb04638.x

Cited by 14 publications

(11 citation statements)

References 13 publications

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“…The disappearance of starch granules in this tissue strongly coincides with AMY enzyme activity (MacGregor and Dushnicky, 1989a). AMY enzyme activity was also detected in the embryo-surrounding region of the endosperm (MacGregor and Dushnicky, 1989b). BAM enzyme activity was measured in the barley endosperm at later developmental stages (Beck and Ziegler, 1989).…”

mentioning

confidence: 63%

Spatiotemporal Profiling of Starch Biosynthesis and Degradation in the Developing Barley Grain

Borisjuk²,

et al. 2009

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Barley (Hordeum vulgare) grains synthesize starch as the main storage compound. However, some starch is degraded already during caryopsis development. We studied temporal and spatial expression patterns of genes coding for enzymes of starch synthesis and degradation. These profiles coupled with measurements of selected enzyme activities and metabolites have allowed us to propose a role for starch degradation in maternal and filial tissues of developing grains. Early maternal pericarp functions as a major short-term starch storage tissue, possibly ensuring sink strength of the young caryopsis. Gene expression patterns and enzyme activities suggest two different pathways for starch degradation in maternal tissues. One pathway possibly occurs via a-amylases 1 and 4 and b-amylase 1 in pericarp, nucellus, and nucellar projection, tissues that undergo programmed cell death. Another pathway is deducted for living pericarp and chlorenchyma cells, where transient starch breakdown correlates with expression of chloroplast-localized b-amylases 5, 6, and 7, glucan, water dikinase 1, phosphoglucan, water dikinase, isoamylase 3, and disproportionating enzyme. The suite of genes involved in starch synthesis in filial starchy endosperm is much more complex than in pericarp and involves several endosperm-specific genes. Transient starch turnover occurs in transfer cells, ensuring the maintenance of sink strength in filial tissues and the reallocation of sugars into more proximal regions of the starchy endosperm. Starch is temporally accumulated also in aleurone cells, where it is degraded during the seed filling period, to be replaced by storage proteins and lipids.

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confidence: 63%

Spatiotemporal Profiling of Starch Biosynthesis and Degradation in the Developing Barley Grain

Borisjuk²,

et al. 2009

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“…The relationship between enzymatic activity and breadmaking quality It has been reported that the increases of ␣-amylase and endo-protease activities in wheat are related to the degradation of flour (Jones & Wrobel, 1993;MacGregor & Matsuo, 1972;MacGregor & Dushnicky, 1989;Prestone & Kruger, 1979). However, the relationship between the enzymatic activities and the breadmaking quality of wheat during germination is not always clear.…”

Section: Germination Effect On Breadmaking Qualitymentioning

confidence: 99%

“…and is unsuitable for industrial processing. Many studies on germination damage in wheat deal with starch degradation, i.e., MV of Amylograph, Falling number, ␣-amylase activity and the quality of bread (MacGregor & Matsuo, 1972; Meredith & Pomernz, 1985;MacGregor & Dushnicky, 1989). However, the deterioration of breadmaking quality in flour that has been damaged during sprouting cannot always be explained by low MV values (Yamauchi et al, 1998;Sato et al, 1999).…”

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confidence: 99%

Effects of Increase in .ALPHA.-Amylase and Endo-Protease Activities during Germination on the Breadmaking Quality of Wheat.

Ichinose

Takata

Kuwabara

et al. 2001

FSTR

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The effects of increase in ␣-amylase and endo-protease activities during germination on the deterioration of the breadmaking quality of hard wheat were examined using three varieties with different strengths of gluten: VictoriaINTA, Harunoakebono, and Leader. The results are summarized as follows: (1) The degradation of the breadmaking quality of flour damaged in germination differed greatly according to the gluten strength of each variety. VictoriaINTA, which has extra-strong gluten, was more tolerant of the germination damage than the other varieties with strong gluten. (2) The degradation of specific loaf volume, which is caused by lowering the gas retention of the dough, was the result of the softening of the dough that was observed as a decrease in the mixing peak time and the breaking force of the dough. (3) The ␣-amylase and endo-protease activities of flours did not seemed to influence the breadmaking quality, although there was a considerably high correlation between endo-protease activity of whole wheat flour and breadmaking quality. From these results, it would seem that the main reason that flour damaged during germination degrades breadmaking quality is the endo-protease in the wheat grain, which already causes partial gluten decomposition. Accordingly, it might be better to examine the endo-protease activity of whole wheat flour at harvest ripeness in order to estimate the value of breadmaking quality within the hard-wheat breeding system. Keywords: extra-strong variety, breadmaking quality, endo-protease activity, ␣-amylase activity Most Japanese hard wheat used for bread is grown in Hokkaido; however, pre-harvest sprouting often occurs as grain develops due to unfavorable weather. This problem is serious because wheat flour that is damaged during germination has a maximum viscosity (MV) of Amylograph that is below 300 B.U. and is unsuitable for industrial processing. Many studies on germination damage in wheat deal with starch degradation, i.e., MV of Amylograph, Falling number, ␣-amylase activity and the quality of bread (MacGregor & Matsuo, 1972; Meredith & Pomernz, 1985;MacGregor & Dushnicky, 1989). However, the deterioration of breadmaking quality in flour that has been damaged during sprouting cannot always be explained by low MV values (Yamauchi et al., 1998;Sato et al., 1999). Therefore, another practical index to estimate the value of breadmaking quality is required within the hard-wheat breeding system. On the other hand, there is some evidence that the degradation of storage protein also greatly contributes to the loss of breadmaking quality during germination. (Kruger, 1971;Bushuk & Lukow, 1987;Lukow & Bushuk, 1984;Janssen et al., 1996b;Weegels et al.,1996). Studies show that an increase in ␣-amylase and endoprotease activities in wheat may lead to degradation of endosperm starch and protein during germination and may have a deleterious effect on the quality of bread (Kiribuchi & Nakamura, 1973; Preston & Kruger, 1979;Meredith & Pomeranz, 1985;Salomonsson et al., 1989; Sun & Henson,19...

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“…The flour of the grains damaged by pre-harvest sprouting has a maximum viscosity (MV) in amylography below 300 BU and is unsuitable for industrial processing. Many studies have shown that endosperm starch degraded by a-amylase activity may adversely affect the quality of flour for noodles (Yasunaga et al, 1963;MacGregor and Matsuo, 1972;MacGregor and Dushnicky, 1989;Salomonsson et al, 1989;Matsuzaki and Toyoda, 1996). The degradation of endosperm protein caused by endoprotease may greatly contribute to the deterioration in bread-making quality (Preston et al, 1978;Lukow et al, 1984;Janssen et al, 1996;Weegels et al, 1996).…”

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confidence: 99%

Germination of Wheat Grains at Various Temperatures in Relation to the Activities of α-Amylase and Endoprotease

Ichinose

Kuwabara

Hakoyama

2002

Plant Production Science

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Starch Degradation in Endosperms of Developing Barley Kernels*

Cited by 14 publications

References 13 publications

Spatiotemporal Profiling of Starch Biosynthesis and Degradation in the Developing Barley Grain

Spatiotemporal Profiling of Starch Biosynthesis and Degradation in the Developing Barley Grain

Effects of Increase in .ALPHA.-Amylase and Endo-Protease Activities during Germination on the Breadmaking Quality of Wheat.

Germination of Wheat Grains at Various Temperatures in Relation to the Activities of α-Amylase and Endoprotease

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