Cell wall degradation is required for normal starch mobilisation in barley endosperm.
Cell wall degradation is required for normal starch mobilisation in barley endosperm.
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DOI：
10.1038/srep33215
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发表时间：
2016-09-13
影响因子：
4.6
通讯作者：
Smith AM
中科院分区：
文献类型：
--
作者：
Andriotis VM;Rejzek M;Barclay E;Rugen MD;Field RA;Smith AM
大麦胚乳中淀粉的降解为早期幼苗生长提供了碳源，但对这一过程的控制却知之甚少。我们研究了胚乳细胞壁降解是否是淀粉降解速率的重要决定因素。我们确定了亚氨基糖抑制剂的酶，降解细胞壁成分阿拉伯木聚糖。亚氨基糖1，4-二脱氧-1，4-亚氨基-1-阿拉伯糖醇（LAB）对阿拉伯木聚糖阿拉伯呋喃水解酶（AXAH）有抑制作用，但对淀粉主要降解酶α-淀粉酶、β-淀粉酶和极限糊精酶无抑制作用。胚乳中的AXAH活性在萌发开始后不久出现，并存在于含有两种亚型AXAH 1和AXAH 2的二聚体puppet中。在谷物吸胀时，阿拉伯木聚糖和淀粉的移动从糊粉层向折痕扩散穿过胚乳。阿拉伯木聚糖降解的前沿先于淀粉降解的前沿。用LAB孵育谷物降低了阿拉伯木聚糖和淀粉的损失率，并延缓了两种降解过程在胚乳中的传播。我们认为胚乳中淀粉的降解依赖于细胞壁的降解，细胞壁的降解使细胞壁透化，从而允许淀粉分解酶的快速扩散。AXAH在这方面可能特别重要。这些结果提供了新的见解动员胚乳储备，以支持早期幼苗生长。
Starch degradation in barley endosperm provides carbon for early seedling growth, but the control of this process is poorly understood. We investigated whether endosperm cell wall degradation is an important determinant of the rate of starch degradation. We identified iminosugar inhibitors of enzymes that degrade the cell wall component arabinoxylan. The iminosugar 1,4-dideoxy-1, 4-imino-l-arabinitol (LAB) inhibits arabinoxylan arabinofuranohydrolase (AXAH) but does not inhibit the main starch-degrading enzymes α- and β-amylase and limit dextrinase. AXAH activity in the endosperm appears soon after the onset of germination and resides in dimers putatively containing two isoforms, AXAH1 and AXAH2. Upon grain imbibition, mobilisation of arabinoxylan and starch spreads across the endosperm from the aleurone towards the crease. The front of arabinoxylan degradation precedes that of starch degradation. Incubation of grains with LAB decreases the rate of loss of both arabinoxylan and starch, and retards the spread of both degradation processes across the endosperm. We propose that starch degradation in the endosperm is dependent on cell wall degradation, which permeabilises the walls and thus permits rapid diffusion of amylolytic enzymes. AXAH may be of particular importance in this respect. These results provide new insights into the mobilization of endosperm reserves to support early seedling growth.
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影响因子：
9.4
作者：
Andriotis, Vasilios M. E.;Kruger, Nicholas J.;Smith, Alison M.
通讯作者：
Smith, Alison M.
影响因子：
4.1
作者：
AXAMAWATY, MTH;FLEET, GWJ;SINNOTT, ML
通讯作者：
SINNOTT, ML
DOI：
10.1007/bf02908044
发表时间：
1980-01-01
期刊：
CARLSBERG RESEARCH COMMUNICATIONS
影响因子：
--
作者：
GIBBONS, GC
通讯作者：
GIBBONS, GC
影响因子：
2.4
作者：
Kanauchi, M;Bamforth, CW
通讯作者：
Bamforth, CW
DOI：
10.1046/j.1432-1327.2000.01758.x
发表时间：
2000-11-01
期刊：
EUROPEAN JOURNAL OF BIOCHEMISTRY
影响因子：
--
作者：
Ferré, H;Broberg, A;Thomsen, KK
通讯作者：
Thomsen, KK