Development and Quality of Barley Husk Adhesion Correlates With Changes in Caryopsis Cuticle Biosynthesis and Composition
Development and Quality of Barley Husk Adhesion Correlates With Changes in Caryopsis Cuticle Biosynthesis and Composition
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DOI：
10.3389/fpls.2019.00672
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发表时间：
2019-05-24
影响因子：
5.6
通讯作者：
Hoad, Stephen P.
中科院分区：
文献类型：
--
作者：
Brennan, Maree;Hedley, Pete E.;Hoad, Stephen P.
大麦的颖果在籽粒发育过程中通过颖果表面的角质层粘合而牢固地粘附在谷壳上。这种附着的程度因品种而异，质量差的附着导致“结皮”，这是麦芽制造业的一种经济上重要的谷物质量缺陷。麦芽栽培品种涵盖了一系列的外壳粘附质量下生长的雾化处理已知诱导剥皮。通过电子显微镜检查胶结层的发展，并用气相色谱法和质谱法研究胶结层的组成变化。用定制的大麦微阵列检查粘附发育过程中基因表达的变化。丰富的转录参与表皮脂质生物合成的早期，包括那些编码乙酰辅酶A羧化酶，和所有四个成员的脂肪酸延长酶复合物的酶，是显着较高的颖果发育早于后来。与随后的表皮脂质生物合成途径相关的基因在发育早期也表达较高，包括脱羰基和还原途径以及甾醇生物合成。角质层组成的变化表明，降低比例的烷烃和较高比例的脂肪酸与发展的良好品质的谷壳粘附，除了较高比例的甾醇。
The caryopses of barley become firmly adhered to the husk during grain development through a cuticular cementing layer on the caryopsis surface. The degree of this attachment varies among cultivars, with poor quality adhesion causing "skinning", an economically significant grain quality defect for the malting industry. Malting cultivars encompassing a range of husk adhesion qualities were grown under a misting treatment known to induce skinning. Development of the cementing layer was examined by electron microscopy and compositional changes of the cementing layer were investigated with gas-chromatography followed by mass spectroscopy. Changes in gene expression during adhesion development were examined with a custom barley microarray. The abundance of transcripts involved early in cuticular lipid biosynthesis, including those encoding acetyl-CoA carboxylase, and all four members of the fatty acid elongase complex of enzymes, was significantly higher earlier in caryopsis development than later. Genes associated with subsequent cuticular lipid biosynthetic pathways were also expressed higher early in development, including the decarbonylation and reductive pathways, and sterol biosynthesis. Changes in cuticular composition indicate that lowered proportions of alkanes and higher proportions of fatty acids are associated with development of good quality husk adhesion, in addition to higher proportions of sterols.