外源半胱氨酸调控小麦离体穗培养籽粒氨基酸、贮藏蛋白以及麦谷蛋白大聚合体
首发时间:2016-05-26
摘要:半胱氨酸属于含硫氨基酸,在麦谷蛋白大聚合体形成中起重要作用。本试验添加不同浓度半胱氨酸作为硫源和部分氮源,离体穗培养扬麦16,研究培养14天后小麦穗部籽粒、穗轴和颖壳中氮硫的分配,籽粒品质参数。结果表明外源半胱氨酸提高了小麦籽粒和非籽粒部分硫含量,适量半胱氨酸可提高蛋白质含量,显著降低氮硫比。外源半胱氨酸增加籽粒中部分氨基酸含量、贮藏蛋白含量,主要增加富硫蛋白(LMW-GS和富硫醇溶蛋白)含量。适量半胱氨酸提高麦谷蛋白大聚合体(GMP)含量及大粒径麦谷蛋白大聚合体,高浓度半胱氨酸则不利于麦谷蛋白大聚合体的形成。推测GMP形成可能与谷胱甘肽的氧还平衡和麦谷蛋白亚基供应有关,高浓度半胱氨酸条件下离体穗中GSSG/GSH增加,HMW-GS/LMW-GS降低,不利于GMP的聚合。
关键词: 小麦 外源半胱氨酸 体外培养 氨基酸组分 贮藏蛋白 麦谷蛋白大聚合体
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Exogenous cysteine modifies amino acid compositions, storage protein and large GMP particle in grain of wheat ears cultured in vitro
Abstract:Cysteine, one of sulphur-containing amino acids, plays a pivotal role in synthesis of glutenin macropolymer(GMP). With the general aim of modifying the Sulphur-rich storage protein in wheat grain, exogenous cysteine as sulphur and partial nitrogen resources was added into the growh medium of wheat ears culture in vitro, the allocation of sulphur and nitrogen resources into grain and husk plus rachis and the parameters of grain qualities were determined. Results indicated that the added cysteine enhanced the accumulation of sulphur and nitrogen in ears and grain took priority of sulphur resources over husk plus rachis. Next, the parameters of grain qualities such as amino acid compositions, S-rich storage protein(LMW-GS and S-rich gliadins) were elevated with exogenous cysteine supply. Large GMP particle was increased under moderate cysteine supply, but slightly reduced under high cysteine supply. The increase of GSSG/GSH and decrease of HMW-GS/LMW-GS may depress GMP synthesis with excess cysteine.
Keywords: Wheat Exogenous cysteine Cultured in vitro Amino acid compositions Storage protein GMP
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No.4691093802330146****
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外源半胱氨酸调控小麦离体穗培养籽粒氨基酸、贮藏蛋白以及麦谷蛋白大聚合体
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