| 摘要: |
| 【目的】磷酸烯醇式丙酮酸羧化酶（phosphoenolpyruvate carboxylase，PEPC）参与植物碳代谢，并且在碳氮耦合代谢调节过程中扮演着重要角色。分析导入外源C4-PEPC对水稻稻谷粒形和稻米品质及成分变化的影响，进一步阐明C4-PEPC在C3植物水稻中的作用。【方法】以航2号（对照）和转C4-PEPC水稻为材料，采用万深SC-G型自动考种及千粒重分析仪分析稻谷的粒形，采用电镜扫描观察稻米内部淀粉粒结构，参照标准米质测定方法测定稻米品质(直链淀粉含量、胶稠度、碱消值)；同时，测定稻米中支链淀粉、蔗糖、可溶性总糖及碳氮的含量，并采用高效液相色谱法测定稻米中的氨基酸含量。【结果】粒形分析表明，与对照航2号相比，转C4-PEPC水稻的谷粒明显较短较窄，其长、宽、周长及千粒质量也明显较小。电镜扫描显示，航2号淀粉粒排列紧密，而转C4-PEPC稻米淀粉粒排列明显比较松散。转C4-PEPC株系稻米中直链淀粉含量明显较低，而支链淀粉含量明显较高，胶稠度和碱消值与对照无明显差别，垩白率和垩白度降低，蔗糖和可溶性糖含量极显著降低。转C4-PEPC稻米的总氮含量明显较低，其中天冬氨酸、谷氨酸、丝氨酸、甘氨酸、组氨酸、精氨酸、苏氨酸、丙氨酸、酪氨酸、缬氨酸、胱氨酸、亮氨酸、苯丙氨酸、赖氨酸等14种氨基酸含量明显较低，而其余3种氨基酸，即脯氨酸、异亮氨酸、色氨酸含量与对照无明显差别。【结论】导入外源C4-PEPC后，水稻谷粒变小，淀粉粒排列松散，稻米中直链淀粉、蔗糖、可溶性糖、总氮及大部分氨基酸含量降低，而支链淀粉含量升高。 |
| 关键词: 水稻；外源C4-PEPC 水稻粒形；稻米品质 |
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| 基金项目:国家转基因生物新品种培育重大专项（2016ZX08001-004）；杂交水稻国家重点实验室（湖南杂交水稻研究中心）开放课题（2019KF10）；福建省农业科学院农业科技专项（GJPY2019005） |
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| Effect of exogenous C4-PEPC on grain shape,quality and composition of rice (Oryza sativa) |
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LIAN Ling,WU Chunzhu,HE Wei,et al
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| Abstract: |
| 【Objective】Phosphoenolpyruvate carboxylase (PEPC) involves in carbon metabolism of plants and has an important role in carbon and nitrogen interactions.This study investigated the changes in grain shape and composition of rice with exogenous C4-PEPC to clarify the effects of exogenous C4-PEPC and the role of C4-PEPC in C3 plant rice.【Method】The grain shape of Hang 2 (CK) and rice with C4-PEPC was analyzed using SC-G Rice Automatic Test Analyzer (Wanshen).The starch grain structure was observed by scanning electron microscope (SEM).Rice quality indexes including amylose content,gel consistency and alkali spreading value were determined according to the standard method of rice quality determination.The grain amylopectin,sucrose,soluble sugar,carbon and nitrogen contents were determined,and amino acid content was determined using high performance liquid chromatography (HPLC).【Result】The grain of rice with C4-PEPC was shorter and narrower compared with CK,and grain length,width,perimeter and 1 000-grain weight of rice with C4-PEPC were reduced.The starch granule of CK was arranged densely,while that of rice with C4-PEPC was arranged loosely.In contrast with CK,rice with C4-PEPC had lower grain amylose content,sucrose content,soluble sugar content,chalkiness rate and chalkiness degree,but higher amylopectin content.The gel consistency and alkali spreading value had no difference between CK and rice with C4-PEPC.The contents of grain nitrogen and 14 amino acids including Asp,Glu,Ser,Gly,His，Arg,Thr,Ala,Tyr,Val,Cys,Leu,Phe and Lys decreased,while contents of Pro,Ile and Trp unchanged in rice with C4-PEPC.【Conclusion】Introduction of exogenous C4-PEPC caused smaller grain,loose starch granule,lower contents of grain amylose,sucrose,soluble sugar,nitrogen and most of amino acids,and higher amylopectin content. |
| Key words: rice exogenous C4-PEPC rice grain shape grain quality |
