Int J Mol Sci:中科院昆明植物所刘爱忠研究组发表烟草代谢基因研
2016年8月8日，国际期刊《InteRNAtional Journal of molecular Sciences》杂志上在线发表了中国科学院昆明植物研究所刘爱忠研究组题为“β-ketoacyl-acyl Carrier Protein Synthase Ι (KASI) Plays Crucial Roles in the Plant Growth and Fatty Acids Synthesis in Tobacco”的研究论文，研究揭示了烟草β-酮脂酰-ACP合酶 I (KASI)在植物发育和脂肪酸合成中的重要作用。版纳植物园博士研究生阳天泉为论文第一作者，刘爱忠研究员为论文通讯作者。
脂肪酸(Fatty acids，FA)代谢是植物生理代谢的主要组成部分，对植物的生长发育具有重要生理意义。在植物中，FA的生物合成通常发生在细胞的质体中，负责碳连延伸的脂肪酸合酶为β-酮脂酰-ACP合酶(KAS)。目前关于KASI对植物FA合成的分子机制以及对植物生长发育的影响尚不清楚。博士研究生阳天泉，以烟草为研究材料，利用RNAi介导的基因沉默，调查了KASI在烟草FA合成和植物发育过程中的作用。
研究发现烟草基因组有两个KASI基因，分别命名为NtKASI-1和NtKASI-2。通过构建基因沉默载体转化烟草，获得RNAi转基因植株。结果显示：kasI-1 RNAi (NtKASI-1基因的沉默)转基因植株有明显的花斑叶和矮化现象，显微镜观察到叶片花斑区域叶绿体发育异常，而且kasI-1 RNAi植株叶片的脂肪酸含量明显下降;kasI-1/2 RNAi (NtKASI-2基因的沉默)转基因烟草相对于野生型没有明显差异，叶片脂肪酸含量和成分均没有显著变化;而kasI-1/2 RNAi(NtKASI-1和 NtKASI-2基因的共沉默)转基因烟草表现出比kasI-1 RNAi植株更严重的花斑叶和矮化表型，而且共沉默植株结实率降低甚至败育，植株叶片的脂肪酸成分和含量均改变。这些结果说明烟草NtKASI-1和NtKASI-2存在部分的功能冗余，且NtKASI-1发挥着主要功能。
烟草KASI基因沉默引起植物叶片花斑和叶绿体发育异常
原文链接：
β-Ketoacyl-acyl Carrier Protein Synthase I (KASI) Plays Crucial Roles in the Plant growth and Fatty Acids Synthesis in Tobacco
原文摘要：
Fatty acids serve many functions in plants, but the effects of some key genes involved in fatty acids biosynthesis on plants growth and development are not well understood yet. To understand the functions of 3-ketoacyl-acyl-carrier protein synthase I (KASI) in tobacco, we isolated two KASI homologs, which we have designated NtKASI-1 and NtKASI-2. expression analysis showed that these two KASI genes were transcribed constitutively in all tissues examined. Over-expression of NtKASI-1 in tobacco changed the fatty acid content in leaves, whereas over-expressed lines of NtKASI-2 exhibited distinct phenotypic features such as slightly variegated leaves and reduction of the fatty acid content in leaves, similar to the silencing plants of NtKASI-1 gene. Interestingly, the silencing of NtKASI-2 gene had no discernibly altered phenotypes compared to wild type. The double silencing plants of these two genes enhanced the phenotypic changes during vegetative and reproductive growth compared to wild type. These results uncovered that these two KASI genes had the partially functional redundancy, and that the KASI genes played a key role in regulating fatty acids synthesis and in mediating plant growth and development in tobacco.
作者：刘爱忠
