南湖新闻网讯（通讯员 夏慧）7月12日，我校油菜团队在Cell Reports发表题为“Brassica napus BnaNTT1 modulates ATP homeostasis in plastids to sustain metabolism and growth”的研究论文。该研究阐明了转运蛋白BnaNTT1在调控油菜代谢和生长中的功能和分子机制。
植物细胞内质体与细胞质之间交换ATP/ADP的转运蛋白为核苷酸三磷酸转运蛋白（nucleotide triphosphate transporter, NTT），它负责从胞质中转运ATP进入质体，交换等量的ADP，维持质体内ATP/ADP的动态平衡，满足质体内脂肪酸和氨基酸合成等ATP依赖的代谢活动。植物中NTT是否结合并转运胞质ATP进入质体的研究鲜有报道，NTT调控植物生长和代谢的分子机制也尚不清楚。
BnaNTT1转运ATP并影响油菜代谢的功能和机制
该研究首先证实了BnaNTT1蛋白定位于叶绿体内膜上，通过在体外表达蛋白，利用NanoDSF、SPR技术以及分离油菜叶片质体进行代谢物的检测，证明BnaNTT1可以结合ATP，将胞质ATP转运到质体中，并将ADP交换到细胞质中。
研究结果表明，突变BnaNTT1降低了胞质中的糖酵解效率，同时降低了叶绿体中DGDG、MGDG和PG等脂类代谢物的含量，导致类囊体结构缺陷，降低了光合效率并导致油菜生长缓慢，种子中含油量也显著下降。超量表达BnaNTT1引起质体内ATP含量升高，胞质中ADP含量升高，胞质中ADP/ATP比值上升促进了糖酵解效率。质体中升高的ATP水平可能提高了AGPase的活性，促进了淀粉的生成。种子质体中升高的ATP提高了脂肪酸的合成速率，进而促进了种子中油脂积累。该研究揭示了油菜转运蛋白BnaNTT1通过将胞质ATP转运到质体以维持油菜代谢和生长并促进脂质合成的生化与分子机制，为油菜高产高油育种提供了靶基因。
我校作物遗传改良国家重点实验室洪越博士、硕士研究生夏慧和李晓为论文的共同第一作者，郭亮教授为论文通讯作者。该研究得到了国家自然科学基金和湖北洪山实验室重大项目资助。
审核人：郭亮
【英文摘要】
The plastid-localized nucleotide triphosphate transporter (NTT) transports cytosolic adenosine triphosphate (ATP) into plastid to satisfy the needs of biochemistry activities in plastid. Here, we investigate the key functions of two conserved BnaNTT1 genes, BnaC06.NTT1b and BnaA07.NTT1a, in Brassica napus. Binding assays and metabolic analysis indicate that BnaNTT1 binds ATP/adenosine diphosphate (ADP), transports cytosolic ATP into chloroplast, and exchanges ADP into cytoplasm. Thylakoid structures are abnormal and plant growth is retarded in CRISPR mutants of BnaC06.NTT1b and BnaA07.NTT1a. Both BnaC06.NTT1b and BnaA07.NTT1a play important roles in the regulation of ATP/ADP homeostasis in plastid. Manipulation of BnaC06.NTT1b and BnaA07.NTT1a causes significant changes in glycolysis and membrane lipid composition, suggesting that increased ATP in plastid fuels more seed-oil accumulation. Together, this study implicates the vital role of BnaC06.NTT1b and BnaA07.NTT1a in plant metabolism and growth in B. napus.
论文链接：https://www.cell.com/cell-reports/fulltext/S2211-1247(22)00858-0
