Bile acid: sodium symporter family protein 2 (BASS2) is a sodium-dependent pyruvate transporter, which transports pyruvate from cytosol into plastid in plants. In this study, we investigated the function of chloroplast envelope membrane-localized BnaBASS2 in seed metabolism and seed oil accumulation of Brassica napus (B. napus). Four BASS2 genes were identified in the genome of B. napus. BnaA05.BASS2 was overexpressed while BnaA05.BASS2 and BnaC04.BASS2-1 were mutated by CRISPR in B. napus. Metabolite analysis revealed that the manipulation of BnaBASS2 caused significant changes in glycolysis-, fatty acid synthesis–, and energy-related metabolites in the chloroplasts of 31 day-after-flowering (DAF) seeds. The analysis of fatty acids and lipids in developing seeds showed that BnaBASS2 could affect lipid metabolism and oil accumulation in developing seeds. Moreover, the overexpression (OE) of BnaA05.BASS2 could promote the expression level of multiple genes involved in the synthesis of oil and the formation of oil body during seed development. Disruption of BnaA05.BASS2 and BnaC04.BASS2-1 resulted in decreasing the seed oil content (SOC) by 2.8%–5.0%, while OE of BnaA05.BASS2 significantly promoted the SOC by 1.4%–3.4%. Together, our results suggest that BnaBASS2 is a potential target gene for breeding B. napus with high SOC.

中文翻译：

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丙酮酸转运蛋白 BnaBASS2 影响甘蓝型油菜种子油的积累


胆汁酸：钠同向转运蛋白家族蛋白 2 (BASS2) 是一种钠依赖性丙酮酸转运蛋白，可将丙酮酸从细胞质转运到植物中的质体中。在本研究中，我们研究了叶绿体包膜定位的 BnaBASS2 在甘蓝型油菜( B. napus ) 种子代谢和种子油积累中的功能。在甘蓝型油菜的基因组中鉴定出了四个BASS2基因。 BnaA05.BASS2过表达，而BnaA05.BASS2和BnaC04.BASS2-1在甘蓝型油菜中被 CRISPR 突变。代谢物分析表明， BnaBASS2的操作导致花后 31 天 (DAF) 种子叶绿体中糖酵解、脂肪酸合成和能量相关代谢物的显着变化。对发育中种子中脂肪酸和脂质的分析表明， BnaBASS2可以影响发育中种子中的脂质代谢和油脂积累。此外， BnaA05.BASS2的过表达（OE）可以促进种子发育过程中参与油合成和油体形成的多个基因的表达水平。 BnaA05.BASS2和BnaC04.BASS2-1的破坏导致种子油含量 (SOC) 降低 2.8%–5.0%，而BnaA05.BASS2的 OE 显着提高 SOC 1.4%–3.4%。总之，我们的结果表明BnaBASS2是培育高 SOC甘蓝型油菜的潜在靶基因。