In phosphate (Pi)‐deprived Arabidopsis (Arabidopsis thaliana ), phosphatidylglycerol (PG) is substituted by sulfolipid for maintaining Pi homeostasis. Sulfoquinovosyl diacylglycerol1 (AtSQD1 ) encodes a protein, which catalyzes uridine diphosphate glucose (UDPG) and sulfite (SO₃²⁻) to UDP‐sulfoquinovose, which is a key component in the sulfolipid biosynthetic pathway. In this study, a reverse genetics approach was employed to decipher the function of the AtSQD1 homolog OsSQD1 in rice. Differential expressions of OsSQD1 in different tissue and response to −P and −S also detected, respectively. The in vitro protein assay and analysis suggests that OsSQD1 is a UDP‐sulfoquinovose synthase. Transient expression analysis showed that OsSQD1 is located in the chloroplast. The analyses of the knockout (ossqd1 ) and knockdown (Ri1 and Ri2) mutants demonstrated reductions in Pi and total P concentrations, ³²Pi uptake rate, expression levels of Pi transporters and altered developmental responses of root traits, which were accentuated during Pi deficiency. The inhibitory effects of the OsSQD1 mutation were also evident in the development of reproductive tissue. Furthermore, OsSQD1 differently affects lipid composition under different Pi regime affects sulfur (S) homeostasis. Together, the study revealed that OsSQD1 affects Pi and S homeostasis, and lipid composition in response to Pi deprivation.

中文翻译：

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OsSQD1处于磷和硫代谢的十字路口，响应磷的剥夺影响植物的形态和脂质组成。

在磷酸盐（Pi）剥夺的拟南芥（Arabidopsis thaliana）中，磷脂酰甘油（PG）被硫脂替代以维持Pi稳态。磺基喹喔酰基二酰基甘油1（AtSQD1）编码一种蛋白质，该酶将尿苷二磷酸葡萄糖（UDPG）和亚硫酸盐（SO ₃ ^2-）催化为UDP-磺基奎诺糖，这是糖脂生物合成途径中的关键成分。在这项研究中，采用反向遗传学方法破译了水稻中AtSQD1同系物OsSQD1的功能。还分别检测到OsSQD1在不同组织中的差异表达以及对-P和-S的响应。体外蛋白测定和分析表明OsSQD1是UDP-磺基古诺糖合成酶。瞬时表达分析表明，OsSQD1位于叶绿体中。对敲除（ossqd1）和敲除（Ri1和Ri2）突变体的分析表明，Pi和总P浓度降低，³² Pi吸收率，Pi转运蛋白表达水平降低和根系性状的发育响应发生改变，这在Pi缺乏时加剧。OsSQD1突变的抑制作用在生殖组织的发育中也很明显。此外，OsSQD1在不同的Pi方案影响硫（S）稳态时，对脂质组成的影响也不同。研究表明，OsSQD1 影响Pi和S的稳态，以及对Pi剥夺做出反应的脂质组成。