磷脂酰肌醇特异性磷脂酶C(PI-PLC)的快速活化发生在植物的生物和非生物胁迫刺激后的早期,与钙通道诱导的钙(Ca2)内流直接相关。外源氯化钙(CaCl2)介导钙信号转导,促进切碎胡萝卜中γ-氨基丁酸的积累和营养品质,但其产生机制仍不确定。因此,本研究调查了PI-PLC相关磷脂代谢的参与.我们的结果表明,CaCl2处理可促进PI-PLC的表达和活性,并增加切碎的胡萝卜中肌醇1,4,5-三磷酸和六磷酸的含量。多谷氨酸受体样通道(DcGLR)的转录本,谷氨酸和γ-氨基丁酸(GABA)含量,在储存过程中,切碎的胡萝卜中的CaCl2处理会诱导Ca2流入。然而,PI-PLC抑制剂(U73122)处理抑制了PI-PLC的激活,许多DcGLR家族基因表达水平的增加,和Ca2+流入。此外,DcPI-PLC4/6和DcGLR蛋白的鉴定,随着对PLCXc等特征域的分析,PLCYc,C2域,跨膜区,和配体结合域,表明它们参与磷脂催化和胡萝卜中的钙转运。此外,烟草叶片中DcPI-PLC4/6的过表达通过激活NtGLR的表达以及谷氨酸和GABA的积累来诱导Ca2流入。这些发现共同表明,CaCl2处理诱导的PI-PLC激活影响DcGLR表达水平介导细胞溶质Ca2+流入,因此,强调切碎的胡萝卜中钙信号产生和GABA生物合成中的“PI-PLC-GLR-Ca2+”途径。
The rapid activation of phosphatidylinositol-specific phospholipase C (PI-PLC) occurs early after the stimulation of biotic and abiotic stress in plants, which directly associated with the calcium channel-induced calcium ion (Ca2+) influx. Exogenous calcium chloride (CaCl2) mediates the calcium signaling transduction to promote the γ-aminobutyric acid accumulation and nutritional quality in shredded carrots whereas the generation mechanism remains uncertain. Therefore, the involvement of PI-PLC-associated phospholipid metabolism was investigated in present study. Our result revealed that CaCl2 treatment promoted the expression and activity of PI-PLC and increased the inositol 1,4,5-trisphosphate and hexakisphosphate content in shredded carrots. The transcripts of multi-glutamate receptor-like channels (DcGLRs), the glutamate and γ-aminobutyric acid (GABA) content, and Ca2+ influx were induced by CaCl2 treatment in shredded carrots during storage. However, PI-PLC inhibitor (U73122) treatment inhibited the activation of PI-PLC, the increase of many DcGLRs family genes expression levels, and Ca2+ influx. Moreover, the identification of DcPI-PLC4/6 and DcGLRs proteins, along with the analysis of characteristic domains such as PLCXc, PLCYc, C2 domain, transmembranous regions, and ligand binding domain, suggests their involvement in phospholipid catalysis and calcium transport in carrots. Furthermore, DcPI-PLC4/6 overexpression in tobacco leaves induced the Ca2+ influx by activating the expressions of NtGLRs and the accumulation of glutamate and GABA. These findings collectively indicate that CaCl2 treatment-induced PI-PLC activation influences DcGLRs expression levels to mediate cytosolic Ca2+ influx, thus, highlighting the \"PI-PLC-GLRs-Ca2+\" pathway in calcium signaling generation and GABA biosynthesis in shredded carrots.