Moonlighting Function of Phytochelatin Synthase1 in Extracellular Defense against Fungal Pathogens1[OPEN]
Moonlighting Function of Phytochelatin Synthase1 in Extracellular Defense against Fungal Pathogens1[OPEN]
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DOI：
10.1104/pp.19.01393
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发表时间：
2020-04-01
期刊：
影响因子：
7.4
通讯作者：
Somerville, Shauna
中科院分区：
文献类型：
--
作者：
Hematy, Kian;Lim, Melisa;Somerville, Shauna
植物螯合素合成酶（PCS）是植物解毒重金属的关键组分。PCS通过肽酶活性催化谷胱甘肽合成肽植物螯合素和谷胱甘肽缀合物的降解。在这里，我们描述了PCS在植物病原真菌的抗病性中的作用。pen 4突变体是与镉不敏感1（cad 1/pcs 1）突变体等位的，是从对非适应大麦真菌病原体禾本科白粉病菌抗性降低的拟南芥突变体筛选中回收的。大麦锈病菌在健康植物细胞的细胞质中发现的PCS 1在病原体攻击时移位，并与固定化线粒体表面上的PEN 2黑芥子酶共定位。pcs 1和pen 2突变体植物在病原体诱导的吲哚芥子油苷衍生化合物的积累中表现出相似的代谢缺陷，这表明pen 2和pcs 1在相同的代谢途径中起作用。PCS 1在这一途径中的功能是独立的植物螯合素的合成和谷胱甘肽结合物的脱甘氨酸，作为PCS 1的催化位点突变体仍然在吲哚芥子油苷代谢的功能。PCS 1是一种在非生物胁迫应答中发挥重要作用的兼职蛋白，在植物的细胞外免疫应答和病原菌诱导的硫代葡萄糖苷代谢过程中起着不可或缺的作用。
Phytochelatin synthase (PCS) is a key component of heavy metal detoxification in plants. PCS catalyzes both the synthesis of the peptide phytochelatin from glutathione and the degradation of glutathione conjugates via peptidase activity. Here, we describe a role for PCS in disease resistance against plant pathogenic fungi. The pen4 mutant, which is allelic to cadmium insensitive1 (cad1/pcs1) mutants, was recovered from a screen for Arabidopsis mutants with reduced resistance to the nonadapted barley fungal pathogen Blumeria graminis f. sp. hordei. PCS1, which is found in the cytoplasm of cells of healthy plants, translocates upon pathogen attack and colocalizes with the PEN2 myrosinase on the surface of immobilized mitochondria. pcs1 and pen2 mutant plants exhibit similar metabolic defects in the accumulation of pathogen-inducible indole glucosinolate-derived compounds, suggesting that PEN2 and PCS1 act in the same metabolic pathway. The function of PCS1 in this pathway is independent of phytochelatin synthesis and deglycination of glutathione conjugates, as catalytic-site mutants of PCS1 are still functional in indole glucosinolate metabolism. In uncovering a peptidase-independent function for PCS1, we reveal this enzyme to be a moonlighting protein important for plant responses to both biotic and abiotic stresses.PCS1 is a moonlighting protein that functions in abiotic stress response and is indispensable for proper extracellular immune responses and pathogen-triggered glucosinolate metabolism.