Growth promotion by endosymbiont Piriformospora indica has been observed in various plants; however, specific functional metabolites involved in P. indica mediated growth promotion are unknown. A GC-MS based untargeted metabolite analysis was used to identify Solanum lycopersicum metabolites altered during P. indica mediated growth promotion. Metabolomic analysis showed primary metabolites altered and specifically putrescine to be maximally induced in roots during the interaction. P. indica induced putrescine biosynthetic gene SlADC1 in S. lycopersicum and acts via arginine decarboxylase (ADC) mediated pathway. P. indica did not promote growth in Sladc-VIGS (virus induced gene silencing of SlADC gene) lines of S. lycopersicum and when the ADC enzyme was inhibited with an inhibitor, DL-α-(Difluoromethyl) arginine. In Arabidopsis adc knock-out mutants, P. indica do not promote growth and this response was rescued upon exogenous application of putrescine. Putrescine promoted growth by elevation of auxin (indole-3-acetic acid) and gibberellin (GA4, GA7) levels in S. lycopersicum. Putrescine is also important for P. indica hyphal growth indicating that it is co-adapted by both host and microbe. Hence, we conclude that putrescine is an essential metabolite and its biosynthesis in plants is crucial for P. indica mediated growth promotion and fungal growth.

中文翻译：

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印度Piriformospora雇用宿主腐胺促进植物生长

已经在各种植物中观察到了内共生的印度梨形孢子虫促进生长。然而，尚不知道参与P稻介导的生长促进的特定功能代谢产物。基于GC-MS的非目标代谢物分析被用于鉴定印度P介导的生长促进过程中改变的番茄。代谢组学分析表明，在相互作用过程中，根部最大程度地诱导了主要代谢产物发生改变，尤其是腐胺。印第安假单胞菌诱导番茄中的腐胺生物合成基因SlADC1，并通过精氨酸脱羧酶（ADC）介导的途径起作用。南美白对虾不促进番茄链球菌的Sladc-VIGS（病毒诱导的SlADC基因的基因沉默）系的生长，并且当ADC酶被抑制剂DL-α-（二氟甲基）精氨酸抑制时。在拟南芥adc基因敲除突变体中，印度P假单胞菌不促进生长，并且该反应在外源施用腐胺后得以挽救。腐胺通过提高番茄中的生长素（吲哚-3-乙酸）和赤霉素（GA4，GA7）水平来促进生长。腐胺对于in假单胞菌菌丝的生长也很重要，表明它与宿主和微生物共同适应。因此，我们得出结论，腐胺是必不可少的代谢产物，其在植物中的生物合成对于P稻介导的生长促进和真菌生长至关重要。hy菌丝生长表明它与宿主和微生物共同适应。因此，我们得出结论，腐胺是必不可少的代谢产物，其在植物中的生物合成对于P稻介导的生长促进和真菌生长至关重要。hy菌丝生长表明它与宿主和微生物共同适应。因此，我们得出结论，腐胺是必不可少的代谢产物，其在植物中的生物合成对于P稻介导的生长促进和真菌生长至关重要。