Supikova Klara, Žukauskaitė Asta, Kosinova Andrea, Pěnčík Aleš, De Diego Nuria, Spíchal Lukáš, Fellner Martin, Skorepova Katerina, Gruz Jiri
Department of Experimental Biology, Palacký University Olomouc, Šlechtitelů 27, CZ-77900, Olomouc, Czech Republic.
Department of Chemical Biology, Palacký University Olomouc, Šlechtitelů 27, CZ-77900, Olomouc, Czech Republic.
Plant Cell Rep. 2024 Dec 20;44(1):8. doi: 10.1007/s00299-024-03399-1.
N-Sulfonated IAA was discovered as a novel auxin metabolite in Urtica where it is biosynthesized de novo utilizing inorganic sulfate. It showed no auxin activity in DR5::GUS assay, implying possible inactivation/storage mechanism. A novel auxin derivative, N-sulfoindole-3-acetic acid (IAA-N-SOH, SIAA), was discovered in stinging nettle (Urtica dioica) among 116 sulfonated metabolites putatively identified by a semi-targeted UHPLC-QqTOF-MS analysis of 23 plant/algae/fungi species. These sulfometabolites were detected based on the presence of a neutral loss of sulfur trioxide, as indicated by the m/z difference of 79.9568 Da in the MS spectra. The structure of newly discovered SIAA was confirmed by synthesizing its standard and comparing retention time, m/z and MS spectrum with those of SIAA found in Urtica. To study its natural occurrence, 73 species in total were further analyzed by UHPLC-QqTOF-MS or targeted UHPLC-MS/MS method with a limit of detection of 244 fmol/g dry weight. However, SIAA was only detected in Urtica at a concentration of 13.906 ± 9.603 nmol/g dry weight. Its concentration was > 30 times higher than that of indole-3-acetic acid (IAA), and the SIAA/IAA ratio was further increased under different light conditions, especially in continuous blue light. In addition to SIAA, structurally similar metabolites, N-sulfoindole-3-lactic acid, 4-(sulfooxy)phenyllactic acid and 4-(sulfooxy)phenylacetic acid, were detected in Urtica for the first time. SIAA was biosynthesized from inorganic sulfate in seedlings, as confirmed by the incorporation of exogenous S-ammonium sulfate (1 mM and 10 mM). SIAA exhibited no auxin activity, as demonstrated by both the Arabidopsis DR5::GUS assay and the Arabidopsis phenotype analysis. Sulfonation of IAA may therefore be a mechanism for IAA deactivation and/or storage in Urtica, similar to sulfonation of the jasmonates in Arabidopsis.
N-磺化吲哚-3-乙酸（IAA）是在荨麻中发现的一种新型生长素代谢物，它利用无机硫酸盐从头生物合成。在DR5::GUS分析中，它没有显示出生长素活性，这意味着可能存在失活/储存机制。通过对23种植物/藻类/真菌物种进行半靶向超高效液相色谱-四极杆飞行时间质谱（UHPLC-QqTOF-MS）分析，在116种推定鉴定的磺化代谢物中，在荨麻（Urtica dioica）中发现了一种新型生长素衍生物，N-磺基吲哚-3-乙酸（IAA-N-SOH，SIAA）。这些硫代谢物是根据质谱图中79.9568 Da的质荷比差异所指示的三氧化硫中性丢失的存在而检测到的。通过合成其标准品并将保留时间、质荷比和质谱与荨麻中发现的SIAA进行比较，证实了新发现的SIAA的结构。为了研究其天然存在情况，总共73个物种通过UHPLC-QqTOF-MS或靶向UHPLC-MS/MS方法进行了进一步分析，检测限为244 fmol/g干重。然而，仅在荨麻中检测到SIAA，其浓度为13.906±9.603 nmol/g干重。其浓度比吲哚-3-乙酸（IAA）高30倍以上，并且在不同光照条件下，尤其是在连续蓝光下，SIAA/IAA比值进一步增加。除了SIAA，在荨麻中首次检测到结构相似的代谢物N-磺基吲哚-3-乳酸、4-（磺氧基）苯乳酸和4-（磺氧基）苯乙酸。通过外源硫酸铵（1 mM和10 mM）的掺入证实，SIAA是在幼苗中由无机硫酸盐生物合成的。如拟南芥DR5::GUS分析和拟南芥表型分析所示，SIAA没有显示出生长素活性。因此，IAA的磺化可能是荨麻中IAA失活和/或储存的一种机制，类似于拟南芥中茉莉酸酯的磺化。
