On-tissue chemical derivatization(OTCD)effectively enhances ionization efficiency of low abundant and poorly ionized functional molecules to improve detection sensitivity and coverage of mass spectrometry imaging(MSI)...On-tissue chemical derivatization(OTCD)effectively enhances ionization efficiency of low abundant and poorly ionized functional molecules to improve detection sensitivity and coverage of mass spectrometry imaging(MSI).Combination OTCD and MSI provides a novel strategy for visualizing previously undisclosed metabolic heterogeneity in tumor.Herein,we present a method to visualize heterogeneous metabolism of oxylipins within tumor by coupling OTCD with airflow-assisted desorption electrospray ionization(AFADESI)-MSI.Taking Girard’s P as a derivatization reagent,easily ionized hydrazide and quaternary amine groups were introduced into the structure of carbonyl metabolites via condensation reaction.Oxylipins,including 127 fatty aldehydes(FALs)and 71 oxo fatty acids(FAs),were detected and imaged in esophageal cancer xenograft with AFADESI-MSI after OTCD.Then t-distributed stochastic neighbor embedding and random forest were exploited to precisely locate the distribution of oxylipins in heterogeneous tumor tissue.With this method,we surprisingly found almost all FALs and oxo FAs significantly accumulated in the core region of tumor,and exhibited a gradual increase trend in tumor over time.These results reveal spatiotemporal heterogeneity of oxylipins in tumor progression,highlighting the value of OTCD combined with MSI to gain deeper insights into understanding tumor metabolism.展开更多
Plant 9-1ipoxygenases （9-LOX） and α-dioxygenases （α-DOX） initiate the synthesis of oxylipins after bacterial infection. Here, the role of these enzymes in plants＇ defense was investigated using individual Arabi...Plant 9-1ipoxygenases （9-LOX） and α-dioxygenases （α-DOX） initiate the synthesis of oxylipins after bacterial infection. Here, the role of these enzymes in plants＇ defense was investigated using individual Arabidopsis thaliana Ioxl and doxl mutants and a double Ioxl doxl mutant. Studies with Pseudomonas syringae pv. tomato （Pst） revealed the enhanced susceptibility of Ioxl to the virulent strain Pst DC3000 and the partial impairment of Ioxl and doxl mutants to activate systemic acquired resistance. Notably, both defects were enhanced in the Ioxl doxl plants as compared with individual mutants. We found that pre-treatment with 9-LOX- and α-DOX-generated oxylipins protected plant tissues against bacterial infection. The strongest effect in this respect was exerted by 9-ketooctadecatrienoic acid （9-KOT）, which is produced from linolenic acid by 9-LOX. Quantification of 9-KOT revealed its accumulation after bacterial infection. The levels were reduced in Ioxl and Ioxl doxl plants but strongly increased in the doxl mutant due to metabolic interaction of the two pathways. Transcriptional analyses indicated that 9-KOT pre-treatment modifies hormone homeostasis during bacterial infection. The nature of the changes detected suggested that 9-KOT interferes with the hormonal changes caused by bacterial effectors. This notion was substantiated by the finding that 9-KOT failed to reduce the growth of PstDC3OOOhrpA, a mutant compromised in effector secretion, and of the avirulent strain Pst DC3000 avrRpml. Further support for the action of the 9-LOX- and α-DOX-oxylipin pathways as modulators of hormone homeostasis was the ob- servation that Ioxl doxl seedlings are hypersensitive to the growth-inhibitory effect of ABA and showed enhanced ac- tivation of ABA-inducible marker genes as compared with wild-type plants.展开更多
Plants have evolved complex signaling pathways to coordinate responses to developmental and environmental Information. The oxylipin pathway Is one pivotal lipid-based signaling network, composed of several competing b...Plants have evolved complex signaling pathways to coordinate responses to developmental and environmental Information. The oxylipin pathway Is one pivotal lipid-based signaling network, composed of several competing branch pathways, that determines the plant＇s ability to adapt to various stimuli. Activation of the oxyllpln pathway Induces the de novo synthesis of biologically active metabolltes called ＂oxyllplns＂. The relative levels of these metabolltes are a distinct indicator of each plant species and determine the ability of plants to adapt to different stimuli. The two major branches of the oxyllpln pathway, allene oxide synthase （AOS） and hydroperoxlde lyase （HPL） are responsible for production of the signaling compounds, jasmonates and aldehydes respectively. Here, we compare and contrast the regulation of AOS and HPL branch pathways In rice and Arabidopsis as model monocotyledonous and dicotyledonous systems. These analyses provide new Insights Into the evolution of JAs and aldehydes signaling pathways, and the complex network of processes responsible for stress adaptations In monocots and dicots.展开更多
The jasmonic acid （JA） pathway is the main signal-transduction pathway induced by insect folivory. Mutant plants affected in the jasmonate pathway （18：0 and/or 16：0-oxylipin routes） were studied to assess the ef...The jasmonic acid （JA） pathway is the main signal-transduction pathway induced by insect folivory. Mutant plants affected in the jasmonate pathway （18：0 and/or 16：0-oxylipin routes） were studied to assess the effects of JA and its oxylipin intermediates 12-oxophytodienoic acid （OPDA） and dinor-OPDA （dnOPDA） on interconnected signal- transduction pathways that underlie induced defenses in Arabidopsis. Our data show that the oxylipin jasmonates dnOPDA, OPDA and JA have different roles in defense signaling induced after feeding by the chewing-biting caterpillar Pieris rapae. Jasmonic acid, and not OPDA or dnOPDA, is the major signaling compound required for the induction of the defense-related genes LOX2 （Lipo：~vgenase 2）, OPR3 （12-Oxophytodienoate reductase 3）, ACX1 （Acyl-CoA oxidase 1） and PAL1 （Phenvlalanine ammonia-lyase 1）. Monitoring PAL1 transcript levels clearly showed that accumulation of JA upon P rapae feeding results in the induction of the salicylic acid pathway. Furthermore, JA is the major signaling compound required for the P rapae-induced expression of the defense-related gene HPL1 （Hydroperoxide lyase 1）. The jasmonate dnOPDA influences the induction of the HPk- branch as well, yet its effect is antagonistic to the effect of JA. Our data show that these jasmonates may be used to fine-tune Arabidopsis＇ herbivore-induced responses in terms of the HPL-branch from the oxylipin pathway.展开更多
基金supported by the National Natural Science Foundation of China(No.21927808)the Chinese Academy of Medical Science(CAMS)Innovation Fund for Medical Sciences(CIFMS,Nos.2022-I2M-2-002 and 2021-1-I2M-028).
文摘On-tissue chemical derivatization(OTCD)effectively enhances ionization efficiency of low abundant and poorly ionized functional molecules to improve detection sensitivity and coverage of mass spectrometry imaging(MSI).Combination OTCD and MSI provides a novel strategy for visualizing previously undisclosed metabolic heterogeneity in tumor.Herein,we present a method to visualize heterogeneous metabolism of oxylipins within tumor by coupling OTCD with airflow-assisted desorption electrospray ionization(AFADESI)-MSI.Taking Girard’s P as a derivatization reagent,easily ionized hydrazide and quaternary amine groups were introduced into the structure of carbonyl metabolites via condensation reaction.Oxylipins,including 127 fatty aldehydes(FALs)and 71 oxo fatty acids(FAs),were detected and imaged in esophageal cancer xenograft with AFADESI-MSI after OTCD.Then t-distributed stochastic neighbor embedding and random forest were exploited to precisely locate the distribution of oxylipins in heterogeneous tumor tissue.With this method,we surprisingly found almost all FALs and oxo FAs significantly accumulated in the core region of tumor,and exhibited a gradual increase trend in tumor over time.These results reveal spatiotemporal heterogeneity of oxylipins in tumor progression,highlighting the value of OTCD combined with MSI to gain deeper insights into understanding tumor metabolism.
文摘Plant 9-1ipoxygenases （9-LOX） and α-dioxygenases （α-DOX） initiate the synthesis of oxylipins after bacterial infection. Here, the role of these enzymes in plants＇ defense was investigated using individual Arabidopsis thaliana Ioxl and doxl mutants and a double Ioxl doxl mutant. Studies with Pseudomonas syringae pv. tomato （Pst） revealed the enhanced susceptibility of Ioxl to the virulent strain Pst DC3000 and the partial impairment of Ioxl and doxl mutants to activate systemic acquired resistance. Notably, both defects were enhanced in the Ioxl doxl plants as compared with individual mutants. We found that pre-treatment with 9-LOX- and α-DOX-generated oxylipins protected plant tissues against bacterial infection. The strongest effect in this respect was exerted by 9-ketooctadecatrienoic acid （9-KOT）, which is produced from linolenic acid by 9-LOX. Quantification of 9-KOT revealed its accumulation after bacterial infection. The levels were reduced in Ioxl and Ioxl doxl plants but strongly increased in the doxl mutant due to metabolic interaction of the two pathways. Transcriptional analyses indicated that 9-KOT pre-treatment modifies hormone homeostasis during bacterial infection. The nature of the changes detected suggested that 9-KOT interferes with the hormonal changes caused by bacterial effectors. This notion was substantiated by the finding that 9-KOT failed to reduce the growth of PstDC3OOOhrpA, a mutant compromised in effector secretion, and of the avirulent strain Pst DC3000 avrRpml. Further support for the action of the 9-LOX- and α-DOX-oxylipin pathways as modulators of hormone homeostasis was the ob- servation that Ioxl doxl seedlings are hypersensitive to the growth-inhibitory effect of ABA and showed enhanced ac- tivation of ABA-inducible marker genes as compared with wild-type plants.
基金Supported by UC discovery and NSF grants to KD. Publication of this paper is supported by the National Natural Science Foundation of China （30624808） and Science Publication Foundation of the Chinese Academy of Sciences.Acknowledgements The authors would like to acknowledge G. Raman for performing the jasmonate and aldehyde measurements.
文摘Plants have evolved complex signaling pathways to coordinate responses to developmental and environmental Information. The oxylipin pathway Is one pivotal lipid-based signaling network, composed of several competing branch pathways, that determines the plant＇s ability to adapt to various stimuli. Activation of the oxyllpln pathway Induces the de novo synthesis of biologically active metabolltes called ＂oxyllplns＂. The relative levels of these metabolltes are a distinct indicator of each plant species and determine the ability of plants to adapt to different stimuli. The two major branches of the oxyllpln pathway, allene oxide synthase （AOS） and hydroperoxlde lyase （HPL） are responsible for production of the signaling compounds, jasmonates and aldehydes respectively. Here, we compare and contrast the regulation of AOS and HPL branch pathways In rice and Arabidopsis as model monocotyledonous and dicotyledonous systems. These analyses provide new Insights Into the evolution of JAs and aldehydes signaling pathways, and the complex network of processes responsible for stress adaptations In monocots and dicots.
文摘The jasmonic acid （JA） pathway is the main signal-transduction pathway induced by insect folivory. Mutant plants affected in the jasmonate pathway （18：0 and/or 16：0-oxylipin routes） were studied to assess the effects of JA and its oxylipin intermediates 12-oxophytodienoic acid （OPDA） and dinor-OPDA （dnOPDA） on interconnected signal- transduction pathways that underlie induced defenses in Arabidopsis. Our data show that the oxylipin jasmonates dnOPDA, OPDA and JA have different roles in defense signaling induced after feeding by the chewing-biting caterpillar Pieris rapae. Jasmonic acid, and not OPDA or dnOPDA, is the major signaling compound required for the induction of the defense-related genes LOX2 （Lipo：~vgenase 2）, OPR3 （12-Oxophytodienoate reductase 3）, ACX1 （Acyl-CoA oxidase 1） and PAL1 （Phenvlalanine ammonia-lyase 1）. Monitoring PAL1 transcript levels clearly showed that accumulation of JA upon P rapae feeding results in the induction of the salicylic acid pathway. Furthermore, JA is the major signaling compound required for the P rapae-induced expression of the defense-related gene HPL1 （Hydroperoxide lyase 1）. The jasmonate dnOPDA influences the induction of the HPk- branch as well, yet its effect is antagonistic to the effect of JA. Our data show that these jasmonates may be used to fine-tune Arabidopsis＇ herbivore-induced responses in terms of the HPL-branch from the oxylipin pathway.
