Biosynthesis of Phenylamide Phytoalexins in Pathogen-Infected Barley
Phytoalexins are inducible antimicrobial metabolites in plants, and have been indicated to be important for the rejection of microbial infection. HPLC analysis detected the induced accumulation of three compounds <b>1</b>−<b>3</b> in barley (<i>Hordeum vulgare...
Main Authors: | , , , , , |
---|---|
Format: | Article |
Language: | English |
Published: |
MDPI AG
2019-11-01
|
Series: | International Journal of Molecular Sciences |
Subjects: | |
Online Access: | https://www.mdpi.com/1422-0067/20/22/5541 |
id |
doaj-26c69a020f1d4d4cb02eb4c57dac597e |
---|---|
record_format |
Article |
spelling |
doaj-26c69a020f1d4d4cb02eb4c57dac597e2020-11-25T01:33:52ZengMDPI AGInternational Journal of Molecular Sciences1422-00672019-11-012022554110.3390/ijms20225541ijms20225541Biosynthesis of Phenylamide Phytoalexins in Pathogen-Infected BarleyNaoki Ube0Yukinori Yabuta1Takuji Tohnooka2Kotomi Ueno3Shin Taketa4Atsushi Ishihara5United Graduate School of Agriculture, Tottori University, Tottori 680-8553, JapanFaculty of Agriculture, Tottori University, Tottori 680-8553, JapanNational Agriculture and Food Research Organization, Tsukuba 305-8518, JapanFaculty of Agriculture, Tottori University, Tottori 680-8553, JapanInstitute of Plant Science and Resources, Okayama University, Kurashiki 710-0046, JapanFaculty of Agriculture, Tottori University, Tottori 680-8553, JapanPhytoalexins are inducible antimicrobial metabolites in plants, and have been indicated to be important for the rejection of microbial infection. HPLC analysis detected the induced accumulation of three compounds <b>1</b>−<b>3</b> in barley (<i>Hordeum vulgare</i>) roots infected by <i>Fusarium culmorum</i>, the causal agent of Fusarium root rot. Compounds <b>1</b>−<b>3</b> were identified as cinnamic acid amides of 9-hydroxy-8-oxotryptamine, 8-oxotryptamine, and (1<i>H</i>-indol-3-yl)methylamine, respectively, by spectroscopic analysis. Compounds <b>1</b> and <b>2</b> had been previously reported from wheat, whereas <b>3</b> was an undescribed compound. We named <b>1</b>−<b>3</b> as triticamides A−C, respectively, because they were isolated from barley and wheat, which belong to the Triticeae tribe. These compounds showed antimicrobial activities, indicating that triticamides function as phytoalexins in barley. The administration of deuterium-labeled <i>N</i>-cinnamoyl tryptamine (CinTry) to barley roots resulted in the effective incorporation of CinTry into <b>1</b> and <b>2</b>, which suggested that they were synthesized through the oxidation of CinTry. Nine putative tryptamine hydroxycinnamoyl transferase (THT)-encoding genes (<i>HvTHT1</i>−<i>HvTHT9</i>) were identified by database search on the basis of homology to known THT gene sequences from rice. Since <i>HvTHT7</i> and <i>HvTHT8</i> had the same sequences except one base, we measured their expression levels in total by RT-qPCR. <i>HvTHT7</i>/<i>8</i> were markedly upregulated in response to infection by <i>F. culmorum</i>. The HvTHT7 and HvTHT8 enzymes preferred cinnamoyl- and feruloyl-CoAs as acyl donors and tryptamine as an acyl acceptor, and (1<i>H</i>-indol-3-yl)methylamine was also accepted as an acyl acceptor. These findings suggested that HvTHT7/8 are responsible for the induced accumulation of triticamides in barley.https://www.mdpi.com/1422-0067/20/22/5541<i>hordeum vulgare</i>phytoalexinphenylamidetriticamidetryptamine <i>n</i>-hydroxycinnamoyl transferase<i>bipolaris sorokiniana</i><i>fusarium culmorum</i><i>fusarium graminearum</i> |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Naoki Ube Yukinori Yabuta Takuji Tohnooka Kotomi Ueno Shin Taketa Atsushi Ishihara |
spellingShingle |
Naoki Ube Yukinori Yabuta Takuji Tohnooka Kotomi Ueno Shin Taketa Atsushi Ishihara Biosynthesis of Phenylamide Phytoalexins in Pathogen-Infected Barley International Journal of Molecular Sciences <i>hordeum vulgare</i> phytoalexin phenylamide triticamide tryptamine <i>n</i>-hydroxycinnamoyl transferase <i>bipolaris sorokiniana</i> <i>fusarium culmorum</i> <i>fusarium graminearum</i> |
author_facet |
Naoki Ube Yukinori Yabuta Takuji Tohnooka Kotomi Ueno Shin Taketa Atsushi Ishihara |
author_sort |
Naoki Ube |
title |
Biosynthesis of Phenylamide Phytoalexins in Pathogen-Infected Barley |
title_short |
Biosynthesis of Phenylamide Phytoalexins in Pathogen-Infected Barley |
title_full |
Biosynthesis of Phenylamide Phytoalexins in Pathogen-Infected Barley |
title_fullStr |
Biosynthesis of Phenylamide Phytoalexins in Pathogen-Infected Barley |
title_full_unstemmed |
Biosynthesis of Phenylamide Phytoalexins in Pathogen-Infected Barley |
title_sort |
biosynthesis of phenylamide phytoalexins in pathogen-infected barley |
publisher |
MDPI AG |
series |
International Journal of Molecular Sciences |
issn |
1422-0067 |
publishDate |
2019-11-01 |
description |
Phytoalexins are inducible antimicrobial metabolites in plants, and have been indicated to be important for the rejection of microbial infection. HPLC analysis detected the induced accumulation of three compounds <b>1</b>−<b>3</b> in barley (<i>Hordeum vulgare</i>) roots infected by <i>Fusarium culmorum</i>, the causal agent of Fusarium root rot. Compounds <b>1</b>−<b>3</b> were identified as cinnamic acid amides of 9-hydroxy-8-oxotryptamine, 8-oxotryptamine, and (1<i>H</i>-indol-3-yl)methylamine, respectively, by spectroscopic analysis. Compounds <b>1</b> and <b>2</b> had been previously reported from wheat, whereas <b>3</b> was an undescribed compound. We named <b>1</b>−<b>3</b> as triticamides A−C, respectively, because they were isolated from barley and wheat, which belong to the Triticeae tribe. These compounds showed antimicrobial activities, indicating that triticamides function as phytoalexins in barley. The administration of deuterium-labeled <i>N</i>-cinnamoyl tryptamine (CinTry) to barley roots resulted in the effective incorporation of CinTry into <b>1</b> and <b>2</b>, which suggested that they were synthesized through the oxidation of CinTry. Nine putative tryptamine hydroxycinnamoyl transferase (THT)-encoding genes (<i>HvTHT1</i>−<i>HvTHT9</i>) were identified by database search on the basis of homology to known THT gene sequences from rice. Since <i>HvTHT7</i> and <i>HvTHT8</i> had the same sequences except one base, we measured their expression levels in total by RT-qPCR. <i>HvTHT7</i>/<i>8</i> were markedly upregulated in response to infection by <i>F. culmorum</i>. The HvTHT7 and HvTHT8 enzymes preferred cinnamoyl- and feruloyl-CoAs as acyl donors and tryptamine as an acyl acceptor, and (1<i>H</i>-indol-3-yl)methylamine was also accepted as an acyl acceptor. These findings suggested that HvTHT7/8 are responsible for the induced accumulation of triticamides in barley. |
topic |
<i>hordeum vulgare</i> phytoalexin phenylamide triticamide tryptamine <i>n</i>-hydroxycinnamoyl transferase <i>bipolaris sorokiniana</i> <i>fusarium culmorum</i> <i>fusarium graminearum</i> |
url |
https://www.mdpi.com/1422-0067/20/22/5541 |
work_keys_str_mv |
AT naokiube biosynthesisofphenylamidephytoalexinsinpathogeninfectedbarley AT yukinoriyabuta biosynthesisofphenylamidephytoalexinsinpathogeninfectedbarley AT takujitohnooka biosynthesisofphenylamidephytoalexinsinpathogeninfectedbarley AT kotomiueno biosynthesisofphenylamidephytoalexinsinpathogeninfectedbarley AT shintaketa biosynthesisofphenylamidephytoalexinsinpathogeninfectedbarley AT atsushiishihara biosynthesisofphenylamidephytoalexinsinpathogeninfectedbarley |
_version_ |
1725075318679535616 |