TY - JOUR
T1 - Agrobacterium tumefaciens Enhances Biosynthesis of Two Distinct Auxins in the Formation of Crown Galls
AU - Mashiguchi, Kiyoshi
AU - Hisano, Hiroshi
AU - Takeda-Kamiya, Noriko
AU - Takebayashi, Yumiko
AU - Ariizumi, Tohru
AU - Gao, Yangbin
AU - Ezura, Hiroshi
AU - Sato, Kazuhiro
AU - Zhao, Yunde
AU - Hayashi, Ken Ichiro
AU - Kasahara, Hiroyuki
N1 - Funding Information:
We thank Dr. Barbara Kunkel and Dr. Sam Cook for critical reading of the manuscript, Dr. Javier Sampedro for generously sharing the pERV1-hyg vector, Dr. Atsushi Higashitani and Dr. Ken Komatsu for helpful suggestions, Dr. Hitoshi Sakakibara for generously sharing a cDNA of iaaM gene, and Ms. Aya Ide for excellent technical assistance. This study was supported by the Ministry of Education, Culture, Sports, Science and Technology (MEXT) as part of the Joint Research Program implemented at the Institute of Plant Science and Resources, Okayama University in Japan. Barley and tomato seeds were provided by the National Bioresource Project of the MEXT in Japan.
Funding Information:
This study was supported by the Japan Science and Technology Agency (JST) [PRESTO], Japan Society for the Promotion of Science (JSPS) KAKENHI [JP18H02457] to H.K., and National Institute of Health (NIH) grant [R01GM114660] to Y.Z.
Publisher Copyright:
© 2018 The Author(s).
PY - 2019/1/1
Y1 - 2019/1/1
N2 - The plant pathogen Agrobacterium tumefaciens infects plants and introduces the transferred-DNA (T-DNA) region of the Ti-plasmid into nuclear DNA of host plants to induce the formation of tumors (crown galls). The T-DNA region carries iaaM and iaaH genes for synthesis of the plant hormone auxin, indole-3-acetic acid (IAA). It has been demonstrated that the iaaM gene encodes a tryptophan 2-monooxygenase which catalyzes the conversion of tryptophan to indole-3-acetamide (IAM), and the iaaH gene encodes an amidase for subsequent conversion of IAM to IAA. In this article, we demonstrate that A. tumefaciens enhances the production of both IAA and phenylacetic acid (PAA), another auxin which does not show polar transport characteristics, in the formation of crown galls. Using liquid chromatography-tandem mass spectroscopy, we found that the endogenous levels of phenylacetamide (PAM) and PAA metabolites, as well as IAM and IAA metabolites, are remarkably increased in crown galls formed on the stem of tomato plants, implying that two distinct auxins are simultaneously synthesized via the IaaM-IaaH pathway. Moreover, we found that the induction of the iaaM gene dramatically elevated the levels of PAM, PAA and its metabolites, along with IAM, IAA and its metabolites, in Arabidopsis and barley. From these results, we conclude that A. tumefaciens enhances biosynthesis of two distinct auxins in the formation of crown galls.
AB - The plant pathogen Agrobacterium tumefaciens infects plants and introduces the transferred-DNA (T-DNA) region of the Ti-plasmid into nuclear DNA of host plants to induce the formation of tumors (crown galls). The T-DNA region carries iaaM and iaaH genes for synthesis of the plant hormone auxin, indole-3-acetic acid (IAA). It has been demonstrated that the iaaM gene encodes a tryptophan 2-monooxygenase which catalyzes the conversion of tryptophan to indole-3-acetamide (IAM), and the iaaH gene encodes an amidase for subsequent conversion of IAM to IAA. In this article, we demonstrate that A. tumefaciens enhances the production of both IAA and phenylacetic acid (PAA), another auxin which does not show polar transport characteristics, in the formation of crown galls. Using liquid chromatography-tandem mass spectroscopy, we found that the endogenous levels of phenylacetamide (PAM) and PAA metabolites, as well as IAM and IAA metabolites, are remarkably increased in crown galls formed on the stem of tomato plants, implying that two distinct auxins are simultaneously synthesized via the IaaM-IaaH pathway. Moreover, we found that the induction of the iaaM gene dramatically elevated the levels of PAM, PAA and its metabolites, along with IAM, IAA and its metabolites, in Arabidopsis and barley. From these results, we conclude that A. tumefaciens enhances biosynthesis of two distinct auxins in the formation of crown galls.
KW - Agrobacterium tumefaciens
KW - Auxin
KW - Crown gall
KW - Indole-3-acetic acid
KW - Phenylacetic acid
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U2 - 10.1093/pcp/pcy182
DO - 10.1093/pcp/pcy182
M3 - Article
C2 - 30169882
AN - SCOPUS:85060654431
SN - 0032-0781
VL - 60
SP - 29
EP - 37
JO - Plant and Cell Physiology
JF - Plant and Cell Physiology
IS - 1
ER -