title: The possible involvement of salicylic acid and hydrogen peroxide in the systemic promotion of phenolic biosynthesis in clover roots colonized by arbuscular mycorrhizal fungus.
abstract: Arbuscular mycorrhizal fungal (AMF) colonization can induce both the local and the systemic increase in phenolic accumulation in hosts. However, the signaling molecules responsible for the systemic induction is still unclear. In this study, a split-root rhizobox system was designed to explore these molecules, with one half of clover (Trifolium repense) roots colonized by AMF, Funneliformis mosseae (formerly known as Glomus mosseae), and the other not (NM/M). Plants with two halves both (M/M) or neither (NM/NM) inoculated were also established for comparison. The contents of phenols and the accumulation of salicylic acid (SA), hydrogen peroxide (H2O2) and nitric oxide (NO) in roots were monitored, the activities of L-phenylalanine ammonia-lyase (PAL) and nitric oxide synthase (NOS) in roots were assayed, and the expressions of pal and chs (gene encoding chalcone synthase) genes in roots were also quantified using qRT-PCR. Results indicated that when phenolic content in NM/NM plants was lower than that in M/M plants, AMF colonization systemically induced the increase in phenolic content in NM/M plants. Similarly, the accumulations of SA and H2O2 were increased by AMF both locally and systemically, while that of NO was only increased locally. Moreover, enzyme assay and qRT-PCR were in accordance with these results. These data suggest that AMF colonization can systemically increase the phenolic biosynthesis, and SA and H2O2 are possibly the signaling molecules involved. The role of MeSA, a signaling molecule capable of long distance transport in this process, is also discussed.
authors.affiliation: Guangdong Institute of Microbiology, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, State Key Laboratory of Applied Microbiology (Ministry-Guangdong Province Jointly Breeding Base) South China, Guangzhou, China.
authors.forename: Honghui
authors.initials: H
authors.lastname: Zhu
authors.affiliation: College of Horticulture, South China Agricultural University, Guangzhou, China; College of Life Science, Anhui Agricultural University, Hefei, China.
authors.forename: Ruiqin
authors.initials: R
authors.lastname: Zhang
authors.affiliation: College of Horticulture, South China Agricultural University, Guangzhou, China.
authors.forename: Weili
authors.initials: W
authors.lastname: Chen
authors.affiliation: Guangdong Institute of Microbiology, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, State Key Laboratory of Applied Microbiology (Ministry-Guangdong Province Jointly Breeding Base) South China, Guangzhou, China; College of Horticulture, South China Agricultural University, Guangzhou, China.
authors.forename: Zhenhong
authors.initials: Z
authors.lastname: Gu
authors.affiliation: Guangdong Institute of Microbiology, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, State Key Laboratory of Applied Microbiology (Ministry-Guangdong Province Jointly Breeding Base) South China, Guangzhou, China; College of Horticulture, South China Agricultural University, Guangzhou, China.
authors.forename: Xiaolin
authors.initials: X
authors.lastname: Xie
authors.affiliation: College of Life Science, Anhui Agricultural University, Hefei, China.
authors.forename: Haiquan
authors.initials: H
authors.lastname: Zhao
authors.affiliation: Guangdong Institute of Microbiology, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, State Key Laboratory of Applied Microbiology (Ministry-Guangdong Province Jointly Breeding Base) South China, Guangzhou, China; College of Horticulture, South China Agricultural University, Guangzhou, China. Electronic address: yaoqscau@scau.edu.cn.
authors.forename: Qing
authors.initials: Q
authors.lastname: Yao
mesh_terms: D000217:Acyltransferases / Q000235:genetics / Q000378:metabolism; D055137:Glomeromycota / Q000254:growth & development / Q000502:physiology*; D006861:Hydrogen Peroxide / Q000378:metabolism*; D038821:Mycorrhizae / Q000254:growth & development / Q000502:physiology*; D009569:Nitric Oxide / Q000378:metabolism*; D010636:Phenols / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D020156:Salicylic Acid / Q000378:metabolism*; D029921:Trifolium / Q000378:metabolism*
chemical_list: D010636:Phenols; D010940:Plant Proteins; D009569:Nitric Oxide; D006861:Hydrogen Peroxide; D000217:Acyltransferases; C020141:flavanone synthetase; D020156:Salicylic Acid
keywords: Arbuscular mycorrhizal fungus; Hydrogen peroxide; Phenolic accumulation; Salicylic acid; Systemic induction