title: Cotton S-adenosylmethionine decarboxylase-mediated spermine biosynthesis is required for salicylic acid- and leucine-correlated signaling in the defense response to Verticillium dahliae.
abstract: Cotton S-adenosylmethionine decarboxylase-, rather than spermine synthase-, mediated spermine biosynthesis is required for salicylic acid- and leucine-correlated signaling in the defense response to Verticillium dahliae. Spermine (Spm) signaling is correlated with plant resistance to the fungal pathogen Verticillium dahliae. We identified genes for key rate-limiting enzymes in the biosynthesis of Spm, namely S-adenosylmethionine decarboxylase (GhSAMDC) and Spm synthase (GhSPMS). These were found by screening suppression subtractive hybridization and cDNA libraries of cotton (Gossypium) species tolerant to Verticillium wilt. Both were induced early and strongly by inoculation with V. dahliae and application of plant hormones. Silencing of GhSPMS or GhSAMDC in cotton leaves led to a significant accumulation of upstream substrates and, ultimately, enhanced plant susceptibility to Verticillium infection. Exogenous supplementation of Spm to the silenced cotton plants improved resistance. When compared with the wild type (WT), constitutive expression of GhSAMDC in Arabidopsis thaliana was associated with greater Verticillium wilt resistance and higher accumulations of Spm, salicylic acid, and leucine during the infection period. By contrast, transgenic Arabidopsis plants that over-expressed GhSPMS were unexpectedly more susceptible than the WT to V. dahliae and they also had impaired levels of putrescine (Put) and salicylic acid (SA). The susceptibility exhibited in GhSPMS-overexpressing Arabidopsis plants was partially reversed by the exogenous supply of Put or SA. In addition, the responsiveness of those two transgenic Arabidopsis lines to V. dahliae was associated with an alteration in transcripts of genes involved in plant resistance to epidermal penetrations and amino acid signaling. Together, these results suggest that GhSAMDC-, rather than GhSPMS-, mediated spermine biosynthesis contributes to plant resistance against V. dahliae through SA- and leucine-correlated signaling.
authors.affiliation: North China Key Laboratory for Germplasm Resources of Education Ministry, Hebei Agricultural University, Baoding, 071001, China.
authors.forename: Hui-Juan
authors.initials: HJ
authors.lastname: Mo
authors.affiliation: Institute of Genetics and Breeding, Langfang Teachers University, Langfang, 065000, China.
authors.forename: Yan-Xiang
authors.initials: YX
authors.lastname: Sun
authors.affiliation: North China Key Laboratory for Germplasm Resources of Education Ministry, Hebei Agricultural University, Baoding, 071001, China.
authors.forename: Xiao-Li
authors.initials: XL
authors.lastname: Zhu
authors.affiliation: North China Key Laboratory for Germplasm Resources of Education Ministry, Hebei Agricultural University, Baoding, 071001, China.
authors.forename: Xing-Fen
authors.initials: XF
authors.lastname: Wang
authors.affiliation: North China Key Laboratory for Germplasm Resources of Education Ministry, Hebei Agricultural University, Baoding, 071001, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: North China Key Laboratory for Germplasm Resources of Education Ministry, Hebei Agricultural University, Baoding, 071001, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Yang
authors.affiliation: North China Key Laboratory for Germplasm Resources of Education Ministry, Hebei Agricultural University, Baoding, 071001, China.|School of Plant Biology, Faculty of Science and The UWA Institute of Agriculture, The University of Western Australia, Perth, 6009, Australia.
authors.forename: Gui-Jun
authors.initials: GJ
authors.lastname: Yan
authors.affiliation: North China Key Laboratory for Germplasm Resources of Education Ministry, Hebei Agricultural University, Baoding, 071001, China. mzhy@hebau.edu.cn.
authors.forename: Zhi-Ying
authors.initials: ZY
authors.lastname: Ma
mesh_terms: D012437:Adenosylmethionine Decarboxylase / Q000235:genetics / Q000378:metabolism*; D017360:Arabidopsis / Q000235:genetics / Q000382:microbiology; D060467:Disease Resistance / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D003368:Gossypium / Q000378:metabolism* / Q000382:microbiology*; D007930:Leucine / Q000378:metabolism; D010935:Plant Diseases / Q000382:microbiology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D011700:Putrescine / Q000378:metabolism; D020156:Salicylic Acid / Q000378:metabolism; D013096:Spermine / Q000096:biosynthesis* / Q000378:metabolism; D013097:Spermine Synthase / Q000235:genetics / Q000378:metabolism; D020172:Verticillium / Q000472:pathogenicity*
chemical_list: D010940:Plant Proteins; D013096:Spermine; D013097:Spermine Synthase; D012437:Adenosylmethionine Decarboxylase; D007930:Leucine; D020156:Salicylic Acid; D011700:Putrescine
keywords: Cotton; Fungal pathogen; Leucine; Polyamines; S-adenosylmethionine decarboxylase; Salicylic acid; Spermine; Verticillium wilt resistance