Biology subjects

Belles, J. M.

Publications and source records attributed to Belles, J. M..

2 recordsLinked to original sources

bioRxiv2023

Metabolic crosstalk between hydroxylated monoterpenes and salicylic acid in tomato defence response against Pseudomonas syringae pv tomato

Hydroxylated monoterpenes (HMTPs) are differentially emitted by tomato plants efficiently resisting a bacterial infection. We have studied the defensive role of these volatiles in the tomato response to bacteria, whose main entrance are stomata apertures. Treatments with some HMTPs resulted in stomatal closure and PR1 induction. Particularly, -terpineol induced stomatal closure in a salicylic (SA) and abscisic acid-independent manner, and conferred resistance to bacteria. Interestingly, transgenic tomato plants overexpressing or silencing the monoterpene synthase MTS1, which displayed alterations in the emission of HMTPs, exhibited changes in the stomatal aperture but not in plant resistance. Measures of both 2-C-methyl-D-erythritol-2,4-cyclopyrophosphate (MEcPP) and SA levels, revealed a competition for MEcPP by the methylerythritol phosphate (MEP) pathway and the SA biosynthesis activation, thus explaining the absence of phenotype in transgenic plants. These results were confirmed by chemical inhibition or activation of the MEP pathway. Besides, treatments with BTH, a SA functional analogue, conferred enhanced resistance in transgenic tomato plants overexpressing MTS1. Finally, plants overexpressing MTS1 induced PR1 and stomata closure in neighbouring plants. Our results confirm the role of HMTPs in both intra and inter-plant immune signalling, and reveal a metabolic crosstalk between the MEP and SA pathways in tomato plants. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=124 SRC="FIGDIR/small/539605v2_ufig1.gif" ALT="Figure 1"> View larger version (19K): org.highwire.dtl.DTLVardef@1048cddorg.highwire.dtl.DTLVardef@1bc1948org.highwire.dtl.DTLVardef@1ff0eaorg.highwire.dtl.DTLVardef@101c4fa_HPS_FORMAT_FIGEXP M_FIG Metabolic crosstalk between hydroxylated monoterpenes and salicylic acid in tomato defence response against Pseudomonas syringae pv tomato. Created with BioRender.com. C_FIG

plant biology↗

bioRxiv2022

SlS5H silencing reveals specific pathogen-triggered salicylic acid metabolism in tomato

The phytohormone salicylic acid (SA or 2-hydroxybenzoic acid) plays an important role in plant biotic and abiotic responses. Gentisic acid (GA or 2,5-Dihydroxybenzoic acid, 2,5-DHBA) is the product of the SA 5-hydroxylation which is catalysed by the S5H enzyme, also known as DMR6. GA has been described to accumulate at high levels in compatible plant-pathogen interactions such as tomato plants infected by Citrus Exocortis Viroid (CEVd), and to a much lesser extend upon Pseudomonas syringae DC3000 pv. tomato (Pst) infection. Here we describe the specific effect that tomato SlS5H impairment produces on both plant-pathogen interactions. The induction of SlS5H in tomato plants by different pathogens was corroborated by qRT-PCR and correlated with previously described 2,5-DHBA accumulations. Transient SlS5H over-expression assays in Nicotiana benthamiana confirmed that SA is a substrate for SlS5H in vivo. RNAi_SlS5H tomato transgenic plants were generated and characterized upon CEVd and Pst infections. Transgenic tomato plants displayed an activation of defences and therefore a loss of susceptibility against both pathogens, and alternative SA homeostasis seems to occur for each specific interaction. Metabolomic assays revealed that whilst the glycosylated form of SA was the most discriminant metabolite found in CEVd infected RNAi_SlS5H transgenic plants, trans-feruloyldopamine, feruloylquinic acid, feruloylgalactarate and 2-hydroxyglutarate were the most accumulated compounds in the Pst-infected transgenic tomato leaves. Transgenic lines also displayed hyper susceptibility to Botrytis cinerea, as well as a smaller size and early senescence. Collectively, our results reveal a novel mechanism by which tomato plants specifically set SA homeostasis upon different pathogen attacks. One sentence summaryThe impairment of SA hydroxylation in tomato plants uncovers specific SA homeostasis upon CEVd or Pseudomonas syringae infections.

biochemistry↗