Jasmonic acid causes short- and long-term alterations to the transcriptome and the expression of defense genes in sugarbeet roots

Abstract

Jasmonic acid (JA) induces native defense responses in plants and increases the resistance of postharvest sugarbeet roots to three common storage-rot causing organisms. To gain insight into the defense responses induced by JA in harvested sugarbeet roots, RNA was isolated from roots treated with water or 10 µM JA and incubated for 2 or 60 d post-treatment. RNA was sequenced, and sequence data was analyzed for short-term (2 d) and long-term (60 d) effects of JA on the sugarbeet root transcriptome. A total of 283 and 326 differentially expressed unigenes were identified in JA-treated roots at 2 and 60 d after treatment, respectively. Of these, more than 96% were uniquely altered in expression at 2 or 60 d, indicating that longterm JA-induced changes to the sugarbeet root transcriptome were substantially different from short-term JA-induced changes. Categorization of differentially expressed unigenes by gene ontology (GO) or Kyoto Encyclopedia of Genes and Genomes (KEGG) identifiers indicated that JA altered expression of a large number of unigenes involved in metabolism, including many unigenes encoding enzymes and unigenes that participate in secondary metabolism. In addition, 88 unigenes, or 15% of all unigenes whose expression were altered by JA, were putatively involved in plant defense. Included were unigenes for pathogenesis-related proteins, regulatory proteins, plant disease resistance proteins, secondary metabolite biosynthetic enzymes, oxidases, and plant cell wall-modifying proteins. Detailed, time-course expression analysis of 19 JA-altered defense unigenes revealed similarities in expression for three plant disease resistant (R) genes and three laccase genes, indicating possible co-regulation of these genes. No relationships, however, were observed between enzyme activities and transcript levels for any of four major families of upregulated defense genes for which enzyme activities Fugate et al., p. 3 were determined, consistent with JA functioning as a primer, rather than an inducer, of plant defenses. Overall, this research supports JA's role as a signaling molecule for plant defense and provides evidence that a variety of defense mechanisms, including the production of antifungal and antimicrobial compounds, stimulation of antioxidant defenses, and stiffening and strengthening of cell walls, may contribute to JA-induced storage rot resistance in sugarbeet roots.

<i>n</i>-Propyl dihydrojasmonates influence ethylene signal transduction in infected apple fruit by <i>Botrytis cinerea</i>

“…JA application inhibited postharvest pathogens in fruit such as loquats, sugarbeet roots (Beta vulgaris), grapes, peaches, and apricots (Cao et al, 2008;Fugate et al, 2012;Nimitkeatkai et al, 2011;Wang et al, 2015a;Yao and Tian, 2005). Fugate et al (2017) found that MeJA application upregulated genes for PR proteins as a defense response in sugar beet roots. In our study, the JA concentrations increased in the PDJ + Ino + group, whilst the expression levels of MdAOS1 also increased.…”

Integrated soybean transcriptomics, metabolomics, and chemical genomics reveal the importance of the phenylpropanoid pathway and antifungal activity in resistance to the broad host range pathogenSclerotinia sclerotiorum

“…JA signaling have been linked to the alteration of plant secondary metabolites, including alkaloids, terpenoids, flavonoids, phenolic compounds, and phytoalexins (75–79). Secondary metabolites derived from multiple branches of the phenylpropanoid pathway, including lignins, isoflavonoid-phytoalexins, and other phenolic compounds have also been proposed as important components of defense responses (38,39).…”

Methyl jasmonate: a phytohormone with potential for the treatment of inflammatory bowel diseases

“…The phytohormone MeJA has been characterized as a vital cellular regulator involved in a number of dynamic processes, linked to the development of active responses in the defence against biotic and abiotic stresses . It is also active in processes closely linked to oxidative stress, regulating the activity of antioxidant enzymes …”

“…[30] The phytohormone MeJA has been characterized as a vital cellular regulator involved in a number of dynamic processes, linked to the development of active responses in the defence against biotic and abiotic stresses. [31,42] It is also active in processes closely linked to oxidative stress, regulating the activity of antioxidant enzymes. [43] Some plants contain relatively high levels of circulating MeJA: the olive tree, species of the Jasminum genus, the orchid Cymbidium goeringii, the tuberose (Polianthes tuberosa), Chloranthus spicatus, Ginger, Boronia megastigma, honeysuckle (Lonicera japonica), Artemisia tridentate and rosemary (Rosmarinus officinalis).…”