Methyl jasmonate elicits rapid changes in carbon and nitrogen dynamics in tomato

Abstract

Summary• Evidence is emerging to support the notion that in response to herbivory, plants undergo changes in their primary metabolism and are able to fine-tune the allocation of new and existing resources and temporarily direct them to storage organs.• We hypothesized that simulated herbivory increases the export of resources out of the affected tissues and increases allocation to roots. We used short-lived radioisotopes to study in vivo the dynamics of newly incorporated 11 CO 2 and 13 NH 3 .Methyl jasmonate (MeJA), a known defense elicitor, was applied to the foliage of tomato plants and 4 h later we monitored leaf uptake, export and whole-plant allocation of [ 11 C]photosynthate and [ 13 N]amino acids.• There was a marginally significant decrease in the fixation of 11 CO 2 , and an increase in the export of newly acquired carbon and nitrogen out of MeJA-treated leaves. The proportion of nitrogen allocated to roots increased, whereas the proportion of carbon did not change.• These results are in agreement with our hypotheses, showing a change in the allocation of resources after treatment with MeJA; this may reduce the chance of resources being lost to herbivores and act as a buffer to biotic stress by increasing the potential for plant regrowth and survival after the attack.

Is polyphenol induction simply a result of altered carbon and nitrogen accumulation?

“…7,[10][11][12][13] Taken together, our results indicate that sink-source relationships must frequently determine local CHO/N ratios. Many have noted an inverse relationship in entire plants between N availability and the constitutive concentration of CHO-based metabolites, especially polyphenols.…”

“…2-8 We have found that both insect grazing and exogenous jasmonate (JA) trigger increased sink strength, including a 3-fold increase in the import of 13 C-labeled CHOs from orthostichously linked source leaves to sink leaves in poplar saplings. 1,3,4 We recently found that unlike carbon import, nitrogen translocation was not increased by JA treatment in poplar saplings.…”

Cascading effects of induced terrestrial plant defences on aquatic and terrestrial ecosystem function

“…There are many scenarios that could explain the decrease in N, some of which directly involve plant defence, while others are more indirect consequences of herbivory stress. Several possible explanations include: alders released N-containing volatile emissions in response to herbivory (such as methyl anthranilate and indole) [40], methyl jasmonate or the herbivory stress as a whole interfered with or deprioritized nitrogen fixation [41], or N was shunted out of the leaves into other parts of the plant (such as the roots) as a means of resource protection and/or to dissuade further herbivory [42]. The physiological responses resulting in the increased C : N among the herbivory treated trees are quite possibly different among the fertilized versus unfertilized trees (plants growing on N-poor soils often use C-based defences and vice versa) [43].…”

Consequences of combined herbivore feeding and pathogen infection for fitness of Barbarea vulgaris plants

“…This was measured as total nitrogen, and may reflect the increase in glucosinolate 392 content when exposed to herbivory. Gomez et al (2010) have shown that nitrogen may be re-393 allocated to other parts of the plant upon herbivory as a strategy to preserve nitrogen for re-394 growth. Whether this was the case for B. vulgaris we cannot determine as roots were not 395 analysed.…”