Priming of Defense Systems and Upregulation of MYC2 and JAZ1 Genes after Botrytis cinerea Inoculation in Methyl Jasmonate-Treated Strawberry Fruits

Abstract

Several attempts have been made to study the effects of methyl jasmonate (MeJA) on plants in the past years. However, the comparative effects of the number and phenological time of MeJA applications on the activation of defense systems is currently unknown in strawberries. In the present research, we performed three field treatments during strawberry (Fragaria × ananassa ‘Camarosa’) fruit development and ripening which consisted of differential MeJA applications at flowering (M3), and the large green (M2 and M3) and red ripe (M1, M2, and M3) fruit stages. We also checked changes in gene expression related to plant defense against Botrytis cinerea inoculation post-harvest. In M3 treatment, we observed an upregulation of the anthocyanin and lignin contents and the defense-related genes, encoding for chitinases, β-1,3-glucanases and polygalacturonase-inhibiting proteins, after harvest (0 hpi), along with the jasmonate signaling-related genes FaMYC2 and FaJAZ1 at 48 h after B. cinerea inoculation (48 hpi) during postharvest storage. Although we did not find differences in gray mold incidence between the MeJA treatments and control, these results suggest that preharvest MeJA treatment from the flowering stage onwards (M3) primes defense responses mediated by the upregulation of different defense-related genes and retains the upregulation of MYC2 and JAZ1 at 48 hpi.

The Induced Resistance Lexicon: Do’s and Don’ts

“…Indeed, whether an intense and long-lasting induction of defense pathways, a mainly primed defense response, or an intermediate form is optimal, depends on the cost-benefit balance in a given environment [24]. AO-ISR is fundamentally different from SAR, as the trigger is not a necrotizing pathogen, and the phenotype does not depend on salicylic acid but rather on jasmonic acid and ethylene; c) Pseudomonas simiae WCS417-ISR in Arabidopsis [C. M. J. Pieterse, unpublished]: for this IR phenotype nearly all observed defense responses have been shown to be primed and systemically; d) and e) BABA-IR upon application of low and high doses, respectively [22]: low BABA doses lead to systemically primed defense responses, while high BABA doses lead to directly activated responses mainly in the treated plant parts, these two panels clearly illustrate that for one specific IR trigger, the underlying mechanisms can be different; f) Methyl-jasmonate (MeJa)-IR [58][59][60][61][62][63][64]: via direct activation of defense responses [58][59][60][61][62][63] and via priming [62][63][64], MeJa has been described to activate plant resistance both systemically [58,60] as locally [58,59,63].…”

Interactions of JAZ Repressors with Anthocyanin Biosynthesis-Related Transcription Factors of Fragaria × ananassa

“…Firstly, the phytohormone abscisic acid (ABA) is the major regulator of strawberry ripening promoting the anthocyanin accumulation [13]. Exogenous applications of other phytohormones like jasmonates (JAs) also increase the fruit-associated PAs and anthocyanin contents both in laboratory and field conditions [14][15][16][17]. Secondly, ripe strawberry fruits are rich in anthocyanins, which are synthesized from leucoanthocyanidins by the sequential activity of anthocyanidin synthase (ANS) and uridine diphosphate (UDP) glucose:flavonoid 3-O-glucosyl transferase (UFGT) enzymes [6,18].…”

Jasmonates and Plant Salt Stress: Molecular Players, Physiological Effects, and Improving Tolerance by Using Genome-Associated Tools

“…Exogenous jasmonate applications have effects on different physiological aspects, including protection against biotic and abiotic stresses [ 174 , 175 , 176 ]. Methyl jasmonate (MeJA) application induces protection against oxidative stress as has been reported in different species and conditions [ 176 , 177 , 178 , 179 ].…”