Getting ready for battle: do cabbage seeds treated with jasmonic acid and chitosan affect chewing and sap‐feeding insects?

Abstract

Induced defence allows plants to manage energy reserves more efficiently by synthesizing defence compounds only when needed. A risk of induced defence is that when plants are challenged by herbivores, they may suffer considerable damage before the defence is mounted. Priming can cause a state of readiness for the induction of the defence response, leading to a reduction in the damage received in an energy-efficient and less costly manner. Our objective was to verify whether seed coating with jasmonic acid (JA) and chitosan (CH) could prime plants against chewing and sap-feeding herbivores by affecting their herbivory of treated plants. We used Brassica oleracea L. var. capitata cv. Derby Day (Brassicaceae) seeds treated with JA and CH, second-instar Plutella xylostella L. (Lepidoptera: Plutellidae), and newborn nymphs of Myzus persicae (Sulzer) (Hemiptera: Aphididae). We evaluated life-history, performance, and fecundity traits of the insects. Neither JA nor CH affected B. oleracea leaf area. Both JA and CH affected P. xylostella. JA reduced the mean relative growth rate of P. xylostella and led to 84% pre-imaginal mortality, whereas CH reduced oviposition. JA reduced significantly the intrinsic rate of increase in M. persicae, whereas CH did not differ from the control. Therefore, JA and CH seed coating lead to long-term defence priming in B. oleracea against chewing and sap-feeding insects.

Transcriptional Reprogramming of Arabidopsis thaliana Defence Pathways by the Entomopathogen Beauveria bassiana Correlates With Resistance Against a Fungal Pathogen but Not Against Insects

“…It is also conceivable that handling the small delicate insects with a soft paintbrush, despite taking great care, might have had some adverse effects. Baseline mortality of P. xylostella seems to vary considerably between 10 and 43% (Haas et al, 2018; Sun et al, 2018). Nevertheless, both endophyte strains caused a significant decrease in the area of necrotic leaf lesions by S. sclerotiorum .…”

Cultivar Variation in Tomato Seed Coat Permeability Is an Important Determinant of Jasmonic Acid Elicited Defenses Against Western Flower Thrips

“…In the past decades, elicitor-mediated induced resistance has become one of the most challenging research areas in plant herbivory. Recent studies have shown that seeds are receptive to direct application of exogenous phytohormones without being constrained by the inherent costs of defense ( Rajjou et al, 2006 ; Worrall et al, 2012 ; Haas et al, 2018 ). However, research on the beneficial effects of JA seed treatments are restricted to one or only few tomato cultivars ( Smart et al, 2013 ).…”

Seed treatment using methyl jasmonate induces resistance to rice water weevil but reduces plant growth in rice

“…Changes in gene expression result, in turn, in the local and systemic production of defense-related metabolites that cause increases in direct and indirect plant resistance to herbivores [1–3]. The well-established role of JA in induced plant defense has led to the suggestion that the JA pathway can be manipulated to protect crops from their insect pests [4–6].…”

“…Another study showed that treatment of cabbage seeds, Brassica oleracea , with JA induced resistance to Plutella xylostella L. and Myzus persicae . Resistance was manifested by reduced growth rates and reduced population growth for caterpillars and aphids, respectively [6]. Additionally, a greenhouse study using seed treatments of MJ and JA on several crops including tomato, cowpea, soybean, and wheat, showed a reduction in nematode infection in cowpea and tomato plants [9].…”

“…One aspect of herbivore or elicitor-induced resistance for which little information is available involves the duration of induced resistance following the initial inducing event [6,12,13]. Underwood (1998) found that resistance induced by Mexican bean beetle feeding in soybean developed within three days of beetle feeding but had completely decayed 15 days after initial injury [14].…”