Elicitor Application in Strawberry Results in Long-Term Increase of Plant Resilience Without Yield Loss

Abstract

For a first step integrating elicitor applications into the current IPM strategy increasing plant resilience against pests, we investigated repeated elicitor treatments in a strawberry everbearer nursery and cropping cycle under glass. During nursery methyl-jasmonate (MeJA), testing induction of defenses with plant bioassays was applied every 3 weeks. Thrips damage and reproduction by spider mites, whitefly and aphids were strongly reduced upon elicitor treatment. Subsequently, we applied MeJA every 3 weeks or based on scouting pests during a whole cropping cycle. Thrips leaf bioassays and LC-MS leaf metabolomics were applied to investigate the induction of defenses. Leaf damage by thrips was lower for both MeJA application schemes compared to the control except for the last weeks. While elicitor treatments after scouting also reduced damage, its effect did not last. Thrips damage decreased from vegetative to mature plants during the cropping cycle. At the end of the nursery phase, plants in the elicitor treatment were smaller. Surprisingly, growth during production was not affected by MeJA application, as were fruit yield and quality. LC-MS leaf metabolomics showed strong induction of vegetative plants decreasing during the maturation of plants toward the end of cultivation. Concurrently, no increase in the JA-inducible marker PPO was observed when measured toward the end of cultivation. Mostly flavonoid and phenolic glycosides known as plant defense compounds were induced upon MeJA application. While induced defense decreased with the maturation of plants, constitutive defense increased as measured in the leaf metabolome of control plants. Our data propose that young, relatively small plant stages lack constitutive defense necessitating an active JA defense response. As plants, mature constitutive defense metabolites seem to accumulate, providing a higher level of basal resistance. Our results have important implications for but are not limited to strawberry cultivation. We demonstrated that repeated elicitor application could be deployed as part of an integrated approach for sustainable crop protection by vertical integration with other management tactics and horizontal integration to control multiple pests concurrently. This approach forms a promising potential for long-term crop protection in greenhouses.

Plant Growth-Promoting Rhizobacteria Enhance Defense of Strawberry Plants Against Spider Mites

“…For example, Steinite and Levinsh (2002 , 2003) showed that induced resistance in strawberry, indicated by increased polyphenol oxidase, which is an important JA-inducible marker, negatively affected reproduction of T. urticae . Mouden et al (2021) reported that induction of the JA pathway enhanced strawberry plant defense against T. urticae via increased production of phenolic acids, flavonoid compounds and anthocyanins. Similarly, Luczynski et al (1990) observed that the development of T. urticae correlated negatively with foliar concentrations of phenolics.…”

Proactive application of UV-B light could immunize strawberry fruits against gray mold (Botrytis cinerea) postharvest

“…Jasmonic acid and its biologically active derivatives (collectively known as jasmonates or JAs) are essential molecular tools in shaping the defensive response to a broad spectrum of pathogens and insects (Hazman et al, 2019;Mouden et al, 2021). (Qi et al, 2018) reported that UV-B exposure for five days significantly elevated jasmonic acid hormone (JA) and synthesizing genes expression as AtOPR3 in Arabidopsis, and NtAOC, OsLOX, and ZmJAR1 in tobacco, rice, and maize, respectively.…”

Natuurvriendelijke bestrijding vanbladluizen in de glastuinbouw : Een overzicht van bestaande en nieuwe methoden van bestrijding

“…Deze chemische elicitor zorgt ervoor dat planten sneller de jasmonzuurverdedigingsroute aanschakelen waardoor er sneller en meer secundaire metabolieten worden aangemaakt die de groei van insecten remmen. Ook in aardbei bleek deze elicitor langdurig de ontwikkeling van bladluis te remmen (Mouden et al 2021). Een recente Chinese studie liet zien dat de elicitor salicylzuur in graan de verdediging tegen graanluis kan verhogen, wat resulteerde in een significante lagere groeisnelheid (Feng et al 2021).…”

“…Deze chemische elicitors bieden dus wellicht mogelijkheden om de plantweerbaarheid tegen bladluis te verhogen. In de recente studie van de WUR bleek toepassing van MeJa in aardbei geen effecten te hebben op de opbrengst (Mouden et al 2021).…”