Plant Growth Promoting Rhizobacteria (PGPR) and Plutella xylostella (L.) (Lepidoptera: Plutellidae) interaction as a resistance inductor factor in Brassica oleracea var. capitata

Abstract

Resistance of Plutella xylostella populations to chemical insecticides has made its management difficult, and the utilization of resistant cabbage cultivars has been shown to be a useful alternative. The objective of this study was to demonstrate the induction of cabbage plant resistance to P. xylostella using PGPR and injuries caused by the pest larvae as elicitors. Therefore, we evaluated the insects' responses utilizing a specific bioassay. Furthermore, this assay was used for selecting a PGPR strain that affects the insect's biology, and to examine molecular and biochemical responses of the plants influenced by the plantmicrobe-insect interaction. Among the strains used in this study, Kluyvera ascorbata showed the most relevant results by influencing biological characteristics of the insect. Thus, the following tests demonstrated that the cited strain possesses a high influence on plant metabolism when it undergoes different types of stress such as injuries caused by the pest. These findings were determined from the different responses obtained by the chemical analyses of the tested plants and from the differentiation in the genetic sequences obtained from plants inoculated with or without PGPR that were injured by the pest. The PGPR K. ascorbata alters the metabolism of cabbage plants, which directs a specific plant defense against P. xylostella.

Tripartite interactions between Brassica oleracea, soil microbes and shoot- and root feeding insects

“…Several studies have examined the seed bio-priming method to enhance yield or biomass production (Raj et al, 2004;Abuamsha et al, 2011b;Manrique et al, 2019), yet few studies have included plant resistance to insect herbivores (Crialesi et al, 2017;Thuler et al, 2017). Therefore, we investigated cabbage bacterization effects on plant biomass and resistance to three common insect herbivores of cabbage plants.…”

“…Interestingly, a few other bacteria-plant-insect systems show a systemic negative effect from rhizobacterial inoculation on leaf area consumed by insects (Zehnder et al, 1997;Commare et al, 2002;Saravanakumar et al, 2008). For example, leaf area consumed by P. xylostella was negatively affected, after B. oleracea seed inoculation with endophytic Kluyvera ascorbata EN4, when the insects fed on detached leaves (Crialesi et al, 2017). On the other hand, neutral effects from microbes have previously also been recorded, where consumed leaf area by Spodoptera littoralis was not affected by presence of soil microbes in the soil of maize plants (D'Alessandro et al, 2014).…”