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Bacterial microbe-associated molecular patterns (MAMPs) play an important role in innate plant immunity. This in vitro study evaluated the putative role of protein elicitor PeBA1 derived from Bacillus amyloliquefaciens NC6 strain in eliciting induced resistance type responses in common bean (Phaseolus vulgaris) plants against green peach aphid Myzus persicae. Nymphal developmental time of aphids was significantly prolonged and the fecundity was significantly reduced by different concentrations of PeBA1 elicitor (i.e. 40.51, 24.91 and 16.38 μg mL-1) applied at three different temperature regimes (i.e. 21, 27 and 30 ℃). Moreover, foliar application of PeBA1 elicitor protein strongly up-regulated the expression levels of salicylic acid (SA) pathway-associated genes, while the expression levels of jasmonic acid (JA) pathwayassociated genes exhibited a moderate induction. Quantification by LC/MSMS revealed a linear increase of both SA and JA plant defense hormones along with the time of exposure. Our findings suggest that the bacterial elicitor protein PeBA1 could be used as an effective biological pest management tool against phloem-feeding insect pests such as green peach aphids M. persicae. [ABSTRACT FROM AUTHOR]

Elicitors are biofactors that induce resistance in plants against different insect pests. This in vitro study evaluated the impact of a novel elicitor protein PeBC1, extracted from a necrotrophic fungus Botrytis cinerea, on the development and fecundity parameters of green peach aphid (Myzus persicae) on common beans (Phaseolus vulgaris L.). Three different concentrations of PeBC1 elicitor (i.e., 33.56, 25.43, 19.33 µg mL−1) were applied at three different temperature regimes (i.e., 18, 21, and 25 °C). Elicitor treatments were applied topically on the bean plants at 3-leaf stage and newly emerged (0⁻6 h old) apterous adult aphids were exposed to these treated leaves. In addition to the biological parameters of aphids, the relative expression levels of key genes associated with jasmonic acid (JA) and salicylic acid (SA) plant defense pathways were also determined through RT-qPCR. Results of bioassays revealed that the application of PeBC1 elicitor protein exhibited pronounced and significant (p < 0.05) sub-lethal effects on green peach aphids. The fecundity was reduced and the nymphal development time was prolonged by different concentrations of PeBC1 elicitor and temperature regimes. Gene expression studies showed that the exogenous application of PeBC1 induced a significant upregulation of the expression levels of JA and SA pathway-associated genes in bean plants. As compared to control, elicitor-treated plants exhibited an induced resistance against aphids. Our findings suggest the potential use of PeBC1 elicitor protein in future bio-intensive management strategies against sap-sucking insect pests such as green peach aphids.

• Lecanicillium lecanii protein induced Myzus persicae resistance in plants. • Survival of M. persicae was reduced by us foliar application of fungal protein. • Fecundity of M. persicae was reduced by fungal protein. • Salicylic acid and jasmonic acid pathway-associated key genes were upregulated. • L. lecanii derived elicitor protein could be a biological pest management tool. Many biotrophic and necrotrophic fungi synthesize proteins that may elicit induced plant resistance against different herbivore pests. This in-vitro study elucidates the sub-lethal effect of a partially-purified protein derived from the entomopathogenic fungus Lecanicillium lecanii (Zimmerman) (Hypocreales: Clavicipitaceae) against green peach aphid Myzus persicae (Sulzer) (Hemiptera: Aphididae), an economically important pest of many solanaceous crops including tomato. Bioassays were conducted to determine the impact of different concentrations of protein (i.e. 0.018, 0.036 and 0.054 µM) on the survival and fecundity of M. persicae on tomato (Lycopersicon esculentum) plants. Moreover, the potential role of this exogenous protein in the plant defense mechanism was assessed by expression analyses of key genes associated with salicylic acid (SA) and jasmonic acid (JA) pathways using RT-qPCR. The results indicated a significant negative effect of all protein concentrations on the survivorship and fecundity of M. persicae. The highest concentration (0.054 µM) resulted in lowest survival (46%) of aphids at 7th day post-treatment, while two other concentrations (0.036 and 0.018 µM) resulted in 61 and 71% survival rate, respectively. Similarly, lowest and highest mean fecundity rates were recorded for the highest protein concentration and the control (1.5 and 2.4 nymphs day−1 female−1), respectively. Moreover, L. lecanii -derived protein strongly upregulated the SA associated genes PR1, BGL2 and PAL, and moderately upregulated the JA associated genes LOX, AOS and AOC in protein-treated tomato plants compared to the control plants. These findings demonstrate the systemic resistance induced in tomato plants against M. persicae by the exogenous application of partially-purified protein extracted from L. lecanii , suggesting its further purification and characterization as a novel biological pest management tool against aphids and other phloem-feeding insect pests. [ABSTRACT FROM AUTHOR]

Elicitors are biofactors that induce resistance in plants against different insect pests. This in vitro study evaluated the impact of a novel elicitor protein PeBC1, extracted from a necrotrophic fungus Botrytis cinerea, on the development and fecundity parameters of green peach aphid (Myzus persicae) on common beans (Phaseolus vulgaris L.). Three different concentrations of PeBC1 elicitor (i.e., 33.56, 25.43, 19.33 µg mL−1) were applied at three different temperature regimes (i.e., 18, 21, and 25 °C). Elicitor treatments were applied topically on the bean plants at 3-leaf stage and newly emerged (0–6 h old) apterous adult aphids were exposed to these treated leaves. In addition to the biological parameters of aphids, the relative expression levels of key genes associated with jasmonic acid (JA) and salicylic acid (SA) plant defense pathways were also determined through RT-qPCR. Results of bioassays revealed that the application of PeBC1 elicitor protein exhibited pronounced and significant (p < 0.05) sub-lethal effects on green peach aphids. The fecundity was reduced and the nymphal development time was prolonged by different concentrations of PeBC1 elicitor and temperature regimes. Gene expression studies showed that the exogenous application of PeBC1 induced a significant upregulation of the expression levels of JA and SA pathway-associated genes in bean plants. As compared to control, elicitor-treated plants exhibited an induced resistance against aphids. Our findings suggest the potential use of PeBC1 elicitor protein in future bio-intensive management strategies against sap-sucking insect pests such as green peach aphids. [ABSTRACT FROM AUTHOR]