Metabolic Mechanism of Plant Defense against Rice Blast Induced by Probenazole

Abstract

The probenazole fungicide is used for controlling rice blast (Magnaporthe grisea) primarily by inducing disease resistance of the plant. To investigate the mechanism of induced plant defense, rice seedlings were treated with probenazole at 15 days post emergence, and non-treated plants were used for the control. The plants were infected with M. grisea 5 days after chemical treatment and incubated in a greenhouse. After 7 days, rice seedlings were sampled. The metabolome of rice seedlings was chemically extracted and analyzed using gas chromatography and mass spectrum (GC-MS). The GC-MS data were processed using analysis of variance (ANOVA), principal component analysis (PCA) and metabolic pathway elucidation. Results showed that probenazole application significantly affected the metabolic profile of rice seedlings, and the effect was proportionally leveraged with the increase of probenazole concentration. Probenazole resulted in a change of 54 metabolites. Salicylic acid, γ-aminobutyrate, shikimate and several other primary metabolites related to plant resistance were significantly up-regulated and some metabolites such as phenylalanine, valine and proline were down-regulated in probenazole-treated seedlings. These results revealed a metabolic pathway of rice seedlings induced by probenazole treatment regarding the resistance to M. grisea infection.

Chemical induction of leaf senescence and powdery mildew resistance involves ethylene-mediated chlorophyll degradation and ROS metabolism in cucumber

“…The plant defense elicitor PBZ induces disease resistance in various plant species [ 17 , 20 , 24 – 26 ]. We were curious to test whether PBZ could improve powdery mildew resistance in cucumber.…”

“…PBZ improves disease resistance in crops such as maize, rice, and wheat [ 20 , 24 , 26 ]. However, to the best of our knowledge, there have been no reports on the application of PBZ in cucumber.…”

“…In Arabidopsis , PBZ specifically activates SA biosynthesis/signaling through the ISOCHORISMATE SYNTHASE 1 (ICS1)–NPR1 cascade, inducing systemic acquired resistance (SAR) [ 17 , 18 ]. PBZ and its metabolic derivative saccharin increase the synthesis of JA and enhance the disease resistance of rice and wheat [ 19 , 20 ]. Interestingly, both JA- and ET-responsive cis- elements mediate the response to PBZ treatment, suggesting that PBZ may act through multiple phytohormone signaling pathways [ 21 ].…”

“…Powdery mildew caused by Podosphaera xanthii is a major disease in cucumber, commonly influencing leaf senescence and heavily affecting yield and nutritional quality [ 22 , 23 ]. Although the role and mode of action of PBZ in inducing disease resistance and leaf senescence have been investigated extensively in various plant species (including rice, Arabidopsis , wheat, maize, and tobacco), its efficacy has not been tested on cucurbitaceous crops [ 17 , 20 , 24 – 26 ]. Here, we report the unexpected finding that PBZ activates the ET biosynthesis and signaling pathway in cucumber, in contrast to the SA pathway in Arabidopsis [ 17 , 27 ].…”

Dynamic Changes in Plant Secondary Metabolites Induced by Botrytis cinerea Infection

“…The sampled seedlings were processed for metabolomic analysis following the previously reported procedure [ 22 ]. Briefly, the sample was prechilled with liquid nitrogen and ground in a ball mill (MM400; Verder Shanghai Instruments and Equipment Co., Ltd., Shanghai, China) at 30 Hz for 1 min.…”