| Title: | Effects of Prohydrojasmon on the Number of Infesting Herbivores and Biomass of Field-Grown Japanese Radish Plants |
| Author(s): | Yoshida K; Uefune M; Ozawa R; Abe H; Okemoto Y; Yoneya K; Takabayashi J; |
| Address: | "Faculty of Agriculture, Meijo University, Nagoya, Japan. Center for Ecological Research, Kyoto University, Otsu, Japan. RIKEN BioResource Research Center, Tsukuba, Japan. Graduate School of Agriculture, Meijo University, Nagoya, Japan. Faculty of Agriculture, Kindai University, Nara, Japan" |
| ISSN/ISBN: | 1664-462X (Print) 1664-462X (Electronic) 1664-462X (Linking) |
| Abstract: | "Prohydrojasmon (PDJ), an analog of jasmonic acid (JA), was found to induce direct and indirect defenses against herbivores in non-infested plants. To test whether PDJ can be used for pest control in crop production, we conducted experiments in pesticide-free Japanese radish fields from October 4 to December 12 in 2015. Twenty-four Japanese radish plants in three plots were treated with a 100 times-diluted commercial formulation (5%) of PDJ (treated plants), and 24 plants in three different plots were treated with water (control plants) until November 29 every week. Throughout the observation period, the number of aphids, leaf-mining fly larvae, vegetable weevils, and thrips was significantly lower on the treated plants than on the control plants. In contrast, the number of lepidopteran larvae was not significantly different between the treated and control plants throughout the study period. Parasitized aphids (mummies) were also observed in both plots. Poisson regression analyses showed that a significantly higher number of mummies was recorded on the treated plants as compared to that on the control plants when the number of aphids increased. This suggested that PDJ application to Japanese radish plants attracted more parasitoid wasps on the treated plants than on the control plants. We also identified eight terpenoids and methyl salicylate as the PDJ-induced plant volatiles in the headspace of the treated plants. Some of these volatiles might be responsible for attracting aphid-parasitoid wasps in the field. However, for other insect pests, we did not find any natural enemies. Interestingly, the genes of the JA and salicylic acid signaling pathways were differentially upregulated in the treated plants. We also observed that the PDJ treatments induced the expression of the genes related to glucosinolate biosynthesis and the subsequent isothiocyanate formation. Additionally, the weights of both the aboveground and belowground parts of the treated plants were significantly lower than those of the respective parts of the control plants. These results indicated that the treatment of Japanese radish plants with a 100 times-diluted commercial formulation of PDJ induced their direct and indirect defenses against several insect pest species to reduce their numbers, and negatively affected their biomass" |
| Keywords: | Raphanus sativus L.var.hortensis Backer aphids leaf-mining fly larvae lepidopteran larvae parasitoids prohydrojasmon thrips vegetable weevils; |
| Notes: | "PubMed-not-MEDLINEYoshida, Kengo Uefune, Masayoshi Ozawa, Rika Abe, Hiroshi Okemoto, Yuka Yoneya, Kinuyo Takabayashi, Junji eng Switzerland 2021/09/04 Front Plant Sci. 2021 Aug 12; 12:695701. doi: 10.3389/fpls.2021.695701. eCollection 2021" |
