The Role And Mechanism Of N-Acylethanolamines Metabolism In Tomato Defense Against Botrytis Cinerea

Along with development of horticultural production, occurrence of bacterial, viral and fungic diseases in plants cultivation becomes more frequently, and often induces large-area of economical losses. Fungal diseases are very common among them and accounts for about 70～80% in plant diseases. The gray mold is one of the most serious disease with tomato cultivation, which develops rapidly in recent years. Gray mould is popular in many kinds of vegetables and can cause 40～50% or even more production loss. While the resistant germplasm have never been found, pesticide application are now widely used to control the B. cinerea diseases. However, it may cause resistance to pesticides and posing threat to the sustainable environment and food safety. N-Acylethanolamines (NAEs) has been characterized as lipid mediators in the plants and animal kingdoms and has been found play a role in physiological metabolic activity, seed germination, and so on. It remains largely unknown whether NAEs play a role in plant-pathogen interaction. In this study, the role and mechanism of N-Acylethanolamines metabolism in plant defense against B. cinerea were studied in tomato(Solanum lycopersicum L.) plants. The main results are as follows:1. The response and role of N-Acylethanolamines metabolism in tomato-B. cinerea interaction were studied. N-Acylethanolamines (NAEs) are fatty acid derivates in plants, showing the important roles in various plant physiological processes. The results showed that B. cinerea infection resulted in evident and significantrelative gene expression changes of PLD3, PLD6, FAAH1 and FAAH11. The incidence of grey mould were reduced to 30%～50% with exogenous NAE18:2, NAE18:0 and NAE22:5 treaments. Among them, NAE18:2 has the best effect on tomato plant defense against B. cinerea, in which treatment B. cinerea actin expression were reduced 60%. Using virus-induced gene silencing (VIGS) techniques, as compared with TRV:0 control plants, TRV:PLD3 showed more susceptible to B. cinerea, while the defense against B. cinerea were increased in TRV:FAAH1, TRV:FAAH11 tomato plants. The results show that N-Acylethanolamines metabolism are important for tomato defense against B. cinerea diseases, and the key genes PLD3, FAAH1 and FAAH11 play different roles in the tomato plants-B. cinerea interaction.-2. The mechanism of N-Acylethanolamines-involved defense against B. cinerea infection were studied. Based on the study that N-Acylethanolamines metabolism play a role in tomato plants defense against B. cinerea. Then we went further to study the underlying mechanism of N-Acylethanolamines-involved defense response. The relative gene expression analysis showed that PR1, NPR1 and PI1 can be induced after B. cinerea infection, but they were reduced under NAE18:2 treament. By contrast, the expression of ETH signaling related genes were sharply up-regulated after B. cinerea infection and NAE18:2 treamnet. Compared to the control, the contents of SA, JA, IAA and ETH were enhanced significantly after B. cinerea infection in the leaves, only the contents of ETH but not that of SA, JA, IAA were further increase by NAE18:2 treament. Using VIGS system and mutant paints, we found that exogenous NAE18:2 and ETH could significantly reduce the susceptibility to B. cinerea in TRV:PLD3 tomato plants, while exogenous NAE18:2 can not improve the defense against B. cinerea in the ETH signaling mutant nr tomato plant. These results suggest that N-Acylethanolamines-induced defense aganist B. cinerea is dependent on ETH signaling pathway.3. The effects of N-decanoyl-homoserine lactone-induced systemic resistance after B. cinerea infection were studied. N-Acylethanolamines analogue (N-decanoyl-homoserine lactone) were produced by Gram negative bacteria, which have been shown to induce diverse reactions in animals and plants. But it remains largely unknown whether DHL could induce systemic resistance to B. cinerea infection. Our results showed that tomato leaves were less susceptible to B. cinerea when DHL were treated on the roots. And the similar systemic resistance in tomato leaves can also be induced when DHL were treated on a single leaf position. When DHL were treated on the roots, the relative gene expression of PI1 and PI2 as well as the JA contant on tomato leaves were highly induced. Furthermore, DHL treament can’t increase the defense against B. cinerea in JA biosynthetic mutant plants (spr2). These results suggst that JA signaling were involved in DHL-induced systemic resistance against B. cinerea infection.