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Root rot caused by Fusarium solani, is one of the most severe diseases in pepper (Capsicum annuum L.). Grafting has been attempted as an effective means to control the disease, but little is known about the disease resistance mechanism in grafted pepper. Therefore, we investigated the changes of biomass, cell structure, and the secondary metabolism in roots of control (non-grafted pepper) and grafted peppers using cvs. Weishi and Buyeding as rootstocks and the cv. Xinfeng 2 as a scion. After a manual inoculation, less F. solani invaded grafted pepper roots and consequently less serious injury to the root cell ultra-structure compared with the control was found. The roots of grafted pepper infected with F. solani exhibited greater biomass production and root activity than the roots of infected controls. Grafting led to an increased content of salicylic acid, benzoic acid, vanillin, lignin, and polyamines, as well as activities of phenylalanine ammonia lyase, polyphenoloxidase, and peroxidase. These results suggest that grafting improved the resistance of peppers to root rot.

NAC (NAM, ATAF1,2, and CUC2) transcription factors play an important role in the responses of plants to various environmental stresses. To investigate the function of SlNAC1, which was found to be a member of the ATAF subfamily in tomato (Solanum lycopersicum L.) plants under heat stress conditions, transgenic tomato plants were generated using an antisense technology. After a treatment at 40 °C for 48 h, in comparison with wild-type (WT) plants, the transgenic plants were severely wilted and exhibited a lower net photosynthetic rate and a maximal photochemical efficiency of photosystem II. Moreover, the transgenic plants displayed a higher ion leakage and malondialdehyde content and a lower proline content. The content of reactive oxygen species (superoxide anion radicals and hydrogen peroxide) were higher, and activities of ascorbate peroxidase and superoxide dismutase lower in the transgenic plants than in the WT plants. The transgenic plants also exhibited a lower accumulation of the transcripts of some heat shock protein genes (Hsp70, Hsp90, sHsp17.4, and sHsp17.6). All of these results suggest that the suppression of SlNAC1 could obviously reduce heat resistance in the tomato plants, and this indicates that SlNAC1 played an important role in the thermal tolerance of the tomato plants.