Although thaumatin-like proteins (TLPs) are involved in resistance to a variety of fungal diseases, whether the TLP5 and TLP6 genes in tomato plants (Solanum lycopersicum) confer resistance to the pathogenesis of soil-borne diseases has not been demonstrated. In this study, five soil-borne diseases (fungal pathogens: Fusarium solani, Fusarium oxysporum, and Verticillium dahliae; bacterial pathogens: Clavibacter michiganense subsp. michiganense and Ralstonia solanacearum) were used to infect susceptible “No. 5” and disease-resistant “S-55” tomato cultivars. We found that SlTLP5 and SlTLP6 transcript levels were higher in susceptible cultivars treated with the three fungal pathogens than in those treated with the two bacterial pathogens and that transcript levels varied depending on the pathogen. Moreover, the SlTLP5 and SlTLP6 transcript levels were much higher in disease-resistant cultivars than in disease-susceptible cultivars, and the SlTLP5 and SlTLP6 transcript levels were higher in cultivars treated with the same fungal pathogen than in those treated with bacterial pathogens. SlTLP6 transcript levels were higher than SlTLP5. SlTLP5 and SlTLP6 overexpression and gene-edited transgenic mutants were generated in both susceptible and resistant cultivars. Overexpression and knockout increased and decreased resistance to the five diseases, respectively. Transgenic plants overexpressing SlTLP5 and SlTLP6 inhibited the activities of peroxidase (POD), superoxide dismutase (SOD), ascorbate peroxidase (APX), and catalase (CAT) after inoculation with fungal pathogens, and the activities of POD, SOD, and APX were similar to those of fungi after infection with bacterial pathogens. The activities of CAT were increased, and the activity of β-1,3-glucanase was increased in both the fungal and bacterial treatments. Overexpressed plants were more resistant than the control plants. After SlTLP5 and SlTLP6 knockout plants were inoculated, POD, SOD, and APX had no significant changes, but CAT activity increased and decreased significantly after the fungal and bacterial treatments, contrary to overexpression. The activity of β-1,3-glucanase decreased in the treatment of the five pathogens, and the knocked-out plants were more susceptible to disease than the control. In summary, this study contributes to the further understanding of TLP disease resistance mechanisms in tomato plants.

Capsicum (Solanaceae) is a globally important vegetable crop and is also used therapeutically in traditional medicine systems. However, little is known of the genetic variation within the commonly grown cultivars, the evolutionary relationships and differences in the chloroplast (cp.) genomes between Capsicum species remain unclear. The cp. genomes of 32 Capsicum varieties in three species from 6 countries were investigated. The cp. genome of Capsicum was found to be ~ 156 kb in length and to contain 113 unique genes, of which 79 encoded proteins, 30 encoded transfer tRNAs, and 4 were for ribosomal RNAs. The 32 varieties that we chose for study represented 13 genotypes, containing a total of 608 indels, 83 SNPs, 47 SSRs and 281–306 repeat sequences. We then included several previously sequenced Capsicum cp. genomes, and found that the nine investigated species showed a number of differences in the characteristics of the four IR boundaries, and it was the non-coding regions that contained the most variable regions. We conducted a phylogenetic reconstruction using the cp. genomes of 43 representative species of Solanaceae, and the resulting phylogeny generally reflected the currently accepted classification, with the species of the pungent group having close relationship with one another. This study provides a comprehensive analysis of Capsicum chloroplast genomes, revealing significant variations in IR boundaries and other genomic features. These findings enhance our understanding of Capsicum evolution and genetic diversity.