Enhancing tomato resistance by exploring early defense events against Fusarium wilt disease

Abstract

Studying plant early immunity, such as the unique immune mechanisms against pathogens, is an important field of research. Tomato wilt resulting from the infection by Fusarium oxysporum f. sp. lycopersici (Fol) is an important soil-borne vascular disease. In this study, we challenged tomato plants with Fol for a time-course RNA sequencing (RNA-seq) analysis. The result indicated that phenylpropanoid and flavonoid pathway genes were significantly enriched during the early invasion stage. Further study revealed that the flavonoids galangin and quercetin could effectively inhibit Fol growth and enhance wilt resistance in tomato. Moreover, the genes involved in plant-pathogen interactions, the MAPK signaling pathway, and plant hormone signal transduction were significantly enriched. These genes were also involved in plant pattern-triggered immunity (PTI) and effector-triggered immunity (ETI) signaling pathways. Strikingly, the transcription levels of pathogen-related protein 1 (SlPR1) were dramatically increased at 2 days post Fol inoculation, implying that SlPR1 is important in early immunity in tomato. SlPR1 does not have direct antifungal activity. Instead, its C-terminal peptide CAPE1 could activate root defense responses, such as the reactive oxygen species (ROS) burst, salicylic acid (SA)/jasmonic acid (JA) production, and defense-related gene expression, which collectively increased tomato resistance to Fol infection. In addition, CAPE1 could induce systemic acquired resistance (SAR). Application of CAPE1 onto tomato leaves induced local resistance to the pathogen Botrytis cinerea and systemic resistance to Fol infection. These results advanced our understanding for the early immunity against Fol in tomato and provide potential strategy for tomato disease control.

Biological Control of a Root-Knot Nematode Meloidogyne incognita Infection of Tomato (Solanum lycopersicum L.) by the Oomycete Biocontrol Agent Pythium oligandrum

“…Other tomato PR genes from the family PR1 and the PRP2 gene were up-regulated, suggesting a broad spectrum of the up-regulation of PR genes in response to P oligandrum and possibly contributing to priming tomato defenses. Recently, in tomato, a PR1 family protein called SlPR1 has been suggested to be important for early immunity against Fusarium wilt disease [53]. It is likely that the tomato's defense priming in part occurs via the constitutively expressed P. oligandrum elicitin-like protein oligandrin, as oligandrin has been shown previously to induce defense responses when applied to tomato fruit [54], and also possibly via P. oligandrum Nep1-like proteins (NLPs) which were shown recently to reduce the P. capsici infection of tomato fruits [55].…”