Transcriptomic profiling of Solanum peruvianum LA3858 revealed a Mi-3-mediated hypersensitive response to Meloidogyne incognita

Abstract

Background: The Mi-1 gene was the first identified and cloned gene that provides resistance to root-knot nematodes (RKNs) in cultivated tomato. However, owing to its temperature sensitivity, this gene does not meet the need for breeding disease-resistant plants that grow under high temperature. In this study, Mi-3 was isolated from the wild species PI 126443 (LA3858) and was shown to display heat-stable resistance to RKNs. However, the mechanism that regulates this resistance remains unknown. Results: In this study, 4760, 1024 and 137 differentially expressed genes (DEGs) were enriched on the basis of pairwise comparisons (34°C vs. 25°C) at 0 (before inoculation), 3 and 6 days post-inoculation (dpi), respectively. A total of 7035 DEGs were identified from line LA3858 in the respective groups under the different soil temperature treatments. At 3 dpi, most DEGs were enriched in Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways related to plant biotic responses, such as "plant-pathogen interaction" and "plant hormone signal transduction". Significantly enriched DEGs were found to encode key proteins such as R proteins and heat-shock proteins (HSPs). Moreover, other DEGs were found to participate in Ca 2+ signal transduction; the production of ROS; DEGs encoding transcription factors (TFs) from the bHLH, TGA, ERF, heat-shock transcription factor (HSF) and WRKY families were highly expressed, which contribute to be involved into the formation of phytohormones, such as salicylic acid (SA), jasmonic acid (JA) and ethylene (ET), the expression of most was upregulated at 3 dpi at the 25°C soil temperature compared with the 34°C soil temperature.

Transcriptomic Analysis of Resistant and Susceptible Responses in a New Model Root-Knot Nematode Infection System Using Solanum torvum and Meloidogyne arenaria

“…1,029 genes were upregulated, and 180 genes were down-regulated at at least onetime point in both A2-J and A2-O infected plants (Figure 2B). Previous studies showed that the expression of genes associated with the salicylic acid (SA), jasmonic acid (JA), and ethylene (ET) signaling pathways are induced in resistant plants infected with PPNs (Ye et al, 2017;Zhang H. et al, 2017;Bali et al, 2019;Du et al, 2020;Ghaemi et al, 2020), so we investigated the expression of marker genes for hormone biosynthesis, hormone signaling (Figure 2C), and defense responses (Figure 2D). Infection with A2-O significantly induced the expression of SA-regulated genes that encode basic pathogenesis-related protein 1 (PR1) and β-1,3glucanase (PR2), as well as a JA biosynthesis gene (lipoxygenase D (LoxD)), the JA-regulated gene protease inhibitor II (PI-II), and two ET biosynthesis genes (1-aminocyclopropane-1-carboxylate synthase (ACS) and 1-aminocyclopropane-1-carboxylate oxidase (ACO)) (Farmer et al, 1992;Yan et al, 2013;Booker and DeLong, 2015;Zhang et al, 2018;Marhavý et al, 2019;Figure 2C).…”

The role of endophyte M7SB41 ( Seimatosporium sp.) from wild Rosa in enhancing host plant’s powdery mildew resistance

“…WRKY41 is likely to be a key regulator in the cross talk of SA and JA pathways. WRKY41-overexpressing Arabidopsis exhibited constitutive expression of the PR5 gene, but partially suppresses the JA-mediated signaling pathway (Du et al, 2020;Higashi et al, 2008). Contrary to this, it was found that WRKY 40 genes (XM 016621642.1, XM 016651389.1) were down-regulated in E+ plants at 0h (Table S4).…”

“…After Ca 2+ signals are instantaneously activated, the expression of downstream TFs such as WRKY TFs may be regulated (Du et al, 2020). CDPKs may target WRKY TFs, and then affect defense hormones locally or systemically in response to pathogen infection (Wang et al, 2016).…”

“…The result showed that the endophyte M7SB 41 (Seimatosporium sp.) from PM resistant variety significantly enhanced host plants PM resistance (Zhao et al, 2020). However, the mechanisms employed by the endophyte in PM control are still unclear.…”

Pattern‐triggered immunity against root‐knot nematode infection: A minireview

“…Another heat‐stable R locus, Mi‐3 , was identified in Solanum peruvianum , though multiple factors have prevented the gene from being cloned (Yaghoobi et al, 2005). RNAseq of Mi‐3 ‐containing tomatoes after M. incognita infection indicated a role for Mi‐3 in activating the PTI response (Du et al, 2020). The gene encoding FLS2 (FLAGELLIN‐SENSING 2), the PRR that recognizes the bacterial PAMP flg22, was upregulated at 3 days post‐inoculation (dpi).…”