Comparative transcriptomics reveals suppressed expression of genes related to auxin and the cell cycle contributes to the resistance of cucumber against Meloidogyne incognita

Abstract

BackgroundMeloidogyne incognita is a devastating nematode that causes significant losses in cucumber production worldwide. Although numerous studies have emphasized on the susceptible response of plants after nematode infection, the exact regulation mechanism of M. incognita-resistance in cucumber remains elusive. Verification of an introgression line, ‘IL10–1’, with M. incognita-resistance provides the opportunity to unravel the resistance mechanism of cucumber against M. incognita.ResultsIn the present study, analyses of physiological responses and transcriptional events between IL10–1 (resistant line) and CC3 (susceptible line) were conducted after M. incognita infection. Physiological observations showed abnormal development of giant cells and M. incognita in IL10–1, which were the primary differences compared with CC3. Furthermore, Gene ontology (GO) analysis revealed that genes encoding cell wall proteins were up-regulated in IL10–1 and that the highly expressed lipid transfer protein gene (Csa6G410090) might be the principal regulator of this up-regulation. Simultaneously, analyses of gene expression profiles revealed more auxin-related genes were suppressed in IL10–1 than in those of CC3, which corresponded with the lower level of indole acetic acid (IAA) in the roots of IL10–1 than in those of CC3. Additionally, poor nucleus development as a clear indication of abnormal giant cells in IL10–1 was related to inhibition of the cell cycle. Of those genes related to the cell cycle, the F-box domain Skp2-like genes were down-regulated in IL10–1, whereas more of these genes were up-regulated in CC3.ConclusionsAll of these findings indicate that suppressed expression of genes related to auxin and the cell cycle and highly expressed cell wall proteins play important roles in the abnormal development of giant cells, which hinders the development of M. incognita, thereby causing resistance to M. incognita in IL10–1. Knowledge from this research will provide a useful foundation for developing effective strategies in M. incognita-resistance breeding.Electronic supplementary materialThe online version of this article (10.1186/s12864-018-4979-0) contains supplementary material, which is available to authorized users.

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

“…And RNA-seq was used to verify the transcriptomic profiles of LA3858 in response to M. incognita, and the reliability of the RNA-seq data was verified by the significant positive correlation detected between the qRT-PCR data and the RNA-seq data (Additional file 5). GO analysis revealed that most of the DEGs were enriched in the "cell wall", "external encapsulating structure", "cell division" and other key terms at 3 dpi between 34°C and 25°C, which may be related to GC formation [17]. DEGs were significantly enriched in each of the identified KEGG pathways, which were shown to be associated with plant immunity in a previous study.…”

Identification and Expression Analysis of the CsMYB Gene Family in Root Knot Nematode-Resistant and Susceptible Cucumbers

“… Expression profile of CsMYB genes through time after infection with M. incognita in resistant and susceptible cucumber lines, IL10-1 and CC3. Expression profile of CsMYB genes in response to the inoculation of M. incognita on published data RNA-seq SRP125669 ( Wang et al, 2018 ). The color scale represents relative gene expression levels.…”

“…In this study, the expression data for all 112 CsMYB genes in the two lines, IL10-1 and CC3, contrasting for RKN resistance were obtained directly from NCBI by SRP125669 ( Wang et al, 2018 ) at 0, 1, 2 and 3 days after inoculation (dpi) with M . incognita .…”

“…In order to study changes in gene expression correlated with expression of resistance to Meloidogyne incognita in cucumber, gene expression in a RKN-resistant line, IL10-1, and RKN-susceptible line, “Beijingjietou” (CC3), that display marked differences in against M . incognita ( Ye et al, 2011 ), were obtained directly from NCBI by SRP125669 ( Wang et al, 2018 ) at 0, 1, 2 and 3 days after inoculation (dpi) with approximately 50 fresh and motile second-stage juveniles (J2) M. incognita . The readings per kilobyte million enzyme (RPKM) for each MYB gene were downloaded and calculated from NCBI 9 .…”

“…Although new insights regarding the mechanisms by which MYB proteins control various plant processes and several core genes have been identified, the TFs in question are usually encoded by very large multigene families confounding detailed mechanistic studies, consistent with the likelihood that many of the complex regulatory roles played by MYB genes-encoding-proteins remain unknown ( Riechmann et al, 2000 ). Our previous comparative transcriptomic study showed that MYB TFs may participate in regulating the hub gene LTP (lipid transfer protein) of cucumber in resistance to root-knot nematode (RKN) [ Meloidogyne incognita Kofoid and White (Chitwood)] ( Wang et al, 2018 ). LTP, a member of plant pathogenesis-related protein (PRs), is involved in lipid transport in giant cells (GCs) membranes and receives signals stimulated by exposure to nematodes ( Wang X. et al, 2020 ).…”