Transcriptome analysis of root-knot nematode (Meloidogyne incognita)-resistant and susceptible sweetpotato cultivars

Abstract

Transcriptome analysis was performed on the roots of susceptible and resistant sweetpotato cultivars infected with the major root-knot nematode species Meloidogyne incognita. In addition, we identified a transcription factor-mediated defense signaling pathway that might function in sweetpotato-nematode interactions. Root-knot nematodes (RKNs, Meloidogyne spp.) are important sedentary endoparasites of many agricultural crop plants that significantly reduce production in field-grown sweetpotato. To date, no studies involving gene expression profiling in sweetpotato during RKN infection have been reported. Therefore, in the present study, transcriptome analysis was performed on the roots of susceptible (cv. Yulmi) and resistant (cv. Juhwangmi) sweetpotato cultivars infected with the widespread, major RKN species Meloidogyne incognita. Using the Illumina HiSeq 2000 platform, we generated 455,295,628 pair-end reads from the fibrous roots of both cultivars, which were assembled into 74,733 transcripts. A number of common and unique genes were differentially expressed in susceptible vs. resistant cultivars as a result of RKN infection. We assigned the differentially expressed genes into gene ontology categories and used MapMan annotation to predict their functional roles and associated biological processes. The candidate genes including hormonal signaling-related transcription factors and pathogenesis-related genes that could contribute to protection against RKN infection in sweetpotato roots were identified and sweetpotato-nematode interactions involved in resistance are discussed.

The Defense Response Involved in Sweetpotato Resistance to Root-Knot Nematode Meloidogyne incognita: Comparison of Root Transcriptomes of Resistant and Susceptible Sweetpotato Cultivars With Respect to Induced and Constitutive Defense Responses

“…However, the molecular mechanisms of nematode resistance in sweetpotato are poorly understood. Although multiple resistance genes involved in qualitative response to nematode infection have been discovered in sweetpotato through transcriptome, proteome and transgenic analyses, the exact function and mode of action of these genes remain unknown ( Fan et al, 2015 ; Zhai et al, 2016 ; Ha et al, 2017 ; Lee et al, 2019 ). Here, we performed a comprehensive analysis of gene expression in three RCs and three SCs of sweetpotato before and after infection with M. incognita infection to characterize induced and constitutive defense responses.…”

“…Previously, we reported the proteome and transcriptome profiling of two sweetpotato cultivars, namely JHM and YM, at different temporal points after infection with the RKN M. incognita ( Ha et al, 2017 ; Lee et al, 2019 ). The results showed that JHM was more resistant to RKN infection than YM when plants were cultivated for 50 days in a growth chamber and 90 days under greenhouse conditions.…”

“…Of these 64 protein spots, 20 were identified as belonging to widely different functional categories, such as the defense response, cell structure, and energy metabolism. In a transcriptomic study of 90-day cultivated sweetpotato, 74,733 transcripts were assembled and a number of unique genes were found to be differentially expressed upon RKN infection ( Lee et al, 2019 ). DEGs encoding transcription factors involved in various hormonal signaling-related pathways were identified as being associated with RKN infection.…”

“…Sweetpotato cultivars show differences in their susceptibility and resistance to RKNs, which can be exploited to reveal the genes and mechanisms responsible for resistance to RKN. We previously conducted proteome and transcriptome profiling of two sweetpotato cultivars, Yulmi and Juhwangmi, with contrasting responses to infection with M. incognita ( Ha et al, 2017 ; Lee et al, 2019 ). Recently, we identified and studied the responses of candidate genes to RKN infection in these two cultivars ( Sung et al, 2019 ; Lee et al, 2020 ).…”

Plant defense responses in monocotyledonous and dicotyledonous host plants during root-knot nematode infection

“…Another genome-wide transcriptome analysis with susceptible and resistant varieties was performed in sweet potato (Ipomoea batatas) infected with M. incognita. The authors indicated an increase in the activity of genes involved in defense signaling, including genes encoding transcription factors as well as these associated with JA, SA, ET and ABA pathways, which were upregulated in a resistant variety under RKN treatment (Lee et al 2019).…”