Response of bitter and sweet Chenopodium quinoa varieties to cucumber mosaic virus: Transcriptome and small RNASeq perspective

Abstract

Saponins are secondary metabolites with antiviral properties. Low saponin (sweet) varieties of quinoa (Chenopodium quinoa) have been developed because seeds high in saponins taste bitter. The aim of this study was to elucidate the role of saponin in resistance of quinoa to Cucumber mosaic virus (CMV). Differential gene expression was studied in time-series study of CMV infection. High-throughput transcriptome sequence data were obtained from 36 samples (3 varieties × +/- CMV × 1 or 4 days after inoculation × 3 replicates). Translation, lipid, nitrogen, amino acid metabolism, and mono- and sesquiterpenoid biosynthesis genes were upregulated in CMV infections. In ‘Red Head’ (bitter), CMV-induced systemic symptoms were concurrent with downregulation of a key saponin biosynthesis gene, TSARL1, four days after inoculation. In local lesion responses (sweet and semi-sweet), TSARL1 levels remained up-regulated. Known microRNAs (miRNA) (81) from 11 miR families and 876 predicted novel miRNAs were identified. Differentially expressed miRNA and short interfering RNA clusters (24nt) induced by CMV infection are predicted to target genomic and intergenic regions enriched in repetitive elements. This is the first report of integrated RNASeq and sRNASeq data in quinoa-virus interactions and provides comprehensive understanding of involved genes, non-coding regions, and biological pathways in virus resistance.

Reaction of three potato cultivars to potato virus S and alteration of miRNAs and mRNA targets in the resistant genotypes

“…Previous studies in different plant-virus pathosystems showed differentially expressed miRNAs associated with virus infection among or within the resistant, tolerant and susceptible genotypes (Tables S5, S6 and S7). This included the plant-virus interactions barley-barley yellow dwarf virus (BYDV) (Jarošová et al, 2020), blackgram-and soybean-mungbean yellow mosaic India virus (MYMIV) (Kundu et al, 2017;Ramesh et al, 2017), cassava-South African cassava mosaic virus (SACMV) (Bizabani et al, 2021), Chenopodium quinoa-cucumber mosaic virus (CMV) (Soltani et al, 2021), grapevine-Badnavirus (Singh et al, 2012), grapevinegrapevine leafroll-associated virus 3 (GLRaV-3) (Bester et al, 2017) and tomato-tomato leaf curl virus (ToLCV) (Tripathi et al, 2018). It was suggested that the tolerance observed in the cassava landrace TME3 might be related to a lower percentage of miRNA targets altered by SACMV and a degree of stabilization of metabolic functions (Bizabani et al, 2021).…”

“…The defensive pathways of CMV‐resistant C . quinoa 'Jessie' were induced at the early stage of infection and then suppressed at the late stage of infection, whereas the susceptible cultivar Red Head had a consistently induced defence response (Soltani et al, 2021).…”

Profile of quinoa consumption and consumers’ perception of its nutritional and functional value

“…Thus, quinoa can be considered a strategic culture with the potential to contribute to food security and sovereignty due to its nutritional quality, its wide genetic variability and tolerance regarding drought and salinity (Lim et al, 2020;Bojanic, 2011;Joshi et al, 2019). Quinoa varieties can be classified as bitter or sweet depending upon the saponin content presented in the seeds (Soltani et al, 2021). Saponins are secondary metabolites that give a bitter taste to seeds.…”

“…Saponins are secondary metabolites that give a bitter taste to seeds. For this reason, varieties with low saponin content called sweet quinoa have been preferentially developed for human consumption (Soltani et al, 2021).…”

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“…Their study found that a large number of miRNAs were differentially expressed in the two soybean NILs, that targeted a series of NBS-LRR resistance (R) genes. In a similar study by Soltani et al (2021), the effect of CMV infection on different quinoa varieties, resulted in identification of differentially expressed miRNAs and the corresponding genes that modulated the variety-specific biological pathways, such as plant-pathogen interaction (PPI), DNA replication, repair and recombination, and hormone signaling. These biological pathways ultimately result in modulation of defense hormones such as SA, JA, and ET (Soltani et al, 2020).…”