Differential mRNA Accumulation upon Early Arabidopsis thaliana Infection with ORMV and TMV-Cg Is Associated with Distinct Endogenous Small RNAs Level

Abstract

Small RNAs (sRNAs) play important roles in plant development and host-pathogen interactions. Several studies have highlighted the relationship between viral infections, endogenous sRNA accumulation and transcriptional changes associated with symptoms. However, few studies have described a global analysis of endogenous sRNAs by comparing related viruses at early stages of infection, especially before viral accumulation reaches systemic tissues. An sRNA high-throughput sequencing of Arabidopsis thaliana leaf samples infected either with Oilseed rape mosaic virus (ORMV) or crucifer-infecting Tobacco mosaic virus (TMV-Cg) with slightly different symptomatology at two early stages of infection (2 and 4dpi) was performed. At early stages, both viral infections strongly alter the patterns of several types of endogenous sRNA species in distal tissues with no virus accumulation suggesting a systemic signaling process foregoing to virus spread. A correlation between sRNAs derived from protein coding genes and the associated mRNA transcripts was also detected, indicating that an unknown recursive mechanism is involved in a regulatory circuit encompassing this sRNA/mRNA equilibrium. This work represents the initial step in uncovering how differential accumulation of endogenous sRNAs contributes to explain the massive alteration of the transcriptome associated with plant-virus interactions.

Identification and characterization of microRNAs in Humulus lupulus using high-throughput sequencing and their response to Citrus bark cracking viroid (CBCVd) infection

“…This may indicate either an induction of the 21 nt class or a repression of the 24 nt class of sRNAs in response to CBCVd infection. This observation is in accordance with some previous reports showing the over accumulation of the 21-nt class of sRNAs in response to viroid and virus infection in plants [66, 67]. The different distribution patterns of 21-nt and 24-nt classes of sRNAs provided explicit evidence to support the possibility of the involvement of multiple RNA-silencing pathways and their cross interaction [68] due to CBCVd-infection.…”

RdDM pathway is required forTobamovirus-induced symptomatology production

“…In detail, the infection with ORMV and TMV-Cg produced accumulation alteration of 24-nt sRNAs in selected genes. Furthermore, in accordance with Zavallo et al 2015, we confirmed that viral infection alters the profile of sRNAs in early times of infection. Importantly, viral infection alters to greater extent 24-nt sRNAs associated with TEs (Fig.…”

“…Because 24-nt sRNAs play an important role in plant immunity through Transcriptional Gene Silencing (TGS) (Huang et al ., 2016), we first performed a comparative sRNA-seq analysis between non-infected (mock inoculated) and infected plants with two Tobamoviruses (TMV-Cg and ORMV) at 4 dpi (Zavallo et al ., 2015) to evaluate and select genes mapped by 24-nt endogenous sRNAs.…”

Arabidopsis phenotyping through geometric morphometrics

“…These symptoms vary depending on various aspects, including genetic compatibility and environmental conditions. Given a particular host-virus interaction, different viral strains trigger different symptomatology, which is more or less subtle for the observer to distinguish [38–40]. Comparing the severity of qualitative viral symptoms (i.e., the degree to which infected plants depart from healthy controls in some observable phenotype, often referred to as the aerial parts of the plant such as leaves, stems, or rosettes) is a difficult task; it is performed mainly by visually rating symptoms (e.g., [41]).…”