Small RNAs in Tomato: from defence to development
type: CreativeWork
description: RNA silencing is a major regulator of gene expression in plants, controlling from development to transposable element silencing and stress responses. As part of the silencing machinery, micro (mi)RNAs orchestrate silencing of their targets, either directly or through cascades of secondary small interfering (si)RNAs. To investigate the role of RNA silencing in plant immunity, I chose to focus on the miR482/2118 family, because of its diversity and presence in many plant species since the appearance of seed plants, with most genomes containing several copies, and because its members target sequences conserved in a family of disease resistance genes known Nucleotide biding site leucine-rich repeat (NLR) genes. In this dissertation, I wanted to address the extent to which the miRNA family and its derived phasiRNAs regulate expression of defence genes as well as contribute to quantitative resistance in crops. I explore the structural differences of miR482/2118 members in Solanum lycopersicum and show that they are functionally significant and affect their target preferences. My approach was based on small RNA sequencing and degradome data to characterize targets of these miRNAs, including the recently discovered tomato TAS5 locus. I also generated transgenic tomatoes constitutively expressing target mimic RNAs that sequester different miR482/2118 members. These tomato mimic RNA lines were less susceptible than their non-transgenic precursors to pathogens Phytophthora infestans and Pseudomonas syringae. Additionally, I investigated the role of small RNAs and their effector proteins during vegetative and reproductive development in tomato. I employed transcript and small RNA sequencing and CRISPR-Cas9 techniques of gene editing to investigate the impact of these factors in gamete viability and transposable element silencing in vegetative meristems. The results presented here provide new evidence about the extent that RNA silencing contributes to the regulation of vital pro…
abstract: RNA silencing is a major regulator of gene expression in plants, controlling from development to transposable element silencing and stress responses. As part of the silencing machinery, micro (mi)RNAs orchestrate silencing of their targets, either directly or through cascades of secondary small interfering (si)RNAs. To investigate the role of RNA silencing in plant immunity, I chose to focus on the miR482/2118 family, because of its diversity and presence in many plant species since the appearance of seed plants, with most genomes containing several copies, and because its members target sequences conserved in a family of disease resistance genes known Nucleotide biding site leucine-rich repeat (NLR) genes. In this dissertation, I wanted to address the extent to which the miRNA family and its derived phasiRNAs regulate expression of defence genes as well as contribute to quantitative resistance in crops. I explore the structural differences of miR482/2118 members in Solanum lycopersicum and show that they are functionally significant and affect their target preferences. My approach was based on small RNA sequencing and degradome data to characterize targets of these miRNAs, including the recently discovered tomato TAS5 locus. I also generated transgenic tomatoes constitutively expressing target mimic RNAs that sequester different miR482/2118 members. These tomato mimic RNA lines were less susceptible than their non-transgenic precursors to pathogens Phytophthora infestans and Pseudomonas syringae. Additionally, I investigated the role of small RNAs and their effector proteins during vegetative and reproductive development in tomato. I employed transcript and small RNA sequencing and CRISPR-Cas9 techniques of gene editing to investigate the impact of these factors in gamete viability and transposable element silencing in vegetative meristems. The results presented here provide new evidence about the extent that RNA silencing contributes to the regulation of vital pro…
author: Canto Pastor, Alex
language: en
keywords: small RNA, microRNA, Solanum lycopersicum, molecular biology, plant sciences, phasiRNA, meristem, slyAGO5
license: https://www.repository.cam.ac.uk/bitstreams/f2cb7d5b-1a8f-4d1d-98d1-599fb89a5a2b/download
license: https://www.rioxx.net/licenses/all-rights-reserved/
date published: 2018-03-24
date modified: 2026-07-22T22:23:56Z
provider: Cambridge University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Cambridge

PropertyValue
property ID: DOI
value: 10.17863/CAM.20845