Applied Plant Biotechnology for Improving Resistance to Biotic Stress

Palmiro Poltronieri, Yiguo Hong

• Publisher: Academic Press
• Year: 2019
• ISBN:
  9780128160312
• Topic: Technology & Engineering
• Subtopic: Agriculture
• Index: Technology & Engineering

Applied Plant Biotechnology for Improvement of Resistance to Biotic Stress applies biotechnology insights that seek to improve plant genomes, thus helping them achieve higher resistance and optimal hormone signaling to increase crop yield. The book provides an analysis of the current state-of-the-art in plant biotechnology as applied to improving resistance to biotic stress. In recent years, significant progress has been made towards understanding the interplay between plants and their hosts, particularly the role of plant immunity in regulating, attenuating or neutralizing invading pathogens. As a result, there is a great need to integrate these insights with methods from biotechnology.

• Applies biotechnology insights towards improving plant genomes, achieving higher resistance and optimizing hormone signaling to increase crop yield
• Presents the most modern techniques, investigations, diagnostic tools and assays to monitor and detect contaminating agents in crops, such as grape, tomato, coffee and stone fruit
• Provides encyclopedic coverage of genes, proteins, interaction networks and mechanisms by which plants and hosts seek survival
• Discusses the methods available to make crops resistant and tolerant to disease without decreased yield or food production
• Provides insights for policymakers into the difficulties faced by scientific researchers in the use of biotechnology intervention, transgenes and genetically modified sequences

Chapter 1

Engineering plant leucine rich repeat-receptors for enhanced pattern-triggered immunity (PTI) and effector-triggered immunity (ETI)

Palmiro Poltronieri^a; Alexandre Brutus^b; Ida Barbara Reca^a; Fedra Francocci^a; Xiaofei Cheng^c; Egidio Stigliano^{d,e a} Agrofood Department, National Research Council, Institute of Sciences of Food Productions, CNR-ISPA, Lecce, Italy
^b DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, United States
^c Northeast Agricultural University, College of Agriculture, Harbin, People’s Republic of China
^d Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
^e The Sainsbury Laboratory, Norwich, United Kingdom

Abstract

This chapter presents the cutting-edge knowledge on the immune mechanisms of plants in responding to microbial pathogens: bacteria, fungi, oomycetes and viruses.

In the wide range of mechanisms of plant immunity, several approaches to enhance or alter the resistance conferred by PTI and ETI have been tested in various laboratories, such as transfer of Quantitative disease resistance genes, to gene pyramiding for avoidance of pathogen adaptation and evolution. The chapter describes the interfamily transfer of R genes, and the effectiveness of resistance gene chimeras to enhance the immune response in plants lacking an effective response to pathogen elicitors and effectors; the engineering of chimeras between various Receptor kinases, introduction of Transcription Activator Like (TAL) effector binding sites (EBE) in the promoters of executor R genes, and the modification of protease targeted sequences in R genes acting as bait for effector proteases, to activate guard R genes in the presence of other pathogens. Furthermore, it introduces the engineering of plant promoters to induce a timely activation of resistance genes only in the presence of the pathogens, for tissue specific and time window selective response. In the future, these technologies will be applicable to control the expression of resistance genes, either receptor kinases and NLR proteins, and to respond to pathogen virulence products with plant immunity or tolerance.

Keywords

Apoplast; Chimeras; Domain swapping; Effector triggered immunity (ETI); Inter-species transfer; Nucleotide binding leucine rich repeat receptors (NLRs); PAMP triggered immunity (PTI); Pathogens; Protease sequence specific cleavage sites; Receptor-like kinases (RLKs); Resistance (R) proteins

1.1 Introduction

Higher eukaryotes like plants and vertebrates share the innate immune system, to defend themselves against microbial pathogens. The first layer of the innate immunity consists in the recognition of microbial fingerprints, called Pathogen Associated Molecular Patterns (PAMPs), by Pattern Recognition Receptors (PRRs), e.g., Receptor Kinases (RKs), Receptor-Like Kinases (RLKs) and Receptor-Like Proteins (RLPs) (Saijo et al., 2018) facing into the extracellular space. As PAMPs may also occur in nonpathogenic microorganisms, the term microbe-associated molecular pattern (MAMP) is preferably used (Boller and Felix, 2009). The non-race-specific inducers of defense were termed elicitors, in general a term that may refer also to lipids or carbohydrates or glycoproteins, and effectors, for virulence proteins coded by specific strains, under selection pressure and subjected to rapidly evolve (Boller, 1995; Bent and Mackey, 2007; Boller and Felix, 2009).

Two types of molecular patterns, MAMPs and Damage Associated Molecular Patterns (DAMPs) are sensed by PRRs. When Pattern Triggered Immunity (PTI), the first layer of defense, is not “working”, due to successful pathogens injecting special effectors into the cell to suppress PTI by manipulating and/or modifying the PTI components. Plants have evolved a second layer of immunity, termed Effector Triggered Immunity (ETI) (Chisholm et al., 2006; Jones and Dangl, 2006; Boller and Felix, 2009). ETI is triggered when the cytoplasmic Resistance proteins (R) encoded by R genes sense the effectors injected by the pathogens suppressing PTI: these recognition complexes activate downstream signals that result in plant defense (Bent and Mackey, 2007; Boller and Felix, 2009).

PTI and ETI form a very powerful innate immune system, able to protect the plants from the invasion of 99% phytopathogens from the environment. However, few phytopathogens are able to suppress both PTI and ETI to cause disease on the plants. Introduction of R genes from wild ancestors or between varieties via breeding is one of the major strategies to confer resistance against viruses and other pathogens. Along with the growing knowledge of plant immune system, researchers engineer immune receptors, e.g., plant ...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Contributors
• Introduction
• Chapter 1: Engineering plant leucine rich repeat-receptors for enhanced pattern-triggered immunity (PTI) and effector-triggered immunity (ETI)
• Chapter 2: Virus induced gene silencing for functional genomics in plants
• Chapter 3: Bringing PTI into the field
• Chapter 4: NBS-LRR genes—Plant health sentinels: Structure, roles, evolution and biotechnological applications
• Chapter 5: Informatic tools and platforms for enhancing plant R-gene discovery process
• Chapter 6: Spatial transcriptional response of plants induced by compatible pathogens and its potential use in biosensor plants
• Chapter 7: Grapevine: Resistance genes, sRNAs and immunity
• Chapter 8: Using genomics tools to understand plant resistance against pathogens: A case study of Magnaporthe-rice interactions
• Chapter 9: Microbial products and secondary metabolites in plant health
• Chapter 10: Molecular tools to investigate Sharka disease in Prunus species
• Chapter 11: Plant viruses against RNA silencing-based defenses: Strategies and solutions
• Chapter 12: Criniviruses infecting vegetable crops
• Chapter 13: Role of methylation during geminivirus infection
• Chapter 14: Foresight on nanovesicles in plant-pathogen interactions
• Chapter 15: The role of phytohormones in plant-viroid interactions
• Index