Inducing Fungus-Resistance into Plants through Biotechnology

Shabir Hussain WANI

doi:10.15835/nsb224594

Abstract

Plant diseases are caused by a variety of plant pathogens including fungi, and their management requires the use of techniques like transgenic technology, molecular biology, and genetics. There have been attempts to use gene technology as an alternative method to protect plants from microbial diseases, in addition to the development of novel agrochemicals and the conventional breeding of resistant cultivars. Various genes have been introduced into plants, and the enhanced resistance against fungi has been demonstrated. These include: genes that express proteins, peptides, or antimicrobial compounds that are directly toxic to pathogens or that reduce their growth in situ; gene products that directly inhibit pathogen virulence products or enhance plant structural defense genes, that directly or indirectly activate general plant defense responses; and resistance genes involved in the hypersensitive response and in the interactions with virulence factors. The introduction of the tabtoxin acetyltransferase gene, the stilbene synthase gene, the ribosome-inactivation protein gene and the glucose oxidase gene brought enhanced resistance in different plants. Genes encoding hydrolytic enzymes such as chitinase and glucanase, which can deteriorate fungal cell-wall components, are attractive candidates for this approach and are preferentially used for the production of fungal disease-resistant plants. In addition to this, RNA-mediated gene silencing is being tried as a reverse tool for gene targeting in plant diseases caused by fungal pathogens. In this review, different mechanisms of fungal disease resistance through biotechnological approaches are discussed and the recent advances in fungal disease management through transgenic approach are reviewed.

Highlights

Plant pathogens are a real threat to worldwide agriculture
A number of resistant cultivars have been developed through breeding programs, these cultivars become obsolete in a short time due to the rapid evolution of the phytopathogens and the emergence of virulent forms capable to overcome the plant resistance
Homology-based gene silencing induced by transgenes, antisense RNA, or dsRNA has been demonstrated in many plant pathogenic fungi, including Cladosporium fulvum (Hamada and Spanu, 1998), Magnaporthae oryzae (Kadotani et al, 2003), Venturia inaequalis (Fitzgerald et al, 2004), Neurospora crassa (Goldoni et al, 2004), Aspergillus nidulans (Hammond and Keller 2005), and Fusarium graminearum (Nakayashiki et al, 2005)

Summary

Introduction

Plant pathogens are a real threat to worldwide agriculture. Significant yield losses due to fungal attacks occur in most of the agricultural and horticultural species. Fungal diseases are rated either the most important or second most important factor contributing to yield losses in major crops like rice (Lee et al, 2007), wheat (Huang and Gill, 2001), barley (Smith, 2002), cotton (Cui et al, 2000), groundnut (Mace et al, 2006), and grapevine (Dhekney et al, 2007). The advances in gene engineering technologies and the understanding of the molecular nature of plant protection mechanisms have provided means for developing principally new strategies of plant disease control, in addition to the traditional approaches based on employing chemicals or classical breeding schemes. Biotechnology will enhance our understanding of the mechanisms that control plant’s ability to recognize and defend itself against disease caused by fungi (Punja, 2007). The integration of biotechnology with traditional agricultural practices will be the backbone for sustainable agriculture

Plant biotechnology and fungal disease management

Mechanism disease resistant genes on plant

Fusarium graminearum Thielaviopsis basicola Rhizoctonia solani

RNA silencing

Findings

Conclusions and future prospects