Genetic engineering for increasing fungal and bacterial disease resistance in crop plants

Abstract

We review the current and future potential of genetic engineering strategies used to make fungal and bacterial pathogen-resistant GM crops, illustrating different examples of the technologies and the potential benefits and short-falls of the strategies. There are well- established procedures for the production of transgenic plants with resistance towards these pathogens and considerable progress has been made using a range of new methodologies. There are no current commercially available transgenic plant species with increased resistance towards fungal and bacterial pathogens; only plants with increased resistance towards viruses are available. With an improved understanding of plant signaling pathways in response to a range of other pathogens, such as fungi, additional candidate genes for achieving resistance are being investigated. The potential for engineering plants for resistance against individual devastating diseases or for plants with resistance towards multiple pathogens is discussed in detail.

Increased resistance to fungal wilts in transgenic eggplant expressing alfalfa glucanase gene

“…Genetic engineering of disease resistance by transfer of plant defense-related genes into crops is valuable in terms of cost, efficacy, and reduction of pesticide usage (Lin et al 2004;Wally and Punja 2010;Ceasar and Ignacimuthu 2012). In this study, we explored the possibility of the use of a glucanase gene from alfalfa against two important fungal pathogens of eggplant, viz.…”

“…Most of the cultivated varieties are highly susceptible to diseases caused by various pathogens (fungal, bacterial, and viral pathogens) as well as other stresses, and such stresses result in significant loss of crop yield and quality (Collonnier et al 2001;Kashyap et al 2003;Wally and Punja 2010;Ceasar and Ignacimuthu 2012). Eggplant wilt caused by a number of fungal genera such as Fusarium, Verticillium, Rhizoctonia, Sclerotium, and Phytophthora cause considerable loss in crop yield annually (Najar et al 2011).…”

“…Over-expression of defense response genes in transgenic plants have provided enhanced resistance to a variety of fungal pathogens (Grover and Gowthaman 2003;Wally and Punja 2010). For instance, pathogenesis-related (PR) proteins are induced in plants in response to various pathogens.…”

“…3.2.1.39) belong to class II of the PR proteins and are abundant proteins widely distributed among the seed plant species. They are primarily involved in plant defense against pathogens as they catalyze the hydrolysis of β-1,3-glucans which is a major component of the cell wall of most fungi (Rao et al 1999;Punja 2001;Grover and Gowthaman 2003;Wally and Punja 2010;Ceasar and Ignacimuthu 2012). Enzyme activity is usually low in a healthy plant but increases during fungal infection, and the induction of β-1,3-glucanase in various plants like barley, wheat, rice, and sorghum in response to fungal pathogens clearly demonstrate the involvement of the enzyme in defense response (Cheong et al 2000;Grover and Gowthaman 2003;Płazek et al 2009;Cawood et al 2010;Aggarwal et al 2011;Salim et al 2011;Gupta et al 2013).…”

“…The expression of the glucanase gene in transgenic plants has conferred increased resistance against fungal pathogens (Rao et al 1999;Punja 2001;Maziah et al 2007;Mondal et al 2007;Wally and Punja 2010;Sundaresha et al 2010;O'Kennedy et al 2011;Ceasar and Ignacimuthu 2012). Increased resistance against Phytophthora infestans due to increase in glucanase activity in transgenic potato plants expressing soybean glucanase gene have been reported (Borkowoska et al 1998).…”