Expression of pathogenesis-related proteins in transplastomic tobacco plants confers resistance to filamentous pathogens under field trials

Abstract

Plants are continuously challenged by pathogens, affecting most staple crops compromising food security. They have evolved different mechanisms to counterattack pathogen infection, including the accumulation of pathogenesis-related (PR) proteins. These proteins have been implicated in active defense, and their overexpression has led to enhanced resistance in nuclear transgenic plants, although in many cases constitutive expression resulted in lesion-mimic phenotypes. We decided to evaluate plastid transformation as an alternative to overcome limitations observed for nuclear transgenic technologies. The advantages include the possibilities to express polycistronic RNAs, to obtain higher protein expression levels, and the impeded gene flow due to the maternal inheritance of the plastome. We transformed Nicotiana tabacum plastids to co-express the tobacco PR proteins AP24 and β-1,3-glucanase. Transplastomic tobacco lines were characterized and subsequently challenged with Rhizoctonia solani , Peronospora hyoscyami f.sp. tabacina and Phytophthora nicotianae . Results showed that transplastomic plants expressing AP24 and β-1,3-glucanase are resistant to R . solani in greenhouse conditions and, furthermore, they are protected against P . hyoscyami f.sp. tabacina and P . nicotianae in field conditions under high inoculum pressure. Our results suggest that plastid co- expression of PR proteins AP24 and β-1,3-glucanase resulted in enhanced resistance against filamentous pathogens.

Bacterial Isolate Inhabiting Spitsbergen Soil Modifies the Physiological Response of Phaseolus coccineus in Control Conditions and under Exogenous Application of Methyl Jasmonate and Copper Excess

“…An accumulation of PR proteins, such as GLU, is stimulated by J [37], which was mainly proved by our experiments with inoculated and non-inoculated treatments. Generally, we showed a lower GLU activity after inoculation with a non-pathogenic bacterial isolate, which is in line with the finding that its enhanced activity resulted in intensified resistance against pathogens [51].…”

Overexpression of a plasma membrane protein generated broad‐spectrum immunity in soybean

“…Overexpression of GmDR1 transgenes induced constitutive overexpression of GmPR1‐1 ( Glyma.15g062500 ), but not GmPR1‐2 ( Glyma.13G251600 ), in roots of transgenic lines (Figure 2e,f). Earlier studies have showed that overexpression of PR1 enhances resistance against both bacterial and fungal pathogens (Alexander et al ., 1993; Breen et al ., 2017; Sarowar et al ., 2005; Shin et al ., 2014) suggesting the role of antimicrobial activities of the PR1 proteins in plant defences (Boccardo et al ., 2019; Chen et al ., 2014; Leah et al ., 1991; Selitrennikoff, 2001). It is also known that PR1 proteins interact with pathogen effectors (Breen et al ., 2017; Breen et al ., 2016; Lu et al ., 2014).…”

Razor: annotation of signal peptides from toxins

“…Many toxins and defensive proteins are commercially important. For example, plant toxins such as defensin-like protein, animal toxins such as cecropin are used to develop disease-resistant transgenic crops (Stotz et al ., 2009; Lacerda et al ., 2014; Wu et al ., 2016; Pathogenesis-related proteins and peptides as promising tools for engineering plants with multiple stress tolerance, 2018; Boccardo et al ., 2019). Similarly, the cytotoxic activity of phospholipase A2 on cancer cells makes it a promising candidate for cancer therapy (Xiao et al ., 2017; Hiu and Yap, 2020; Lomonte and Rangel, 2012).…”