Increased tolerance to two oomycete pathogens in transgenic tobacco expressing pathogenesis-related protein 1a.

Abstract

Expression of pathogenesis-related protein 1a (PR-1a), a protein of unknown biochemical function, is induced to high levels in tobacco in response to pathogen infection. The induction of PR-1a expression is tightly correlated with the onset of systemic acquired resistance (SAR), a defense response effective against a variety of fungal, viral, and bacterial pathogens. While PR-1a has been postulated to be involved in SAR, and is the most highly expressed of the PR proteins, evidence for its role is lacking. In this report, we demonstrate that constitutive high-level expression of PR-1a in transgenic tobacco results in tolerance to infection by two oomycete pathogens, Peronospora tabacina and Phytophthora parasitica var. nicotianae.

Comparative Analysis of the Receptor-Like Kinase Family in Arabidopsis and Rice[W]

“…Interestingly, the ECDs in two novel rice receptors, PR-1/SCP and chitinase RLKs, are both pathogenesis-related proteins implicated in defense responses. In tobacco (Nicotiana tabacum), the expression of PR-1a is tightly correlated with the onset of systemic acquired resistance, and its overexpression results in higher tolerance to fungal pathogens (Alexander et al, 1993). Our findings indicate that new receptors were made and retained through the process of selection in these two plant lineages independently.…”

Resistance gene-dependent plant defense responses.

“…Overall, two facts have emerged from these overexpression experiments. First, the basic forms of PR proteins, which are targeted to the vacuole, exhibit more effective antifungal activity than their acidic counterparts, which are secreted from the plant cell (Sela-Buurlage et al, 1993); the only exception to date is the tobacco PR-la protein (Alexander et al, 1993). Second, when two or more PR proteins are constitutively coexpressed, a synergistic increase in the leve1 of disease control can be obtained (Zhu et al, 1994).…”

An Antifungal Protein from the Marine Bacterium Streptomyces sp. Strain AP77 Is Specific for Pythium porphyrae , a Causative Agent of Red Rot Disease in Porphyra spp

“…On the other hand, several crops which exhibit tolerance to fungal pathogens have been developed among the higher terrestrial plants by using the transgenic technique (2,9,33,35,38,40,59). Many of the resistance genes used for transformation of these plants encode polysaccharolytic enzymes, such as chitinase (8,9,23,51) and ␤-1,3-glucanase (7,23,45,51,60), which should degrade the cell walls of invading fungi.…”