Multiple Classes of Immune-Related Proteases Associated with the Cell Death Response in Pepper Plants

Abstract

Proteases regulate a large number of biological processes in plants, such as metabolism, physiology, growth, and defense. In this study, we carried out virus-induced gene silencing assays with pepper cDNA clones to elucidate the biological roles of protease superfamilies. A total of 153 representative protease genes from pepper cDNA were selected and cloned into a Tobacco rattle virus-ligation independent cloning vector in a loss-of-function study. Silencing of 61 proteases resulted in altered phenotypes, such as the inhibition of shoot growth, abnormal leaf shape, leaf color change, and lethality. Furthermore, the silencing experiments revealed that multiple proteases play a role in cell death and immune response against avirulent and virulent pathogens. Among these 153 proteases, 34 modulated the hypersensitive cell death response caused by infection with an avirulent pathogen, and 16 proteases affected disease symptom development caused by a virulent pathogen. Specifically, we provide experimental evidence for the roles of multiple protease genes in plant development and immune defense following pathogen infection. With these results, we created a broad sketch of each protease function. This information will provide basic information for further understanding the roles of the protease superfamily in plant growth, development, and defense.

Intact salicylic acid signalling is required for potato defence against the necrotrophic fungus Alternaria solani

“…This is a homolog of the A. thaliana GAT1-like protein (AT5G38200), a glutamine amidotransferase protein, and the Capsicum annuum Ncn7004 (Bae et al 2013 ). Bae et al ( 2013 ) performed virus-induced silencing in Nicotiana benthamina and showed that when infected with an avirulent pathogen, the Ncn7004 silenced plants display delayed HR and, when infected with a virulent strain, the development of disease symptoms was delayed compared to the silencing control. It is suggested that the GAT1-like protease plays a role in developmental and pathogen-induced cell death, such as HR.…”

Phytophthora cinnamomi

“…Plant proteases play important roles in plant immunity. They are involved in pathogen detection, activation of defence responses and degradation of pathogen proteases (Bae et al, 2013;Figueiredo et al, 2014). Early recognition and proteolysis of pathogen proteins can release elicitors and induce other defence strategies.…”

The influence of α-aminophosphonic acids on the activity of aminopeptidase from barley seeds—an approach to determine the enzyme specificity

“…High levels of these enzymes have been observed in plants grown under harsh conditions, especially under osmotic stress, which is due to water shortage or too high salinity (Bartling and Weiler 1992;Desimone et al 2000;Thayer et al 1988;Matsui et al 2006;Ogiwara et al 2005;Chien et al 2002). Therefore, they may be considered as an element of ''immunological response'' of plants (Fowler et al 2009;Bae et al 2013).…”