Overexpression of a typical aspartic protease (At1g11910) confers to Arabidopsis thaliana resistance to Botrytis cinerea infection.

BERLI, ANABELA; TONON, C.V.; FERNANDO, FIOL DIEGO; MARÍA G. GUEVARA.

Mendoza

Congreso; Congreso SAIB; 2022

Aspartic proteases (APs) are a family of proteolytic enzymes widely distributed among living organisms. Plant APs are involved in various biological processes as in the plant defense mechanism to abiotic and biotic stresses. In our laboratory we identified, purified, characterized, and cloned two typical APs from Solanum tuberosum (StAP1 and StAP3). These typical APs are bifunctional enzymes, with antimicrobial and proteolytic activities, and their expression is directly correlated with the resistance of potato plants to P. infestans infection. We detected three StAP1 homologous genes in A. thaliana. These genes are At1g11910 (80% id) (named as APA1), At1g62290 (82% id) and At4g04460 (83% id). According to data described in the Arabidopsis eFP browser APA1 gene is induced in leaves after Botrytis cinerea infection. However, there are no data that correlate the induction of this gene with the increase or decrease of the defense response of A. thaliana to B. cinerea infection. The current study aimed to evaluate this correlation and the potential role of APA1 in the mechanism of the response of A. thaliana plants to B. cinerea infection. Obtained results show that the foliar area affected by B. cinerea infection was larger in mutant plants (apa1) than the observed in wild type (WT) and OE- AP1 plants. This result indicates that the APA1 gene is involved in the defense response mechanism of A. thaliana plants to B. cinerea infection and, that overexpression of the APA1 gene increases the resistance of plants to B. cinerea. Data obtained from real-time PCR assays show that overexpression of APA1 induces the expression of genes that regulate the jasmonic acid signaling pathway, like PDF1.2, in response to necrotrophic pathogen infection. In apa1 plants expression levels of the PDF1.2 gene were lower than the PDF1.2 expression levels determined in WT and OE- APA1 plants, at all times analyzed. On the other hand, and according to data described for other antimicrobial peptides and the plant-specific insert (PSI) overexpressed in A. thaliana, OE- APA1 plants showed increased PR-2 expression levels upon B. cinerea infection compared to apa1 and WT plants. The results obtained show that this typical AP (APA1) is involved in the defense mechanism of A. thaliana and that its overexpression confers significant enhancement in the defense response against B. cinerea infection. We propose the development of crops with increased levels of APA1 as a strategy to improve the resistant to pathogens and thereby minimize the use of agrochemicals