Systemic acquired resistance (SAR) is an inducible defence mechanism which plays a central role in protecting plants from microbial pathogen attack. Guided by bioassays, a new chemical inducer of SAR was isolated from the extracts of Strobilanthes cusia and identified to be 3-acetonyl-3-hydroxyoxindole (AHO), a derivative of isatin. Tobacco plants treated with AHO exhibited enhanced resistance to tobacco mosaic virus (TMV) and to the fungal pathogen Erysiphe cichoracearum (powdery mildew), accompanied by increased levels of pathogenesis-related gene 1 (PR-1) expression, salicylic acid (SA) accumulation and phenylalanine ammonia-lyase activity. To study the mode of action of AHO, its ability to induce PR-1 expression and TMV resistance in nahG transgenic plants expressing salicylate hydroxylase, which prevents the accumulation of SA, was analysed. AHO treatment did not induce TMV resistance or PR-1 expression in nahG transgenic plants, suggesting that AHO acts upstream of SA in the SAR signalling pathway. In addition, using two-dimensional gel electrophoresis combined with mass spectrometry, five AHO-induced plant proteins were identified which were homologous to the effector proteins with which SA interacts. Our data suggest that AHO may represent a novel class of inducer that stimulates SA-mediated defence responses.
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http://dx.doi.org/10.1111/j.1467-7652.2008.00322.x | DOI Listing |
Int J Mol Sci
November 2024
Bari Unit, Institute for Sustainable Plant Protection, Department of Biology, Agricultural and Food Sciences, National Research Council of Italy, 70126 Bari, Italy.
The immune response in plants is regulated by several phytohormones and involves the overexpression of defense genes, including the pathogenesis-related () genes. The data reported in this paper indicate that nematodes can suppress the immune response by inhibiting the expression of defense genes. Transcripts from nine defense genes were detected by qRT-PCR in the roots of tomato plants at three and seven days post-inoculation (dpi) with living juveniles (J2s) of (root-knot nematodes, RKNs).
View Article and Find Full Text PDFSci Rep
November 2024
Department of Horticultural Sciences, Citrus Research and Education Center, University of Florida, Lake Alfred, FL, USA.
BMJ Mil Health
November 2024
Department of Orthopedic Surgery, Naval Medical Center San Diego, San Diego, California, USA.
Acta Odontol Latinoam
September 2024
Universidade Federal de Minas Gerais, Faculdade de Odontologia, Departamento de Odontopediatria, Belo Horizonte, Brasil.
The negative oral health outcomes of disadvantaged racial groups have been well-documented, as racial disparity in oral health persists over time and in different locations1. However, it is important to note that skin colour has no biological meaning, and the observed differences can be physiological expressions of social injustice such as racism. Aim: The aim of this study was to analyse the association between levels of modern racism (camouflaged prejudice and affirmation of differences) and sociodemographic characteristics of Brazilian dental students.
View Article and Find Full Text PDFBr J Nutr
September 2024
Nutrition Department, Health Sciences Center, Federal University of Piauí, Ininga, Teresina64049-550, PI, Brazil.
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