Plant Molecular Biology 1031: 1031–1039, 2002. © 2002 Kluwer Academic Publishers. Printed in the Netherlands. 1031 14-3-3 proteins and the response to abiotic and biotic stress Michael R. Roberts 1,∗ , Julio Salinas 2 and David B. Collinge 3 1 Department of Biological Sciences, IENS, Lancaster University, Lancaster LA1 4YQ, UK ( ∗ author for correspon- dence; e-mail m.r.roberts@lancaster.ac.uk); 2 Departamento de Biotecnolog ´ ia, Instituto Nacional de Investigaci´ on y Tecnolog ´ ia Agraria y Alimentaria (INIA), Carretera de la Coruña, Km. 7, 28040 Madrid, Spain; 3 Section for Plant Pathology, Department of Plant Biology, Royal Veterinary and Agricultural University, Thorvaldsensvej 40, 1871 Frederiksberg C, Copenhagen, Denmark Received 6 September 2001; accepted in revised form 7 June 2002 Key words: 14-3-3 protein, abiotic stress, biotic stress, defence responses, plant pathogen, signalling Abstract 14-3-3 proteins function as regulators of a wide range of target proteins in all eukaryotes by effecting direct protein-protein interactions. Primarily, interactions between 14-3-3 proteins and their targets are mediated by phosphorylation at specific sites on the target protein. Hence, interactions with 14-3-3s are subject to environmental control through signalling pathways which impact on 14-3-3 binding sites. Because 14-3-3 proteins regulate the activities of many proteins involved in signal transduction, there are multiple levels at which 14-3-3 proteins may play roles in stress responses in higher plants. In this article, we review evidence which implicates 14- 3-3 proteins in responses to environmental, metabolic and nutritional stresses, as well as in defence responses to wounding and pathogen attack. This evidence includes stress-inducible changes in 14-3-3 gene expression, interactions between 14-3-3 proteins and signalling proteins and interactions between 14-3-3 proteins and proteins with defensive functions. Abbreviations: ABA, abscisic acid; CDPK, calcium-dependent protein kinase/calmodulin domain protein kinase; FC, fusicoccin; H + -ATPase, plasma membrane proton pumping ATPase; HR, hypersensitive response; NR, nitrate reductase Introduction Plants growing in nature constantly sense their en- vironment and adapt to changes by using a range of biochemical and molecular mechanisms. They ex- hibit both long-term responses to the physical en- vironment in the form of modified growth patterns and metabolism, and short-term defence responses to counter immediate threats such as pathogen attack. In each case, the appropriate response is the result of the perception of external information and the relay- ing of this information between and within plant cells. The molecular and genetic basis for stress response signalling in plants has been the subject of intensive research over the past decade or so, with major areas for focus including responses to light, temperature, water and salt stress, atmospheric pollutants such as ozone, wounding, herbivory and pathogen infection. Recent reviews of these areas can be found in Bray (1997), de Bruxelles and Roberts (2001), Collinge et al. (2001), Dangl and Jones (2001), Hasegawa et al. (2000), Mackerness (2000), Mullineaux et al. (2000), Srivastava (1999) and Thomashow (1999). Intriguingly, though these stresses tend to elicit a specific final response, many of the signalling inter- mediates, such as plant hormones, reactive oxygen species, calcium, etc., are common to many path- ways. In fact this is not entirely surprising, since the plant must integrate its response to a particular stress within the context of other environmental pressures.