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Plant Physiol

Title:		Jasmonate-dependent and -independent pathways mediate specific effects of solar ultraviolet B radiation on leaf phenolics and antiherbivore defense
Author(s):		Demkura PV; Abdala G; Baldwin IT; Ballare CL;
Address:		"Instituto de Investigaciones Fisiologicas y Ecologicas vinculadas a Agricultura, Consejo Nacional de Investigaciones Cientificas y Tecnicas-Universidad de Buenos Aires, C1417DSE Buenos Aires, Argentina"
Journal Title:		Plant Physiol
Year:		2010
Volume:		20091209
Issue:		2
Page Number:		1084 - 1095
DOI:		10.1104/pp.109.148999
ISSN/ISBN:		1532-2548 (Electronic) 0032-0889 (Print) 0032-0889 (Linking)
Abstract:		"Ultraviolet B (UV-B) radiation, a very small fraction of the daylight spectrum, elicits changes in plant secondary metabolism that have large effects on plant-insect interactions. The signal transduction pathways that mediate these specific effects of solar UV-B are not known. We examined the role of jasmonate signaling by measuring responses to UV-B in wild-type and transgenic jasmonate-deficient Nicotiana attenuata plants in which a lipoxygenase gene (NaLOX3) was silenced (as-lox). In wild-type plants, UV-B failed to elicit the accumulation of jasmonic acid (JA) or the bioactive JA-isoleucine conjugate but amplified the response of jasmonate-inducible genes, such as trypsin proteinase inhibitor (TPI), to wounding and methyl jasmonate, and increased the accumulation of several phenylpropanoid derivatives. Some of these phenolic responses (accumulation of caffeoyl-polyamine conjugates) were completely lacking in as-lox plants, whereas others (accumulation of rutin and chlorogenic acid) were similar in both genotypes. In open field conditions, as-lox plants received more insect damage than wild-type plants, as expected, but the dramatic increase in resistance to herbivory elicited by UV-B exposure, which was highly significant in wild-type plants, did not occur in as-lox plants. We conclude that solar UV-B (1) uses jasmonate-dependent and -independent pathways in the elicitation of phenolic compounds, and (2) increases sensitivity to jasmonates, leading to enhanced expression of wound-response genes (TPI). The lack of UV-B-induced antiherbivore protection in as-lox plants suggests that jasmonate signaling plays a central role in the mechanisms by which solar UV-B increases resistance to insect herbivores in the field"
Keywords:		"Acetates/pharmacology Animals Cyclopentanes/*metabolism/pharmacology Gene Silencing Insecta Oxylipins/*metabolism/pharmacology Phenols/*metabolism Plant Leaves/genetics/metabolism/*radiation effects Plants, Genetically Modified/genetics/metabolism/radiati;"
Notes:		"MedlineDemkura, Patricia V Abdala, Guillermina Baldwin, Ian T Ballare, Carlos L eng Research Support, Non-U.S. Gov't 2009/12/17 Plant Physiol. 2010 Feb; 152(2):1084-95. doi: 10.1104/pp.109.148999. Epub 2009 Dec 9"