Jasmonate - dependent and - independent pathways mediate specific effects of solar ultraviolet B radiation on leaf phenolics and antiherbivore defense
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 o...
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| Otros Autores: | , , , |
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| Formato: | Artículo |
| Lenguaje: | Español |
| Materias: | |
| Acceso en línea: | http://ri.agro.uba.ar/files/intranet/articulo/2010Demkura.pdf LINK AL EDITOR |
| Aporte de: | Registro referencial: Solicitar el recurso aquí |
| Sumario: | 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. |
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| ISSN: | 0032-0889 |