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Plant Cell Environ

Title:		Illuminated behaviour: phytochrome as a key regulator of light foraging and plant anti-herbivore defence
Author(s):		Ballare CL;
Address:		"IFEVA, Consejo Nacional de Investigaciones Cientificas y Tecnicas, and Universidad de Buenos Aires, Avenida San Martin 4453, C1417DSE Buenos Aires, Argentina. ballare@ifeva.edu.ar"
Journal Title:		Plant Cell Environ
Year:		2009
Volume:		20090209
Issue:		6
Page Number:		713 - 725
DOI:		10.1111/j.1365-3040.2009.01958.x
ISSN/ISBN:		1365-3040 (Electronic) 0140-7791 (Linking)
Abstract:		"In many ecological scenarios, the success of an individual plant is defined by the behavioural decisions that it makes when confronted with the risks of competition with other plants, and biomass losses to insect herbivores. These decisions involve expression of shade avoidance responses and induced chemical defences. Because these responses are costly, they frequently engender resource allocation dilemmas. In this review, I discuss the mechanisms that trigger adaptive responses to competitors and herbivores, highlighting the role of phytochromes as central organizers of the overall resource allocation strategy of plants. Phytochromes sense the reduction in the red to far-red (R : FR) ratio of sunlight caused by the proximity of other plants. Shade-intolerant plants respond to low R : FR ratios with shade avoidance behaviours and reduced investment in defence. Pfr depletion leads to increased stability of growth-promoting phytochrome-interacting factors (PIFs), and results in the production of auxins and gibberellins, degradation of DELLA proteins, which are repressors of PIFs, and reduced sensitivity to jasmonates. Thus, phytochrome appears to fulfil its organizational role by regulating the relative strength of the signalling circuits controlled by growth-related and defence-related hormones. I point out cases of signalling redundancy and discuss the significance of recent work on hormone signalling for our understanding of the mechanisms that control adaptive plant behaviour"
Keywords:		"*Adaptation, Physiological *Light Phytochrome/*physiology Plant Growth Regulators/physiology *Plant Physiological Phenomena Plants/metabolism/*radiation effects;"
Notes:		"MedlineBallare, Carlos L eng Research Support, Non-U.S. Gov't Review 2009/02/18 Plant Cell Environ. 2009 Jun; 32(6):713-25. doi: 10.1111/j.1365-3040.2009.01958.x. Epub 2009 Feb 9"