Multiple Phytochromes Are Involved in Red-Light-Induced Enhancement of First-Positive Phototropism in Arabidopsis thaliana

Janoudi, Abdul-kader; Gordon, William R.; Wagner, Doris; Quail, Peter H.; Poff, Kenneth L.

doi:10.1104/pp.113.3.975

Cited by 88 publications

(67 citation statements)

References 11 publications

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“…Both phyA and phyB have been shown to modulate phototropism in Arabidopsis (Parks etal. 1996;Janoudi & Poff 1997). First positive phototropism was found to be enhanced by phyA in response to very low-to-low fluence R (Parks et al 1996).…”

Section: Phytochrome and Phototropismmentioning

confidence: 93%

Gravity, light and plant form

Hangarter

1997

Plant Cell & Environment

179

124

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Plants have evolved highly sensitive and selective mechanisms that detect and respond to various aspects of their environment. As a plant develops, it integrates the environmental information perceived by all of its sensory systems and adapts its growth to the prevailing environmental conditions. Light is of critical importance because plants depend on it for energy and, thus, survival. The quantity, quality and direction of light are perceived by several different photosensory systems that together regulate nearly all stages of plant development, presumably in order to maintain photosynthetic efficiency. Gravity provides an almost constant stimulus that is the source of critical spatial information about its surroundings and provides important cues for orientating plant growth. Gravity plays a particularly important role during the early stages of seedling growth by stimulating a negative gravitropic response in the primary shoot that orientates it towards the source of light, and a positive gravitropic response in the primary root that causes it to grow down into the soil, providing support and nutrient acquisition. Gravity also influences plant form during later stages of development through its effect on lateral organs and supporting structures. Thus, the final form of a plant depends on the cumulative effects of light, gravity and other environmental sensory inputs on endogenous developmental programs. This article is focused on developmental interactions modulated by light and gravity.

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Section: Phytochrome and Phototropismmentioning

confidence: 93%

Gravity, light and plant form

Hangarter

1997

Plant Cell & Environment

179

124

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“…Whatever the exact mechanism, recent evidence that phyA is expressed in the root cap of Arabidopsis (Hall et al, 2001), where light sensing occurs, supports our observations that phyA plays a role in the root phototropic response. Furthermore, whereas the blue-light receptor family of phototropins (Briggs and Christie, 2002) function in light perception mechanisms of phototropism in stems and stem-like organs, phyA (Parks et al, 1996) and phyB (Janoudi and Poff, 1997) have been shown to regulate red-and far-red induction of phototropic enhancement in hypocotyls.…”

Section: Discussionmentioning

confidence: 99%

Phytochromes A and B Mediate Red-Light-Induced Positive Phototropism in Roots

et al. 2003

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(J.L.M., R.P.H.)The interaction of tropisms is important in determining the final growth form of the plant body. In roots, gravitropism is the predominant tropistic response, but phototropism also plays a role in the oriented growth of roots in flowering plants. In blue or white light, roots exhibit negative phototropism that is mediated by the phototropin family of photoreceptors. In contrast, red light induces a positive phototropism in Arabidopsis roots. Because this red-light-induced response is weak relative to both gravitropism and negative phototropism, we used a novel device to study phototropism without the complications of a counteracting gravitational stimulus. This device is based on a computer-controlled system using real-time image analysis of root growth and a feedback-regulated rotatable stage. Our data show that this system is useful to study root phototropism in response to red light, because in wild-type roots, the maximal curvature detected with this apparatus is 30°to 40°, compared with 5°to 10°without the feedback system. In positive root phototropism, sensing of red light occurs in the root itself and is not dependent on shoot-derived signals resulting from light perception. Phytochrome (Phy)A and phyB were severely impaired in red-light-induced phototropism, whereas the phyD and phyE mutants were normal in this response. Thus, PHYA and PHYB play a key role in mediating red-light-dependent positive phototropism in roots. Although phytochrome has been shown to mediate phototropism in some lower plant groups, this is one of the few reports indicating a phytochrome-dependent phototropism in flowering plants.Plants have evolved selective and sensitive mechanisms to deal with the constant sensory input they receive from the environment. In roots, gravity is the most critical signal for growth and development, and, thus, gravitropism has been well-characterized in this organ (Sack, 1991;Kiss, 2000). However, it has become increasingly clear that gravitropism interacts with a number of other tropistic responses including phototropism, thigmotropism, and hydrotropism in determining the final growth form of the primary root and the entire root system (Hangarter, 1997;Correll and Kiss, 2002).Phototropism in roots was extensively reviewed in a classical paper by Hubert and Funke (1937) but has received increased attention since the report by Okada and Shimura (1992), who isolated mutants in root phototropism that were later shown to be deficient in the blue-light receptor PHOT1 (Briggs and Christie, 2002). Roots are typically negatively phototropic in response to white and blue light (Okada and Shimura, 1992;Vitha et al., 2000) and use the same photoreceptors that are involved in phototropism in stems and stem-like organs (Sakai et al., 2000). Furthermore, similar to root gravisensing (Blancaflor et al., 1998), sensing of blue light for phototropism occurs in the root cap .We have recently identified a red-light-induced positive phototropism in primary roots of Arabidopsis ). This tropistic response ...

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“…29 More recently, studies demonstrated that the phytochrome signaling component PHYTOCHROME KINASE SUBSTRATE 1 (PKS1) protein is required for hypocotyl phototropism in A. thaliana and PKS1 can form a complex with PHOT1 and NPH3. 30 Since phytochromes (and cryptochromes) influence phototropic curvature in A. thaliana as well, 31 PKS proteins may constitute a link between the photoreceptor families.…”

Section: Photoreceptorsmentioning

confidence: 99%

Physiological regulation and functional significance of shade avoidance responses to neighbors

Keuskamp

Sasidharan

Pierik

2010

Plant Signaling & Behavior

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Besides being a source of energy, light is also a source of information that plants can respond to. Most plants are able to react to the direction, intensity, composition and duration of light. These light components regulate such features as seed germination, photomorphogenesis, flowering time and the SAS. [10][11][12] The SAS encompasses various phenotypic traits (Fig. 1), including elongation of internodes, petioles and hypocotyls, apical dominance, early flowering and upward leaf movement (hyponasty).

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Multiple Phytochromes Are Involved in Red-Light-Induced Enhancement of First-Positive Phototropism in Arabidopsis thaliana

Cited by 88 publications

References 11 publications

Gravity, light and plant form

Gravity, light and plant form

Phytochromes A and B Mediate Red-Light-Induced Positive Phototropism in Roots

Physiological regulation and functional significance of shade avoidance responses to neighbors

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