Saturated humidity accelerates lateral root development in rice (Oryza sativa L.) seedlings by increasing phloem-based auxin transport

Chhun, Tory; Uno, Yuichi; Taketa, Shin; Azuma, Tetsushi; Ichii, Masahiko; Okamoto, Takashi; Tsurumi, Seiji

doi:10.1093/jxb/erm026

Cited by 38 publications

(25 citation statements)

References 41 publications

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“…Furthermore, experiments with the IAA transport inhibitor NPA show that IAA movement through the root tip is essential for lateral root initiation, whereas shoot-derived transport is required for lateral root emergence (Casimiro et al 2001). In contrast, stimulation of the shoot-to-root transport by growing rice plants in saturated humidity increased the number of emerged lateral roots (Chhun et al 2007). Unfortunately, in the latter study, the authors did not make a distinction between emerged and nonemerged lateral roots thus leaving open the question of whether in rice the shoot-derived auxin was stimulatory specifically for emergence or rather served to promote the entire lateral root formation process, including initiation.…”

Section: Lateral Root Development Relies On Both Root-and Shoot-derivmentioning

confidence: 99%

Auxin Control of Root Development

Overvoorde

Fukaki²,

Beeckman

2010

Cold Spring Harbor Perspectives in Biology

651

454

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A plant's roots system determines both the capacity of a sessile organism to acquire nutrients and water, as well as providing a means to monitor the soil for a range of environmental conditions. Since auxins were first described, there has been a tight connection between this class of hormones and root development. Here we review some of the latest genetic, molecular, and cellular experiments that demonstrate the importance of generating and maintaining auxin gradients during root development. Refinements in the ability to monitor and measure auxin levels in root cells coupled with advances in our understanding of the sources of auxin that contribute to these pools represent important contributions to our understanding of how this class of hormones participates in the control of root development. In addition, we review the role of identified molecular components that convert auxin gradients into local differentiation events, which ultimately defines the root architecture.

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Section: Lateral Root Development Relies On Both Root-and Shoot-derivmentioning

confidence: 99%

Auxin Control of Root Development

Overvoorde

Fukaki²,

Beeckman

2010

Cold Spring Harbor Perspectives in Biology

651

454

View full text Add to dashboard Cite

show abstract

“…Tables I and III). Since auxin is known to play a role in plant growth and lateral root formation (Woodward and Bartel, 2005;Teale et al, 2006;Chhun et al, 2007), free IAA level was measured in wild-type and OX plants. Figure 3A shows that free IAA in shoots of 4-week-old OX plants was 20% lower than in wild-type plants.…”

Section: Overexpression Of Saur39 Inhibits Growth and Yield Of Rice Pmentioning

confidence: 99%

SAUR39, a Small Auxin-Up RNA Gene, Acts as a Negative Regulator of Auxin Synthesis and Transport in Rice

Kant

Bi²,

Zhu³

et al. 2009

Plant Physiology

257

185

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The phytohormone auxin plays a critical role for plant growth by regulating the expression of a set of genes. One large auxinresponsive gene family of this type is the small auxin-up RNA (SAUR) genes, although their function is largely unknown. The expression of the rice (Oryza sativa) SAUR39 gene showed rapid induction by transient change in different environmental factors, including auxin, nitrogen, salinity, cytokinin, and anoxia. Transgenic rice plants overexpressing the SAUR39 gene resulted in lower shoot and root growth, altered shoot morphology, smaller vascular tissue, and lower yield compared with wild-type plants. The SAUR39 gene was expressed at higher levels in older leaves, unlike auxin biosynthesis, which occurs largely in the meristematic region. The transgenic plants had a lower auxin level and a reduced polar auxin transport as well as the down-regulation of some putative auxin biosynthesis and transporter genes. Biochemical analysis also revealed that transgenic plants had lower chlorophyll content, higher levels of anthocyanin, abscisic acid, sugar, and starch, and faster leaf senescence compared with wild-type plants at the vegetative stage. Most of these phenomena have been shown to be negatively correlated with auxin level and transport. Transcript profiling revealed that metabolic perturbations in overexpresser plants were largely due to transcriptional changes of genes involved in photosynthesis, senescence, chlorophyll production, anthocyanin accumulation, sugar synthesis, and transport. The lower growth and yield of overexpresser plants was largely recovered by exogenous auxin application. Taken together, the results suggest that SAUR39 acts as a negative regulator for auxin synthesis and transport.

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“…Because the overexpression of MIZ1 negatively regulates lateral root formation, it is thought that MIZ1-dependent inhibition does not work in the miz1 mutant even under drought conditions, and miz1 showed an osmotic stress-tolerant phenotype on lateral root formation. Furthermore, drought stress inhibits auxin accumulation in roots and lateral root formation in rice roots (Chhun et al, 2007). Therefore, it is possible that the osmotic stress-tolerant phenotype of miz1 on lateral root formation is somewhat dependent on its elevated auxin content.…”

Section: Miz1 Contributes To Lateral Root Formation Under Osmotic Strmentioning

confidence: 99%

Hormonal Regulation of Lateral Root Development in Arabidopsis Modulated byMIZ1and Requirement of GNOM Activity forMIZ1Function

et al. 2011

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Plant organ development is important for adaptation to a changing environment. Genetic and physiological studies have revealed that plant hormones play key roles in lateral root formation. In this study, we show that MIZU-KUSSEI1 (MIZ1), which was identified originally as a regulator of hydrotropism, functions as a novel regulator of hormonally mediated lateral root development. Overexpression of MIZ1 (MIZ1OE) in roots resulted in a reduced number of lateral roots being formed; however, this defect could be recovered with the application of auxin. Indole-3-acetic acid quantification analyses showed that free indole-3-acetic acid levels decreased in MIZ1OE roots, which indicates that alteration of auxin level is critical for the inhibition of lateral root formation in MIZ1OE plants. In addition, MIZ1 negatively regulates cytokinin sensitivity on root development. Application of cytokinin strongly induced the localization of MIZ1-green fluorescent protein to lateral root primordia, which suggests that the inhibition of lateral root development by MIZ1 occurs downstream of cytokinin signaling. Surprisingly, miz2, a weak allele of gnom, suppressed developmental defects in MIZ1OE plants. Taken together, these results suggest that MIZ1 plays a role in lateral root development by maintaining auxin levels and that its function requires GNOM activity. These data provide a molecular framework for auxin-dependent organ development in Arabidopsis (Arabidopsis thaliana).

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Saturated humidity accelerates lateral root development in rice (Oryza sativa L.) seedlings by increasing phloem-based auxin transport

Cited by 38 publications

References 41 publications

Auxin Control of Root Development

Auxin Control of Root Development

SAUR39, a Small Auxin-Up RNA Gene, Acts as a Negative Regulator of Auxin Synthesis and Transport in Rice

Hormonal Regulation of Lateral Root Development in Arabidopsis Modulated byMIZ1and Requirement of GNOM Activity forMIZ1Function

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