Limits...
Glucose and auxin signaling interaction in controlling Arabidopsis thaliana seedlings root growth and development.

Mishra BS, Singh M, Aggrawal P, Laxmi A - PLoS ONE (2009)

Bottom Line: Interestingly, glucose could affect induction or repression of IAA affected genes (35%) even if glucose alone had no significant effect on the transcription of these genes itself.Arabidopsis auxin receptor tir1 and response mutants, axr2, axr3 and slr1 not only display a defect in glucose induced change in root length, root hair elongation and lateral root production but also accentuate glucose induced increase in root growth randomization from vertical suggesting glucose effects on plant root growth and development are mediated by auxin signaling components.Our findings implicate an important role of the glucose interacting with auxin signaling and transport machinery to control seedling root growth and development in changing nutrient conditions.

View Article: PubMed Central - PubMed

Affiliation: National Institute for Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, India.

ABSTRACT

Background: Plant root growth and development is highly plastic and can adapt to many environmental conditions. Sugar signaling has been shown to affect root growth and development by interacting with phytohormones such as gibberellins, cytokinin and abscisic acid. Auxin signaling and transport has been earlier shown to be controlling plant root length, number of lateral roots, root hair and root growth direction.

Principal findings: Increasing concentration of glucose not only controls root length, root hair and number of lateral roots but can also modulate root growth direction. Since root growth and development is also controlled by auxin, whole genome transcript profiling was done to find out the extent of interaction between glucose and auxin response pathways. Glucose alone could transcriptionally regulate 376 (62%) genes out of 604 genes affected by IAA. Presence of glucose could also modulate the extent of regulation 2 fold or more of almost 63% genes induced or repressed by IAA. Interestingly, glucose could affect induction or repression of IAA affected genes (35%) even if glucose alone had no significant effect on the transcription of these genes itself. Glucose could affect auxin biosynthetic YUCCA genes family members, auxin transporter PIN proteins, receptor TIR1 and members of a number of gene families including AUX/IAA, GH3 and SAUR involved in auxin signaling. Arabidopsis auxin receptor tir1 and response mutants, axr2, axr3 and slr1 not only display a defect in glucose induced change in root length, root hair elongation and lateral root production but also accentuate glucose induced increase in root growth randomization from vertical suggesting glucose effects on plant root growth and development are mediated by auxin signaling components.

Conclusion: Our findings implicate an important role of the glucose interacting with auxin signaling and transport machinery to control seedling root growth and development in changing nutrient conditions.

Show MeSH
Comparison of root growth and development of Col seedlings grown in different concentrations of glucose containing medium.(A) Root growth, lateral roots, seedling morphology and root hair formation of 5 d old Col seedlings transferred to increasing concentrations of glucose containing medium for 2–5 days. (B) 5 d old light-grown Col seedlings root angle deviation from vertical increases on transferring them to increasing concentration of glucose containing medium for 2 d. (C) Comparative graph of root length of 5 d old Col light-grown seedlings shifted to different concentration of glucose containing medium for 2 d. The root length increases on increasing glucose concentration up to 3% but decreases if the concentration is increased to 5% or more. Average of 10 seedlings was taken and error bar represents standard deviation. (D) Comparative graph of lateral roots of 5 d old Col light-grown seedlings shifted to different concentration of glucose containing medium for 5 d. Number of lateral roots increase on increasing glucose concentration up to 3% but decrease if the concentration is increased to 5% or more. Average of 10 seedlings was taken and error bar represents standard deviation. (E) Comparative graph of root angle deviation from vertical of 5 d old Col light-grown seedlings shifted to different concentration of glucose containing medium for 2 d. Root angle deviation of Col seedlings from vertical increases on increasing glucose concentrations. Average of 10 seedlings was taken and error bar represents standard deviation.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2637607&req=5

pone-0004502-g001: Comparison of root growth and development of Col seedlings grown in different concentrations of glucose containing medium.(A) Root growth, lateral roots, seedling morphology and root hair formation of 5 d old Col seedlings transferred to increasing concentrations of glucose containing medium for 2–5 days. (B) 5 d old light-grown Col seedlings root angle deviation from vertical increases on transferring them to increasing concentration of glucose containing medium for 2 d. (C) Comparative graph of root length of 5 d old Col light-grown seedlings shifted to different concentration of glucose containing medium for 2 d. The root length increases on increasing glucose concentration up to 3% but decreases if the concentration is increased to 5% or more. Average of 10 seedlings was taken and error bar represents standard deviation. (D) Comparative graph of lateral roots of 5 d old Col light-grown seedlings shifted to different concentration of glucose containing medium for 5 d. Number of lateral roots increase on increasing glucose concentration up to 3% but decrease if the concentration is increased to 5% or more. Average of 10 seedlings was taken and error bar represents standard deviation. (E) Comparative graph of root angle deviation from vertical of 5 d old Col light-grown seedlings shifted to different concentration of glucose containing medium for 2 d. Root angle deviation of Col seedlings from vertical increases on increasing glucose concentrations. Average of 10 seedlings was taken and error bar represents standard deviation.

Mentions: There are several reports that sugar can influence/modulate plant root length or number of adventitious roots. Interestingly, in our experiments, we observed that increasing concentration of glucose not only increases root length, number of lateral roots and root hair but also modulates gravitropic response of the primary roots of young seedlings. The 5-d-old light-grown Col seedlings shifted to ½ Murashige and Skoog (MS) medium containing various concentrations of glucose displayed not only a change in root length, number of lateral roots, root hair but also the direction of the roots gets more randomized (Figure 1). Presence of 3-O-methylglucose (3-OMG) (non-signaling glucose analog) in the medium could not affect root length, lateral roots and root gravitropism as extensively as is caused by glucose suggesting glucose specificity rather then the osmotic effects to be responsible for these responses (Figure S1).


Glucose and auxin signaling interaction in controlling Arabidopsis thaliana seedlings root growth and development.

Mishra BS, Singh M, Aggrawal P, Laxmi A - PLoS ONE (2009)

Comparison of root growth and development of Col seedlings grown in different concentrations of glucose containing medium.(A) Root growth, lateral roots, seedling morphology and root hair formation of 5 d old Col seedlings transferred to increasing concentrations of glucose containing medium for 2–5 days. (B) 5 d old light-grown Col seedlings root angle deviation from vertical increases on transferring them to increasing concentration of glucose containing medium for 2 d. (C) Comparative graph of root length of 5 d old Col light-grown seedlings shifted to different concentration of glucose containing medium for 2 d. The root length increases on increasing glucose concentration up to 3% but decreases if the concentration is increased to 5% or more. Average of 10 seedlings was taken and error bar represents standard deviation. (D) Comparative graph of lateral roots of 5 d old Col light-grown seedlings shifted to different concentration of glucose containing medium for 5 d. Number of lateral roots increase on increasing glucose concentration up to 3% but decrease if the concentration is increased to 5% or more. Average of 10 seedlings was taken and error bar represents standard deviation. (E) Comparative graph of root angle deviation from vertical of 5 d old Col light-grown seedlings shifted to different concentration of glucose containing medium for 2 d. Root angle deviation of Col seedlings from vertical increases on increasing glucose concentrations. Average of 10 seedlings was taken and error bar represents standard deviation.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2637607&req=5

pone-0004502-g001: Comparison of root growth and development of Col seedlings grown in different concentrations of glucose containing medium.(A) Root growth, lateral roots, seedling morphology and root hair formation of 5 d old Col seedlings transferred to increasing concentrations of glucose containing medium for 2–5 days. (B) 5 d old light-grown Col seedlings root angle deviation from vertical increases on transferring them to increasing concentration of glucose containing medium for 2 d. (C) Comparative graph of root length of 5 d old Col light-grown seedlings shifted to different concentration of glucose containing medium for 2 d. The root length increases on increasing glucose concentration up to 3% but decreases if the concentration is increased to 5% or more. Average of 10 seedlings was taken and error bar represents standard deviation. (D) Comparative graph of lateral roots of 5 d old Col light-grown seedlings shifted to different concentration of glucose containing medium for 5 d. Number of lateral roots increase on increasing glucose concentration up to 3% but decrease if the concentration is increased to 5% or more. Average of 10 seedlings was taken and error bar represents standard deviation. (E) Comparative graph of root angle deviation from vertical of 5 d old Col light-grown seedlings shifted to different concentration of glucose containing medium for 2 d. Root angle deviation of Col seedlings from vertical increases on increasing glucose concentrations. Average of 10 seedlings was taken and error bar represents standard deviation.
Mentions: There are several reports that sugar can influence/modulate plant root length or number of adventitious roots. Interestingly, in our experiments, we observed that increasing concentration of glucose not only increases root length, number of lateral roots and root hair but also modulates gravitropic response of the primary roots of young seedlings. The 5-d-old light-grown Col seedlings shifted to ½ Murashige and Skoog (MS) medium containing various concentrations of glucose displayed not only a change in root length, number of lateral roots, root hair but also the direction of the roots gets more randomized (Figure 1). Presence of 3-O-methylglucose (3-OMG) (non-signaling glucose analog) in the medium could not affect root length, lateral roots and root gravitropism as extensively as is caused by glucose suggesting glucose specificity rather then the osmotic effects to be responsible for these responses (Figure S1).

Bottom Line: Interestingly, glucose could affect induction or repression of IAA affected genes (35%) even if glucose alone had no significant effect on the transcription of these genes itself.Arabidopsis auxin receptor tir1 and response mutants, axr2, axr3 and slr1 not only display a defect in glucose induced change in root length, root hair elongation and lateral root production but also accentuate glucose induced increase in root growth randomization from vertical suggesting glucose effects on plant root growth and development are mediated by auxin signaling components.Our findings implicate an important role of the glucose interacting with auxin signaling and transport machinery to control seedling root growth and development in changing nutrient conditions.

View Article: PubMed Central - PubMed

Affiliation: National Institute for Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, India.

ABSTRACT

Background: Plant root growth and development is highly plastic and can adapt to many environmental conditions. Sugar signaling has been shown to affect root growth and development by interacting with phytohormones such as gibberellins, cytokinin and abscisic acid. Auxin signaling and transport has been earlier shown to be controlling plant root length, number of lateral roots, root hair and root growth direction.

Principal findings: Increasing concentration of glucose not only controls root length, root hair and number of lateral roots but can also modulate root growth direction. Since root growth and development is also controlled by auxin, whole genome transcript profiling was done to find out the extent of interaction between glucose and auxin response pathways. Glucose alone could transcriptionally regulate 376 (62%) genes out of 604 genes affected by IAA. Presence of glucose could also modulate the extent of regulation 2 fold or more of almost 63% genes induced or repressed by IAA. Interestingly, glucose could affect induction or repression of IAA affected genes (35%) even if glucose alone had no significant effect on the transcription of these genes itself. Glucose could affect auxin biosynthetic YUCCA genes family members, auxin transporter PIN proteins, receptor TIR1 and members of a number of gene families including AUX/IAA, GH3 and SAUR involved in auxin signaling. Arabidopsis auxin receptor tir1 and response mutants, axr2, axr3 and slr1 not only display a defect in glucose induced change in root length, root hair elongation and lateral root production but also accentuate glucose induced increase in root growth randomization from vertical suggesting glucose effects on plant root growth and development are mediated by auxin signaling components.

Conclusion: Our findings implicate an important role of the glucose interacting with auxin signaling and transport machinery to control seedling root growth and development in changing nutrient conditions.

Show MeSH