Inducible knock-down of GNOM during root formation reveals tissue-specific response to auxin transport and its modulation of local auxin biosynthesis

SummaryThe plant hormone auxin (indole-3-acetic acid, IAA) has a profound influence over plant cell growth and differentiation. Current understanding of vein development in leaves is based on the canalization of auxin into self-reinforcing streams which determine the sites of vascular cell differentiation. However, the role of auxin biosynthesis during leaf development in the context of leaf vein patterning has not been much studied so far. Here we characterize the context specific importance of auxin biosynthesis, auxin transport and mechanical regulations in a growing leaf. We show that domains of auxin biosynthesis predict the positioning of vascular cells. In mutants that have reduced capacity in auxin biosynthesis, leaf vein formation is decreased. While exogenous application of auxin does not compensate the loss of vein formation in auxin biosynthesis mutants, inhibition of polar auxin transport does compensate the vein-less phenotype, suggesting that the site-specific accumulation of auxin, which is likely to be mainly caused by the local auxin biosynthesis, is important for leaf vein formation. Our computational model of midvein development brings forth the interplay of cell stiffness and auxin dependent cell division. We propose that local auxin biosynthesis has the integral role in leaf vascular development.HighlightsBuilt spatially and temporally resolved auxin biosynthesis map in growing leaf primordium of Arabidopsis.Expression domains of auxin biosynthetic enzymes within primordia strongly correlated with leaf vein initiation.Results show that domains of auxin biosynthesis within primordia drive leaf vein initiation and patterning.Highlights and eTOC BlurbUsing modelling and a spatiotemporal analysis of auxin biosynthesis and transport, Kneuper et al. show that tissue specific auxin biosynthesis defines places of vein initiation hence underlining the importance of auxin concentration in vein initiation.

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Membrane Sterol Composition in Arabidopsis thaliana Affects Root Elongation via Auxin Biosynthesis

International Journal of Molecular Sciences ◽

10.3390/ijms22010437 ◽

2021 ◽

Vol 22 (1) ◽

pp. 437

Author(s):

Meng Wang ◽

Panpan Li ◽

Yao Ma ◽

Xiang Nie ◽

Markus Grebe ◽

...

Keyword(s):

Root Elongation ◽

Auxin Transport ◽

Sterol Composition ◽

Polar Auxin Transport ◽

Sterol Biosynthesis ◽

Auxin Biosynthesis ◽

Root Tip ◽

Auxin Signaling ◽

Auxin Response ◽

Short Root

Plant membrane sterol composition has been reported to affect growth and gravitropism via polar auxin transport and auxin signaling. However, as to whether sterols influence auxin biosynthesis has received little attention. Here, by using the sterol biosynthesis mutant cyclopropylsterol isomerase1-1 (cpi1-1) and sterol application, we reveal that cycloeucalenol, a CPI1 substrate, and sitosterol, an end-product of sterol biosynthesis, antagonistically affect auxin biosynthesis. The short root phenotype of cpi1-1 was associated with a markedly enhanced auxin response in the root tip. Both were neither suppressed by mutations in polar auxin transport (PAT) proteins nor by treatment with a PAT inhibitor and responded to an auxin signaling inhibitor. However, expression of several auxin biosynthesis genes TRYPTOPHAN AMINOTRANSFERASE OF ARABIDOPSIS1 (TAA1) was upregulated in cpi1-1. Functionally, TAA1 mutation reduced the auxin response in cpi1-1 and partially rescued its short root phenotype. In support of this genetic evidence, application of cycloeucalenol upregulated expression of the auxin responsive reporter DR5:GUS (β-glucuronidase) and of several auxin biosynthesis genes, while sitosterol repressed their expression. Hence, our combined genetic, pharmacological, and sterol application studies reveal a hitherto unexplored sterol-dependent modulation of auxin biosynthesis during Arabidopsis root elongation.

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Control of auxin-regulated root development by the Arabidopsis thaliana SHY2/IAA3 gene

Development ◽

10.1242/dev.126.4.711 ◽

1999 ◽

Vol 126 (4) ◽

pp. 711-721 ◽

Cited By ~ 14

Author(s):

Q. Tian ◽

J.W. Reed

Keyword(s):

Arabidopsis Thaliana ◽

Lateral Root ◽

Tissue Specificity ◽

Plant Hormone ◽

Root Formation ◽

Auxin Transport ◽

Feedback Regulation ◽

Loss Of Function ◽

Leaf Formation ◽

Induced Genes

The plant hormone auxin controls many aspects of development and acts in part by inducing expression of various genes. Arabidopsis thaliana semidominant shy2 (short hypocotyl) mutations cause leaf formation in dark-grown plants, suggesting that SHY2 has an important role in regulating development. Here we show that the SHY2 gene encodes IAA3, a previously known member of the Aux/IAA family of auxin-induced genes. Dominant shy2 mutations cause amino acid changes in domain II, conserved among all members of this family. We isolated loss-of-function shy2 alleles including a putative null mutation. Gain-of-function and loss-of-function shy2 mutations affect auxin-dependent root growth, lateral root formation, and timing of gravitropism, indicating that SHY2/IAA3 regulates multiple auxin responses in roots. The phenotypes suggest that SHY2/IAA3 may activate some auxin responses and repress others. Models invoking tissue-specificity, feedback regulation, or control of auxin transport may explain these results.

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Tissue-specific response of δ15N in adult Pacific herring (Clupea pallasi) following an isotopic shift in diet

Environmental Biology of Fishes ◽

10.1007/s10641-006-9020-9 ◽

2006 ◽

Vol 76 (2-4) ◽

pp. 177-189 ◽

Cited By ~ 35

Author(s):

Todd W. Miller

Keyword(s):

Isotopic Shift ◽

Specific Response ◽

Pacific Herring ◽

Tissue Specific ◽

Clupea Pallasi

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Corticosterone tissue-specific response in Sprague Dawley rats under acute heat stress

Journal of Thermal Biology ◽

10.1016/j.jtherbio.2019.02.004 ◽

2019 ◽

Vol 81 ◽

pp. 12-19 ◽

Cited By ~ 1

Author(s):

Jinhuan Dou ◽

Yuri R. Montanholi ◽

Zezhao Wang ◽

Zhongshu Li ◽

Ying Yu ◽

...

Keyword(s):

Heat Stress ◽

Specific Response ◽

Sprague Dawley ◽

Tissue Specific ◽

Sprague Dawley Rats ◽

Acute Heat Stress

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Effect of polar auxin transport and gibberellins on xylem formation in pine cuttings under adventitious rooting conditions

Israel Journal of Plant Sciences ◽

10.1163/22238980-20191120 ◽

2020 ◽

Vol 67 (1-2) ◽

pp. 27-39 ◽

Cited By ~ 1

Author(s):

Alberto Pizarro ◽

Carmen Díaz-Sala

Keyword(s):

Adventitious Root ◽

Root Formation ◽

Auxin Transport ◽

Adventitious Rooting ◽

Adventitious Root Formation ◽

Polar Auxin Transport ◽

Root Induction ◽

Xylem Differentiation ◽

Xylem Formation ◽

Hypocotyl Cuttings

Maturation-related decline of adventitious root formation is one of the major factors affecting adventitious rooting in forest tree species. We demonstrate that inhibition of polar auxin transport promoted cambium and xylem differentiation in rooting-competent hypocotyl cuttings from Pinus radiata under conditions of adventitious root formation. Treatments with bioactive gibberellins inhibited rooting while at the same time inducing both the differentiation of a continuous ring of cambium and xylem formation. Treatments with inhibitors of gibberellin biosynthesis did not affect the rooting response. The results demonstrate that xylem parenchyma and procambial cells at the xylem poles of rooting-competent hypocotyl cuttings after excision and under conditions of adventitious root induction become adventitious root meristems or xylem, depending on the directional auxin flow. Gibberellin may interact with this pathway, inducing xylem differentiation and inhibiting rooting. We conclude that modifications of auxin flow at the rooting sites, and the priming of cambial cells to differentiate into xylem during tree ageing, may be associated with the maturation-related decline of adventitious root formation.

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Sugar enhances waterlogging‐induced adventitious root formation in cucumber by promoting auxin transport and signalling

Plant Cell & Environment ◽

10.1111/pce.13738 ◽

2020 ◽

Vol 43 (6) ◽

pp. 1545-1557 ◽

Cited By ~ 1

Author(s):

Xiaohua Qi ◽

Qianqian Li ◽

Jiatao Shen ◽

Chunlu Qian ◽

Xuewen Xu ◽

...

Keyword(s):

Adventitious Root ◽

Root Formation ◽

Auxin Transport ◽

Adventitious Root Formation

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Ontogenetic Changes in Auxin Biosynthesis and Distribution Determine the Organogenic Activity of the Shoot Apical Meristem in pin1 Mutants

International Journal of Molecular Sciences ◽

10.3390/ijms20010180 ◽

2019 ◽

Vol 20 (1) ◽

pp. 180 ◽

Cited By ~ 3

Author(s):

Alicja Banasiak ◽

Magdalena Biedroń ◽

Alicja Dolzblasz ◽

Mateusz Adam Berezowski

Keyword(s):

Shoot Apical Meristem ◽

Apical Meristem ◽

Auxin Transport ◽

Vascular System ◽

Auxin Biosynthesis ◽

Wild Type ◽

Ontogenetic Changes ◽

Auxin Distribution ◽

Stem Development ◽

Knockout Mutation

In the shoot apical meristem (SAM) of Arabidopsis, PIN1-dependent polar auxin transport (PAT) regulates two crucial developmental processes: organogenesis and vascular system formation. However, the knockout mutation in the PIN1 gene does not fully inhibit these two processes. Therefore, we investigated a potential source of auxin for organogenesis and vascularization during inflorescence stem development. We analyzed auxin distribution in wild-type (WT) and pin1 mutant plants using a refined protocol of auxin immunolocalization; auxin activity, with the response reporter pDR5:GFP; and expression of auxin biosynthesis genes YUC1 and YUC4. Our results revealed that regardless of the functionality of PIN1-mediated PAT, auxin is present in the SAM and vascular strands. In WT plants, auxin always accumulates in all cells of the SAM, whereas in pin1 mutants, its localization within the SAM changes ontogenetically and is related to changes in the structure of the vascular system, organogenic activity of SAM, and expression levels of YUC1 and YUC4 genes. Our findings indicate that the presence of auxin in the meristem of pin1 mutants is an outcome of at least two PIN1-independent mechanisms: acropetal auxin transport from differentiated tissues with the use of vascular strands and auxin biosynthesis within the SAM.

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Akt3 Regulates the Tissue-Specific Response to Copaiba Essential Oil

International Journal of Molecular Sciences ◽

10.3390/ijms21082851 ◽

2020 ◽

Vol 21 (8) ◽

pp. 2851

Author(s):

Yasuyo Urasaki ◽

Cody Beaumont ◽

Jeffery N. Talbot ◽

David K. Hill ◽

Thuc T. Le

Keyword(s):

Essential Oil ◽

Signaling Pathways ◽

Signaling Pathway ◽

Liver Cells ◽

Mtor Signaling ◽

Specific Response ◽

Mtor Signaling Pathway ◽

Tissue Specific ◽

Regulatory Effects ◽

Specific Regulation

This study reports a relationship between Akt3 expression and tissue-specific regulation of the pI3K/Akt/mTOR signaling pathway by copaiba essential oil. Akt3, a protein kinase B isoform important for the regulation of neuronal development, exhibited differential expression levels in cells of various origins. In neuronal and microglial cells, where Akt3 is present, copaiba essential oil positively regulated the pI3K/Akt/mTOR signaling pathway. In contrast, in liver cells and T lymphocytes, where Akt3 is absent, copaiba essential oil negatively regulated the pI3K/Akt/mTOR signaling pathway. The expression of Akt3 via plasmid DNA in liver cells led to positive regulatory effects by copaiba essential oil on the pI3K/Akt/mTOR signaling pathway. In contrast, inhibition of Akt3 expression in neuronal cells via small interfering RNA molecules targeting Akt3 transcripts abrogated the regulatory effects of copaiba essential oil on the pI3K/Akt/mTOR signaling pathway. Interestingly, Akt3 expression did not impact the regulatory effects of copaiba essential oil on other signaling pathways. For example, copaiba essential oil consistently upregulated the MAPK and JAK/STAT signaling pathways in all evaluated cell types, independent of the Akt3 expression level. Collectively, the data indicated that Akt3 expression was required for the positive regulatory effects of copaiba essential oil, specifically on the pI3K/Akt/mTOR signaling pathway.

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Hypoxia induces a time- and tissue-specific response that elicits intertissue circadian clock misalignment

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1914112117 ◽

2019 ◽

Vol 117 (1) ◽

pp. 779-786 ◽

Cited By ~ 10

Author(s):

Gal Manella ◽

Rona Aviram ◽

Nityanand Bolshette ◽

Sapir Muvkadi ◽

Marina Golik ◽

...

Keyword(s):

Circadian Clock ◽

Ex Vivo ◽

Acute Hypoxia ◽

Time Of Day ◽

Chronic Obstructive ◽

Specific Response ◽

Dependent Manner ◽

Tissue Specific ◽

Circadian Misalignment ◽

Obstructive Sleep

The occurrence and sequelae of disorders that lead to hypoxic spells such as asthma, chronic obstructive pulmonary disease, and obstructive sleep apnea (OSA) exhibit daily variance. This prompted us to examine the interaction between the hypoxic response and the circadian clock in vivo. We found that the global transcriptional response to acute hypoxia is tissue-specific and time-of-day–dependent. In particular, clock components differentially responded at the transcriptional and posttranscriptional level, and these responses depended on an intact circadian clock. Importantly, exposure to hypoxia phase-shifted clocks in a tissue-dependent manner led to intertissue circadian clock misalignment. This differential response relied on the intrinsic properties of each tissue and could be recapitulated ex vivo. Notably, circadian misalignment was also elicited by intermittent hypoxia, a widely used model for OSA. Given that phase coherence between circadian clocks is considered favorable, we propose that hypoxia leads to circadian misalignment, contributing to the pathophysiology of OSA and potentially other diseases that involve hypoxia.

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