Hormonal cross-talk drives nutrient dependent plant development
Exploitation and acquisition of nutrients from the soil is one of the most challenging aspects of plant adaptation to a sessile life-style. Plant must cope with varying availabilities of mineral elements and secure their optimal income into plant body. This is achieved through adjustment of mechanisms and pathways mediating soil exploitation, uptake of elements, and distribution within the plant body. This vital function of effective soil exploitation and balanced acquisition of all elements is executed by a root organ. In the soil, the root system perceives and integrates local and systemic signals on the plant’s nutrient status to regulate activity of pathways mediating nutrient uptake and distribution. An important component of this nutrient management strategy involves rapid modulation of root growth and development. In response to nutrient availability, root meristem activity, root elongation growth as well as branching pattern are adjusted in order to optimize nutrient provision to the plant body. Plant hormone auxin and its tightly controlled polar distribution mediated by specific transporters from at least three families (PIN, AUX/LAX and PGP) play one of the prominent role in this dynamic plant developmental adaptations. Importantly, plant hormones do not act exclusively downstream of the exogenous signals, but actively feedback on mechanisms involved in nutrient acquisition and thus constitute retro-control of growth on nutrient uptake and assimilation. Hence complex nutrient –hormonal regulatory network consisting of feedback – forward loops operates in plants to control plant behavior in response to fluctuating nitrogen environments. However molecular mechanisms underlying this nutrient – hormones regulated plant development are scarcely understood so far. The main focus of our project is on mechanisms integrating nitrate and hormonal regulation of root growth and development. To address the objectives of the project we are following complementary research strategies focusing on:
- Mechanisms of auxin transport adaptation to nitrate availability,
- Interplay between nitrate and hormones in regulation of auxin transport directing root development,
- Posttranscriptional modification as mechanisms of nitrate regulated auxin transport.
Arabidopsis Col-0 seedlings grown on nitrate perform better than seedlings grown on ammonium containing media. Root growth kinetic measurements show increased primary root growth in case of nitrate treatments.
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To explore and monitor adaptive developmental and molecular responses of the root system to nitrate availability we have established unique visualization platform – a vertical confocal microscope (LSM700) equipped with root tracker software which enabled long term (over 12h) observations of root growth in real time. Using this setup we were able to monitor the earliest changes in primary root growth upon nitrate treatment.
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This work was supported by an Austrian Science Fund grant (FWF01_I1774S).
Publications connected to this project:
- von Wangenheim D, Hauschild R, Fendrych M, Barone V, Benková E and Friml J. (2017) Live tracking of moving samples in confocal microscopy for vertically grown roots. eLife, 2017;6:e26792.
- Ӧtvӧs K and Benková E. (2017) Spatiotemporal mechanisms of root branching. Current Opinion in Genetics & Development, 2017, 45:82–89.
- Hurný A, Benková E. (2017) Methodological Advances in Auxi n and Cytokinin Biology. Methods inMolecular Biology, vol 1569:1-29. Humana Press, New York, NY.
- Bouguyon E, Perrine-Walker F, Pervent M, Rochette J, Cuesta C, Benková E, Martinière A, BachL, Krouk G1, Gojon A, Nacry P (2016) Nitrate Controls Root Development through Posttranscriptional Regulation of the NRT1.1/NPF6.3 Transporter/Sensor. Plant Physiology, 2016, 172(2):1237-1248.
- Zhu Q, Benková E. (2016) Seedlings’ Strategy to Overcome a Soil Barrier. Trends in Plant Science. 2016, 21(10):809-811.
- Marhavý P, Montesinos JC, Abuzeineh A, Van Damme D, Vermeer JE, Duclercq J, Rakusová H, Nováková P, Friml J, Geldner N, Benková E. (2016) Targeted cell elimination reveals an auxin-guided biphasic mode of lateral root initiation. Genes and Development. 2016, 30(4):471-83.
- Šimášková M, O’Brien JA, Khan M, Van Noorden G, Ötvös K, Vieten A, De Clercq I, Van Haperen JM, Cuesta C, Hoyerová K, Vanneste S, Marhavý P, Wabnik K, Van Breusegem F, Nowack M, Murphy A, Friml J, Weijers D, Beeckman T, Benková E. (2015): Cytokinin response factors regulate PIN-FORMED auxin transporters. Nature Communication. 2015, 6:8717.