Daniel Schachtman, Ph.D.
Member (Corn Nitrogen Platform Lead, Monsanto Company as of September, 2008)
The main focus of the lab is to identify key mechanisms by which roots regulate
mineral uptake and adapt to changing soil conditions such as drought and
nutrient deficiencies.
dschachtman@danforthcenter.org
Nutrient sensing and signaling with changes in mineral uptake using stable istopes and other
Aims: Identify components of the signal transduction networks physiological parameters in a tomato wild type and in a tomato
involved in sensing and signaling changes in the concentration of mutant that does not form associations with mycorrhizal fungi.
nutrients s in soils. Apply this knowledge to increasing the nutrient
use efficiency of crop plants. Increasing the bioavailability of zinc in cassava
Background: Adaptation to changes in soil fertility is critical for Broad Aim: To increase the zinc content of cassava by six fold.
crop productivity and to reduce fertilizer usage, thereby decreasing Background: Cassava is a staple food that is very low in vitamins,
water pollution and increasing yield when soil fertility is low. It is minerals and protein. Zinc is one of the most limiting micronutrients
not known how plant roots sense or signal the changes that occur in human diets. Zinc deficiency reduces immunity and cognitive
during nutrient deficiency. abilities. The approach we are using is based on our previous work
Progress: We studied the global regulation of gene expression in which we increased the zinc content of seeds by overexpression
under nutrient deficiency in both Arabidopsis and corn roots. Using of ZIP1 (Ramesh, et al. 2004 Plant Mol Biol 54:373-385).
microarrays we identified genes and biochemical processes involved Progress: We have generated over 150 transgenic lines and
in the response to deficiency. This work led to the discovery that analyzed the zinc content of the fleshy edible part of the tuber in
the signaling molecule hydrogen peroxide plays a role in response 60 transgenic lines. We identified one line with over 800% higher
to nutrient deprivation in Arabidopsis roots. We have identified and many other lines with between 150 – 350% higher zinc content
several key plant hormones including auxin, ethylene and ABA as than parental lines. These lines express ZAT1, is a vacuolar zinc
playing important roles in root response to low nutrients. Our work transporter, or ZIP1, a plasma membrane zinc transporter whose
to elucidate nutrient signal transduction pathways continues with expression is driven by the patatin promoter. We are currently field
studies on factors that are regulated by SnRK2.8 phosphorylation testing selected lines in Puerto Rico and Missouri to determine how
and through screening a promoter luciferase fusion activation zinc accumulates under normal growth conditions.
tagged library which has yielded two additional components of the
transduction pathway – a transcription factor and a peroxidase. Providing drought tolerance to crop plants
through modification of suberin deposition in roots
A genomic and physiology approach to understanding the Broad Aims: To create plants with modified suberin in roots and
impact of mycorrhizal fungal colonization on root metabolism then test for drought tolerance and root hydraulic conductance.
and nutrient acquisition from nutrient patches Background: As water resources in the world become increasingly
Broad Aims: To gain a comprehensive understanding of how root scarce in the next 50 years and as agriculture is forced to use more
metabolism and nutrient uptake change in mycorrhizal and non- marginal land for food and biofuel production, it is essential that
mycorrhizal roots in the field and in the greenhouse when patches we create new types of crop plants that are more tolerant of dry
of nutrients are encountered. conditions. Modifications that affect root structure and function
Background: This project brings together the disciplines of plant could potentially reduce plant water usage thereby increasing water
genomics, physiology and ecology. Our team is using the most use efficiency. Such modifications may also reduce the uptake of
modern genomics tools to learn more about the molecular details toxic ions to increase tolerance to saline conditions.
of the symbiotic relationships that are established between fungi
Lab Members:
and roots, and how this relationship aids plants in the acquisition Eliana Gaitan, Ph.D., Postdoctoral Associate
of essential mineral nutrients. Jiyul Jung, Ph.D. Student
Progress: We established a system for studying plant roots that
Min Jung Kim, Ph.D., Postdoctoral Associate
are growing naturally in soil microcosms. In these microcosms
Cathy Kromer, BSc, Administrative Assistant
we have injected ammonium and measured changes in the global
Ellen Marsh, MSc, Senior Research Associate
Renu Pandey, PhD, Visiting Scientist
transcription of genes in the roots in a field and a greenhouse
Daniel Ruzicka, PhD, Postdoctoral Associate
experiment. The changes in transcription will be correlated
Ryoung Shin, Ph.D., Assistant Domain Member
Recent Publications:
Jung, J., Shin, R., Schachtman, D.P., (2009) Ethylene mediates plant response and tolerance to potassium deprivation Plant Cell 21: 607-621
Schachtman, D.P., Goodger, J.Q.D. (2008) Chemical root to shoot signaling under drought Trends in Plant Science 13: 281 – 287
Swarup, K., Benkova, E., Swarup, R., Casimiro, I, Péret. B, Yang, Y., Carrier, D., Nielsen, E., De Smet, I., Vaneste, S., Parry, G., James, N., Calvo, V.,
Ljung, K., Kramer, E.M., Graham, N., Marillonnet, S., Patel, K., Jones, J.D.G., Taylor, C.G., Schachtman, D.P., May, S.T., Sandberg, G., Friml,
J., Kerr, I., Beeckman, T., Laplaze, L. and Bennett, M.J. (2008) The auxin influx carrier LAX3 facilitates lateral root emergence in Arabidopsis,
Nature Cell Biology 10:946 - 954
Spollen, W.G., Tao, W., Balliyodan, B., Chen, K., Hejlek, L.G., Kim, J.J., LeNoble, M.E., Zhu, J., Bohnert, H.J., Henderson, D., Schachtman, D.P.,
Davis, G.E., Springer, G.K., Sharp, R.E., Nguyen, H.T. (2008) Spatial distribution of transcript changes in the maize primary root elongation
zone at low water potential BMC Plant Biology 8:32.
Qi, Z, Hampton, CR, Shin, R, Barkla, BJ, White, PJ, and Schachtman, DP (2008) The high affinity K
+
transporter AtHAK5 plays a physiological
role in planta at very low K
+
concentrations and provides a cesium uptake pathway in Arabidopsis. Journal of Experimental Botany 59: 595-
607.
Alvarez, S, Marsh, EL, Schroeder, SG, Schachtman, DP, (2008) Metabolomic and proteomic changes in the xylem sap of maize under drought.
Plant Cell and Environment 31: 325-40.
Fung, RWM, Gonzalo, M, Fekete, C, Kovacs, LG, He, Y, Marsh, E, McIntyre, LM, Schachtman, DP, Qiu, W, (2008) Transcriptional profiling reveals
novel insights Into powdery mildew-induced defense response in grapevine. Plant Physiology 146:236-249
2008 Scientific Report The Donald Danforth Plant Science Center 17
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