Zheng Lab: Nutrient Balance Signaling Networks in Plants
PI: Zhi-Liang
Zheng
(PhD, Ohio State University, 1999)
Assistant Professor of Plant Cellular Signaling
Department of Biological
Sciences
Lehman College, City University of New York
250 Bedford Park Blvd. West
Bronx, NY 10468
Graduate School and University Center
365 Fifth Ave.
New York, NY 10016
Office: Davis Hall 107A
Lab: Davis Hall 107
(718) 960-6955 (Office)
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drought-stressed to sustain …? Enjoy the
Grand Canyon in all its majesty! (Summer
2003)
(718)
960-5741 (Lab)
(718) 960-8236 (Fax)
E-mail: zhiliang.zheng@lehman.cuny.edu
Teaching
BIO 238 Genetics (undergraduate level, 4
credits: 2-hr lecture, 4-hr lab)
BIO 501 Special
Topics in Genetics (graduate
level, 4 credits: 4-hr lecture)
New
course to be offered Current Topics
in Cellular Signaling (graduate level, 3 credits: 3-hr lecture)
Biology
Seminar (BIO 450/630/791): For the details
and the directions, please click here!
Research
Plants are non-motile, photoautotrophic organisms and
therefore they must respond and adapt to the constantly changing environments
(such as light, temperature, water, CO2 and nutrients). Nutrient
availability is one of the most critical factors that limit plant growth and
crop yield. Because of the lack of knowledge that governs how much and when
mineral nutrients should be applied to crops, farmers tend to apply excessive
amounts of fertilizers, which in turn negatively impacts ecosystems and
environments. Therefore, in order to improve the nutrient use efficiency and
optimize the application of fertilizers, it is critical to dissect the fine-tuned
but complex nutrient perception and signal transduction networks. Our research
is currently focused on the major nutrients such as carbon (C), nitrogen (N)
and sulfur (S), with the following specific aims:
OSU1-mediated
C/N balance signaling Using a genetic approach, we recently identified a novel
gene (OVERSENSITIVE TO SUGAR1)
involved in C/N balance response in Arabidopsis
thaliana (Gao et al., 2008). Mutations in the OSU1 gene result in the hypersensitivity of the seedlings to the
imbalanced C/N (high C/low N, and low C/high N), but the osu1 mutants respond normally as wild-type under the balanced C/N,
low C/low N and high C/high N (Figure 1). OSU1
encodes a putative AdoMet-dependent methyltransferase. Interestingly, osu1 mutants are allelic to qua2/tsd2,
the cell-adhesion-defective mutants reported by two other groups (Mouille et
al., 2007; Krupkova et al., 2007). This indicates that OSU1/QUA2/TSD2 might
either have distinct substrates in the control of cell adhesion and C/N balance
response or is important in linking cell wall biogenesis and C/N balance
response. We are currently investigating its signaling mechanisms in the C and
N nutrient balance response.
Novel
components in C-N-S cross-talk Through
a C, N and S combinatorial design (Figure 2), we have revealed
that activation of a vacuolar sulphate transporter gene (SULTR4;2) and a putative thioglucosidase gene by sulfur (S)
deficiency is primarily dependent on the C availability which interacts
synergistically with N (Dan et al., 2007). This demonstrates the differential
effects of C, N and S nutrients on gene expression. To understand the
regulatory mechanism, we have taken advantage of this novel nutrient regulatory
pattern to identify nutrient sensing/signaling proteins involved in the C-N-S
cross-talk. Genetic, physiological and molecular approaches will be used to
understand how plants sense the nutrient status and cross-talk to optimize the
opportunity for cellular metabolism, growth and development.
Role of
hormones in nutrient signaling Plant hormones play an important role in
modulating intracellular and intercellular responses to both internal and
external nutrient status. We have shown that auxin, the key hormone in plants,
plays a negative regulatory role in part of sulphate deficiency response (Dan
et al., 2007). Furthermore, abscisic acid (ABA
Control of cytoskeletal organization
in root hair-mediated nutrient uptake and response Root hairs are important for both the
anchorage of the root system to the soil and the uptake of water and nutrients,
although they are not essential for plant growth and development. Root hairs
are long, thin tubular-shaped outgrowths from root epidermal cells called
trichoblasts. Root hair tip growth is one of the few extreme types of highly
dynamic, polarized growth, and has been used as a unique model system for the
study of plant cell polarity. This dynamic process requires the well-coordinated
cytoskeletons, such as actin filaments (AF) and microtubules (MT), to
facilitate active organelle and vesicle transport. Constitutive activation of
ROP2 and other members of ROP GTPases have been shown to disrupt the root hair
tip growth, likely as a result of the alteration in AF and MT organizations. Interestingly,
the tip growth defect caused by the constitutive activation of ROP2 can be
enhanced by increasing concentrations of C (Figure 3), indicating a
link between the cytoskeletal organization and nutrient response. To identify
novel components of the ROP2-regulated MT and AF cross-talk, we have used a forward
genetic approach, together with cell biological and biochemical tools, to
understand how ROP2 and a kinesin called MRH2 act to control the MT
organization and coordinate with AF (Yang et al., 2007).
Recent Publications
For a complete list of publications,
please click here.
* IMPORTANT NOTE: The copyrights for
most of the manuscripts have been transferred to the journals in which they
were published. The full-text PDF versions are displayed on this page only for
the non-commercial purpose of facilitating the rapid dissemination of
scientific results, such as teaching and research.
● Gao P, Xin Z and Zheng Z-L
(2008)
The OSU1/QUA2/TSD2-encoded
putative methyltransferase is a critical modulator of carbon and nitrogen
nutrient balance response in Arabidopsis.
PLoS ONE 3: e1387 [pdf] [Full-text
link – Open Access Article]
● Yang G, Gao P, Zhang H, Huang S and Zheng Z-L (2007)
A mutation in MRH2
kinesin enhances the root hair tip growth defect caused by constitutively
activated ROP2 GTPase in Arabidopsis.
PLoS ONE 2: e1074 [pdf] [Full-text
link – Open Access Article]
● Dan H, Yang
G and Zheng Z-L (2007)
A negative regulatory role for auxin in sulphate deficiency
response in Arabidopsis thaliana.
Plant Molecular Biology 63: 221-235 (Epub 2006 Oct 25) [pdf]
[Supplemental Figures]
● Xin Z, Zhao
Y and Zheng Z-L (2005)
Transcriptome analysis reveals specific modulation of abscisic
acid signaling by ROP10 small GTPase in Arabidopsis.
Plant Physiology 139: 1350-1365 [pdf]
[Supplemental
Data]
Lab Members
Dr. Zeyu Xin, Research Associate: ABA and C/N balance
signaling
Dr. Yu Chen, Visiting Scientist: C/N balance signaling
Hanbin Dan, PhD Student: Sulphate nutrient signaling
Michelle Quiles, Undergraduate Student: Lab assistant
Lab Alumni: Dr. Peng Gao (postdoc, 6/2004-4/2007), Dr. Guohua Yang (postdoc, 3/2005-9/2007)
Lab News
1/2/2008: Two research papers on C/N
nutrient balance signaling and root
hair tip growth signaling published in PLoS
ONE.
8/31/2006: Hanbin and
Guohua’s sulfur nutrient signaling paper accepted by Plant Molecular Biology! Congratulations!