Zheng Lab: Nutrient Balance Signaling Networks in Plants
PI: Zhi-Liang Zheng (PhD, 1999, Ohio State
University)
Associate Professor
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)
Too drought-stressed to sustain …? Enjoy the
Grand Canyon in all its majesty! (Dr. Z-L Zheng, 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 list of
speakers and directions, click the PDF file 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.
● Xin Z, Wang
A, Yang G, Gao P and Zheng Z-L (2009)
The Arabidopsis A4
subfamily of lectin receptor kinases
negatively regulates abscisic acid response in seed
germination.
Plant Physiology 149: 434-444 (Epub
2008 Nov 5) [pdf]
[Full-text
link – Open Access Article]
●
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]