The relationship with the environment is fundamental to the biology of
all organisms, and especially to plants. Our research group investigates key
aspects of this relationship, focusing on the ways in which environment changes
plant biology over a wide range of timescales: from the short-term
physiological adaptation of individual plants to fluctuating environments, to
the long-term effects of environment on plant evolution. We also have
particular interests in how plants coordinate the regulation of their growth
with their acquisition of carbon and mineral nutrient resources from the
environment. These particular interests arise from our previous world-leading
work on the gibberellin-DELLA mechanism and our discovery of the mechanisms via
which ‘green revolution’ crop varieties are altered in this coordination (see
below). Our approaches are unified by the use of genetics, with a strong
emphasis on whole-genome sequencing, and we use both model and crop plant
systems (Arabidopsis thaliana, rice and wheat) appropriate to
particular research questions. Our coordinated interests cover both fundamental
questions (e.g., How does mutation contribute to plant evolution?) and
practical outcomes (e.g., Can we improve the nutrient use efficiency (NUE) or
soil-salinity tolerance of crop plants?). Specific interests are outlined below
(see Current Projects).
Previously (until August 2007) our research group was located at the
John Innes Centre, Norwich, and focused on the genetics of plant growth
regulation by the phytohormone gibberellin. We revealed the nature and
biological properties of the gibberellin-DELLA mechanism (the mechanism via
which gibberellin promotes plant growth), and showed that a variant form of
this mechanism causes the dwarfism characteristic of the high-yielding wheat
varieties of the 'green revolution'. We also showed that the gibberellin-DELLA
mechanism integrates the effects of multiple environmental signals, and that it
provides plants with the capacity to regulate their growth in response to environmental
change. We also determined how the gibberellin-DELLA mechanism evolved during
land-plant evolution, showing how the modern angiosperm mechanism was derived
by a series of steps from precursor components present in the earliest
We welcome contacts from prospective graduate students and postdoctoral
There are currently three interrelated areas of research in the lab:
Mutation and Evolution
We are interested in the role that de
novo DNA sequence mutation plays in evolution, and in determining the
extent to which the environment influences this process. This project involves
whole-genome studies of A. thaliana. We initially developed
(in collaboration with Prof. Richard Mott at the University of Oxford Wellcome
Trust Centre for Human Genetics) robust methods for the identification of de
novo DNA sequence mutations in ‘short-read’ whole genome DNA
sequencing datasets. We are now amongst the world leaders in de
novo mutation detection, and are applying our methods to understand
how de novo mutations arise. For example, although it has long
been known that exposure to environmental fast-neutron (FN) irradiation is
mutagenic, the genome-wide effects of fast-neutron irradiation were poorly understood.
We have recently shown that, in contrast to what was previously thought, FN
exposure causes more base substitution mutations than deletion mutations, and
that these substitutions exhibit a characteristic molecular mutational spectrum
(a reflection of the different frequencies of specific transition and
transversion mutations) that is very different from that exhibited by mutations
arising spontaneously in control plants (Belfield et al., 2012).
In further studies, we have investigated the fascinating
phenomenon of plant somaclonal variation. When whole plants are regenerated
from cells grown in in vitro cell culture conditions, these
plants often exhibit high frequencies of heritable phenotypic variation, a
phenomenon known as somaclonal variation. Until recently, the underlying causes
of somaclonal variation were poorly understood. We have advanced understanding
of this phenomenon by showing that base substitution mutation is a major cause
of somaclonal variation, and that the molecular mutational spectrum of
mutations arising during plant regeneration is again very different from that
of mutations arising spontaneously in control plants (Jiang et al.,
More recently, we have extended these studies by
experimental analysis of the effects of environment on genome-wide
inherited de novo mutations in plants. Our recent analysis of
the effects of growing plants in stressful high-salinity soil environments has
shown that the environment influences both rate and molecular spectrum of
accumulated mutations, and also changes the patterns of inherited epigenetic
changes in cytosine methylation status (Jiang et al., 2014).
Our studies in the area of Mutation and
Evolution are unified by the concept that an understanding of the effects
of the natural environment on the accumulation of mutations is necessary for a
full understanding of how evolution works.
Towards Molecular Breeding of 21st
Century ‘Super-Green Revolution’ Crop Varieties
Ensuring future global food security is a major
humanitarian challenge. The needs of the around 9 billion people expected by
2050 require a two-fold increase in crop productivity. This increase must be
achieved with minimal environmental damage. In the second half of the 20th
century, the introduction of high-yielding cereal ‘Green Revolution’ Varieties
(GReVs) began progressive crop productivity increases. However, these increases
have recently plateaued. Furthermore, GReVs have low soil mineral nutrient use
efficiency (NUE), and are dependent for high yield upon environmentally
unsustainable fertilizer applications.
A new approach to yield breeding is essential: the
molecular breeding of 21st century ‘Super-Green Revolution’ Crop
Varieties (SuGReVs). We previously discovered the molecular identity of the Rht ‘green revolution’ gene variants of
wheat GReVs, showing that variant forms of the gibberellin-DELLA mechanism are
crucial to yield. These previous insights give us a unique vision for the
development of SuGReVs. Our vision builds upon new understanding of the biology
of GReVs, and of plant mineral nutrient uptake and assimilation. It exploits
revolutionary ‘genome-editing’ technologies, and extant natural genetic
We are currently seeking funding for this project.
In summary, we will use
state-of-the-art molecular breeding techniques to transform GReVs into SuGReVs.
These SuGReVs will produce increased grain yields with reduced fertiliser
input, thus promoting future global food security and reducing environmental
Plant Responses to Environmental
We are working on plant salt-stress responses as a
fundamental model of how plants respond physiologically to the challenge of
stressful environments, and because salt-stress is a major global threat to the
yields of crop plants. Our work in this area involves mutational investigations
with A. thaliana, with a special focus on the responses of plants
to high-salinity soils. We have selected mutants exhibiting either increased
resistance or increased sensitivity to growth on saline soils. These studies
have enabled substantial advance in understanding, because previous studies
of A. thaliana salt-stress responses have mostly been
conducted in low-transpiration petri-dish environments. In contrast, our
studies more closely reflect the reality of plants growing in the wild or in
the field, in which the transpiration stream is a major conduit of water and
salts through the xylem vasculature from the root to the shoot of plants. In
collaboration with Prof. Andrew Smith (University of Oxford Department of Plant
Sciences) we have shown that levels of reactive oxygen species (ROS) in the
region of the root vasculature regulate the sodium (Na) content of xylem sap,
and that these ROS levels are themselves controlled by Na sensitive regulation
of the activity of a specific respiratory burst oxidase enzyme (encoded by the
gene AtrbohF) catalyzing ROS production. Thus we have discovered a
ROS-regulated mechanism for regulation of root-to-shoot delivery of soil Na, a
discovery that has major implications both for our understanding of how plants
maintain internal ionic homeostasis, and for the hugely important goal of
improving the salinity-tolerance of diverse agricultural crops (Jiang et
al., 2012; Jiang et al., 2013).
Our novel discoveries of previously unknown
mechanisms via which plants achieve physiological adaptation to a saline-soil
environment have important practical implications. Soil salinity is a major
factor limiting agricultural production, and affects an estimated ~62 million
hectares of cultivated land world-wide. Furthermore, the global area of
salinized cultivated land is rapidly increasing due to the widespread use of
irrigation systems, thus threatening global food security. There is therefore
an urgent need to understand plant soil-salinity tolerance mechanisms, and to
identify genes conferring tolerance. Our elucidation of the mechanisms of
transpiration-dependent salt tolerance has particular relevance to crops
growing in field environments, and to the need to improve both salinity
tolerance and water-use efficiency in agriculture.
Our work (1997-2012) has
been funded by the BBSRC, The Gatsby Charitable Foundation, the European Union
and the King Abdullah University of Science and Technology.
Yasumura, Y., Crumpton-Taylor, M., Fuentes, S. & Harberd, N. P.
acquisition of the gibberellin-DELLA growth-regulatory mechanism during
land-plant evolution. Current Biology 17, 1225-1230.
Achard, P., Baghour, M., Chapple, A., Hedden, P., Van Der Straeten, D.,
Genschik, P., Moritz, T. & Harberd, N. P. (2007). The plant stress hormone ethylene controls floral transition via
DELLA-dependent regulation of floral meristem-identity genes. Proceedings of
the National Academy of Sciences of the United States of America 104,
Jiang, C., Gao, X., Liao, L., Harberd, N.P. & Fu, X. (2007). Phosphate starvation root architecture and anthocyanin
accumulation responses are modulated by the gibberellin-DELLA signaling pathway
in Arabidopsis. Plant Physiology 145, 1460-1470.
Achard, P., Liao, L., Jiang, C., Desnos, T., Bartlett, J., Fu, X. & Harberd,
N. P. (2007). DELLAs contribute to
plant photomorphogenesis. Plant Physiology 143, 1163-1172.
Harberd, N. (2006). Seed to Seed:
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Achard, P., Cheng, H., De Grauwe, L., Decat, J., Schoutteten, H., Moritz, T.,
Van Der Straeten, D., Peng, J. & Harberd, N. P. (2006). Integration of plant responses to environmentally
activated phytohormonal signals. Science 311, 91-94.
Sablowski, R. & Harberd, N. P. (2005). Plant
genes on steroids. Science 307, 1569-1570.
Alvey, L. & Harberd, N. P. (2005). DELLA
proteins: integrators of multiple plant growth regulatory inputs? Physiologia
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Vriezen, W. H., Achard, P., Harberd, N. P. & Van Der Straeten, D.
(2004).Ethylene-mediated enhancement of
apical hook formation in etiolated Arabidopsis thaliana seedlings is
gibberellin dependent. Plant Journal 37, 505-516.
Fu, X., Richards, D. E., Fleck, B., Xie, D., Burton, N. & Harberd, N. P.
(2004).The Arabidopsis mutant sleepy1gar2-1
protein promotes plant growth by increasing the affinity of the SCFSLY1 E3
ubiquitin ligase for DELLA protein substrates. Plant Cell 16, 1406-1418.
Cheng, H., Qin, L., Lee, S., Fu, X., Richards, D. E., Cao, D., Luo, D.,
Harberd, N. P. & Peng, J. (2004). Gibberellin
regulates Arabidopsis floral development via suppression of DELLA protein
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Achard, P., Herr, A., Baulcombe, D. C. & Harberd, N. P. (2004). Modulation of floral development by a
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Petty, L. M., Harberd, N. P., Carre, I. A., Thomas, B. & Jackson, S. D.
(2003).Expression of the Arabidopsis gai
gene under its own promoter causes a reduction in plant height in chrysanthemum
by attenuation of the gibberellin response. Plant Science 164, 175-182.
Hynes, L. W., Peng, J., Richards, D. E. & Harberd, N. P. (2003). Transgenic expression of the Arabidopsis DELLA
proteins GAI and gai confers altered gibberellin response in tobacco.
Transgenic Research 12, 707-714.
Harberd, N. P. (2003). Relieving DELLA
restraint. Science 299, 1853-1854.
Fu, X. & Harberd, N. P. (2003). Auxin
promotes Arabidopsis root growth by modulating gibberellin response. Nature
Ait-ali, T., Rands, C. & Harberd, N. P. (2003). Flexible control of plant architecture and yield via
switchable expression of Arabidopsis gai. Plant Biotechnology journal 1,
Achard, P., Vriezen, W. H., Van Der Straeten, D. & Harberd, N. P.
(2003).Ethylene regulates arabidopsis
development via the modulation of DELLA protein growth repressor function.
Plant Cell 15, 2816-2825.
Peng, J., Richards, D. E., Moritz, T., Ezura, H., Carol, P. & Harberd,
N. P. (2002). Molecular and
physiological characterization of Arabidopsis GAI alleles obtained in targeted
Ds-tagging experiments. Planta 214, 591-596.
Peng, J. & Harberd, N. P. (2002). The
role of GA-mediated signalling in the control of seed germination. Current
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Lee, S., Cheng, H., King, K. E., Wang, W., He, Y., Hussain, A., Lo, J.,
Harberd, N. P. & Peng, J. (2002). Gibberellin
regulates Arabidopsis seed germination via RGL2, a GAI/RGA-like gene whose
expression is up-regulated following imbibition. Genes & Development 16,
Fu, X., Richards, D. E., Ait-Ali, T., Hynes, L. W., Ougham, H., Peng, J.
& Harberd, N. P. (2002).
Gibberellin-mediated proteasome-dependent degradation of the barley DELLA
protein SLN1 repressor. Plant Cell 14, 3191-3200.
Fleck, B. & Harberd, N. P. (2002). Evidence that the Arabidopsis nuclear gibberellin signalling protein GAI
is not destabilised by gibberellin. Plant Journal 32, 935-947.
Richards, D. E., King, K. E., Ait-Ali, T. & Harberd, N. P. (2001). How gibberellin regulates plant growth and
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King, K. E., Moritz, T. & Harberd, N. P. (2001). Gibberellins are not required for normal stem growth
in Arabidopsis thaliana in the absence of GAI and RGA. Genetics 159, 767-776.
Fu, X., Sudhakar, D., Peng, J., Richards, D. E., Christou, P. & Harberd,
N. P. (2001). Expression of Arabidopsis
GAI in transgenic rice represses multiple gibberellin responses. Plant Cell 13,
Desnos, T., Puente, P., Whitelam, G. C. & Harberd, N. P. (2001). FHY1: a phytochrome A-specific signal transducer.
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Richards, D. E., Peng, J. & Harberd, N. P. (2000). Plant GRAS and metazoan STATs: one family? Bioessays
Collett, C. E., Harberd, N. P. & Leyser, O. (2000). Hormonal interactions in the control of
Arabidopsis hypocotyl elongation. Plant Physiology 124, 553-562.
Peng, J., Richards, D. E., Moritz, T., Cano-Delgado, A. & Harberd, N. P.
(1999a). Extragenic suppressors of the
Arabidopsis gai mutation alter the dose-response relationship of diverse
gibberellin responses. Plant Physiology 119, 1199-1208.
Peng, J., Richards, D. E., Hartley, N. M., Murphy, G. P., Devos, K. M.,
Flintham, J. E., Beales, J., Fish, L. J., Worland, A. J., Pelica, F., Sudhakar,
D., Christou, P., Snape, J. W., Gale, M. D. & Harberd, N. P. (1999b). 'Green revolution' genes encode mutant
gibberellin response modulators. Nature 400, 256-261.
Ezura H., Higashi, K. & Harberd, N. P. (1999). Phytochrome B influences in-vitro shoot morphogenesis
in Arabidopsis thaliana (L.) Heyhn. Plant Biotechnology 16, 279-284.
Cowling, R. J. & Harberd, N. P. (1999). Gibberellins control Arabidopsis hypocotyl growth via regulation of
cellular elongation. Journal of Experimental Botany 50, 1351-1357.
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Richards, D. E. (1998). Gibberellin:
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Cowling, R. J., Kamiya, Y., Seto, H. & Harberd, N. P. (1998). Gibberellin dose-response regulation of GA4 gene
transcript levels in Arabidopsis. Plant Physiology 117, 1195-1203.
Peng, J. & Harberd, N. P. (1997). Transposon-associated
somatic gai-loss sectors in Arabidopsis. Plant Science 130, 181-188.
Peng, J. & Harberd, N. P. (1997). Gibberellin
deficiency and response mutations suppress the stem elongation phenotype of
phytochrome-deficient mutants of Arabidopsis. Plant Physiology 113, 1051-1058.
Peng, J., Carol, P., Richards, D. E., King, K. E., Cowling, R. J., Murphy,
G. P. & Harberd, N. P. (1997). The
Arabidopsis GAI gene defines a signaling pathway that negatively regulates
gibberellin responses. Genes and Development 11, 3194-3205.
Prof. David Baulcombe, University of Cambridge.
Prof. Dominique Van Der Straeten, Ghent, Belgium.
Prof. Ian King, University of Nottingham.
Dr. Ioannis Ragoussis, WTCHG, Oxford.
Prof. Jinrong Peng, ICMB, Singapore.
Prof. John Snape, JIC, Norwich.
Prof. Jonathan Jones, Sainsbury Lab, Norwich.
Dr. Margaret Boulton, JIC, Norwich.
Prof. Ottoline Leyser, Sainsbury Laboratory, Cambridge University.
Prof. Pascal Genschik, IBMP, Strasbourg, France.
Dr. Patrick Achard, IBMP, Strasbourg, France.
Prof. Richard Mott, WTCHG, Oxford.
Mr. Steve Reader, JIC, Norwich.
Dr. Thomas Moritz, Umeå, Sweden.
Dr. Toshi Foster, HortResearch, New Zealand.
Dr. Xiangdong Fu, Beijing, China.
Prof. Yuji Kamiya, RIKEN, Japan.