Molecular and Developmental Genetics Group

Normal (wild-type) Arabadopsis flowers are shown at the centre and loss of function "bp" mutants are shown in the corners.

This group's work focuses on gene discovery and elucidation of selected developmental and metabolic processes in plants. The approaches employed toward this objective and the associated expertise include genomics, molecular and biochemical technologies of various sorts (targeted libraries, ESTs, microarrays, proteomics, gene tagging, gene activation and gene silencing, promoter discovery, and genetic modifier screens, metabolic engineering).

Genetic tools for plant improvement

Promoters

Precise genetic modifications require not only specific genes but also regulatory elements that afford precision with respect to location, timing, and magnitude of transgene expression. A key element in this regard is promoter, and the group has established a collection of various promoters, and sources of promoter libraries from various species of Brassica (canola/rapeseed), Sinapis alba (white mustard), Nicotiana tabacum (tobacco) and Arabidopsis thaliana (thale cress). The promoters that have been isolated include those active in xylem and phloem that serve as transport channels in plants; promoters active in reproductive tissues such as pollen and flowers; and promoters that cause gene expression in response to injury (such as wounding by a predator). Some have also been found that are active during various stages of seed development in canola.

Contact:
Dr. Gopalan Selvaraj at Gopalan.Selvaraj@nrc-cnrc.gc.ca
Phone: (306) 975-5577.
Dr. Raju Datla at Raju.Datla@nrc-cnrc.gc.ca
Phone: (306) 975-5267.

Engineering plant metobolism

Phenylpropanoid metabolism

Plants use the phenylpropanoid pathway to produce a vast array of secondary metabolites – products that are finding uses in nutrition, medicine and industry. Understanding this pathway allows better control of what it produces. An example is the reduction of sinapine levels in canola meal. Some hens produce off-flavoured eggs when fed on canola meal, and the sinapine content of canola meal is the culprit. In order to make canola meal more acceptable to the poultry feed industry and to make meal more valuable in general, the group has reduced sinapine levels by approximately 80%. An extension of the work on phenylpropanoids is the discovery of metabolic steps and associated genes involved in biosynthesis of nutraceutical compounds for animal and human consumption. This work is in progress.

Contact: Dr. Gopalan Selvaraj at Gopalan.Selvaraj@nrc-cnrc.gc.ca
Phone: (306) 975-5577.

How plants develop

Inflorescence architecture

Knowledge of flower development has important applications in plant improvement. Homeobox genes control very basic plant functions, such as flower, embryo and seed development. One example is the Brevipedicillus (BP) gene in canola (Brassica napus).

BP helps regulate how flowers form in Arabidopsis thaliana (thale cress), which belongs to same family as canola. Mutants of the gene produce compact, downward-pointing flowers, unlike the larger, erect blooms of a normal plant. When applied to canola, this mutation should help reduce pod shattering and improve the harvested yield of canola seeds.

Another research target is AtRBP, one of a number of genes that controls flowering time and development. Work is being done to understand its molecular and genetic structure.

Understanding of these and related regulatory genes will be used in plant breeding, horticulture and in the management of crop pests.

Contact: Dr. Raju Datla at Raju.Datla@nrc-cnrc.gc.ca
Phone: (306) 975-5267.

Controlling wheat fertility

RAFTIN

Wheat contains a protein called RAFTIN, associated with enigmatic structures called "Ubisch bodies." While it is uncertain what these structures do, they are almost always associated with the secretory tapetum that nourishes developing pollen grains. PBI researchers have demonstrated that RAFTIN is essential in the maturation of pollen grains. RAFTIN-silenced lines show male sterility, and this can have applications in producing hybrid seeds.

Flowering genes

The major Canadian crop products are all seed-oriented. Productivity in this regard is controlled by transition at an appropriate time from vegetative growth to flowering. The group has identified in wheat a gene that potentially controls flowering. The recent studies have shown that wheat differs from other plants in having an unprecedented arsenal of this particular gene in numerous copies. Further work on how wheat orchestrates its flowering is underway.

Contact: Dr. Gopalan Selvaraj at Gopalan.Selvaraj@nrc-cnrc.gc.ca
Phone: (306) 975-5577.

A cornerstone of plant development

NMT – An ubiquitous enzyme

N-myristoyltransferase (NMT) is an essential enzyme that affects a broad range of processes in animals, plants, and fungi. The group was the first to identify the NMT gene in plants. Modifying NMT levels alter several plant functions, from germination and root growth to flowering and meristem function. Precise manipulation of NMT with selected promoter elements is anticipated to alter plant development and metabolism in many interesting ways. This should allow for engineering desirable plant form and function.

Contact: Dr. Raju Datla at Raju.Datla@nrc-cnrc.gc.ca
Phone: (306) 975-5267.

Genes associated with early phases of seed development

Gene discovery

As a part of a large project involving other PBI groups, the MDG group has generated over 25,000 expressed sequence tags (ESTs) from various phases of seed development. Majority of these are from post-fertilization embryos isolated from young seeds. In combination with genes expressed elsewhere in the developing seeds, these provide a rich source of genes for functional characterization and further manipulation.