Page 135 - PC2019 Program & Proceedings

PLANT CANADA 2019

S55. A unified DNA assembly platform for plant research and genome editing
1
1
Bircheneder, M. ; M. Parniske ; D. Chiasson 2
1 LMU Munich
2 Saint Mary's University

Assembling composite DNA modules from custom DNA parts has become routine due to recent
technological breakthroughs such as Golden Gate modular cloning. Using Golden Gate, one can
efficiently assemble custom transcription units and piece units together to generate higher-order
assemblies. Although Golden Gate cloning systems have been developed for experimental work in plants,
they are not typically compatible with organisms from other kingdoms. Consequently, a plant molecular
biology laboratory must use multiple cloning strategies to assemble DNA constructs for diverse
experimental assays. To simplify the DNA assembly process and facilitate experiments across kingdoms,
we built a modular cross-kingdom Golden Gate assembly platform. Plasmid backbones, parts, and
cloning procedures are consistent across the platform, streamlining the assembly of complex DNA
constructs. We are using the multi-kingdom (MK) system to characterize genes regulating the nitrogen-
fixation symbiosis in legumes. Currently, we are focused on understanding the role of key transcription
factors controlling rhizobial infection and nodule organogenesis. Modular DNA parts have also been
developed to advance genome editing capabilities in legumes with Cas9 and Cas12a nucleases. Both
nucleases have successfully generated new loss-of-function alleles for essential symbiosis genes. An
overview of the modular cloning platform and its application for genome editing will be presented.

David Chiasson (chiassond@gmail.com)

S56. Integrating perennial forage seed crops in the cropping systems in western Canada:
An agroecological and economic assessment
1
1
Khanal, N. ; R. Azooz ; N. Lupwayi ; J. Otani ; C. Yoder 2
1
1
1 Agriculture and Agri-Food Canada
2 Government of Alberta
Individual crops yield higher when alternated with unrelated species in cropping sequences than when
grown continuously in the same field. Such yield benefits are attributed to various mechanisms including
pest suppression, improved nutrient and water use efficiencies, changes in rhizosphere biology,
allelopathy or soil structure. This presentation reports the results of a cropping sequence study involving
perennial forage seed crops and annual food crops, conducted at Beaverlodge Research Farm in western
Canada. Eight different crop sequences with three different levels of supplemental nitrogen were
evaluated in terms of cropping systems productivity, relative profitability and changes in soil properties
over four years. The results showed that forage seed crops can be integrated as profitable break crops in
the annual cropping sequences with beneficial effects on soil properties. As the prices of forage seeds and
food grains are major determinants of the profitability, prudent choice of cropping sequences can help
stabilize farm income in the face of fluctuating market.

Nityananda Khanal (nityananda.khanal@canada.ca)

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