Page 280 - PC2019 Program & Proceedings

PLANT CANADA 2019

P133. Seasonal changes in photosynthesis, transpiration and chlorophyll levels in American
Sweetgum (Liquidambar styraciflua) and Hungarian Oak (Quercus frainetto) and Japanese Katsura
(Cercidiphyllum japonicum)
Singh, S.; G. Bhatt; A. Jimenez
University of British Columbia, Canada

The environmental aspect of sustainability has become an increasingly important topic due to its impact
on climate change and carbon sequestration processes. A diverse variety of tree species act as a living
laboratory that can be used to investigate the effects of environmental factors on the growth,
development, and physiology of plants. Therefore, it is important to analyze the effects of seasonal
changes and environmental factors on the relative efficiency of various plant species in carbon
sequestration, transpiration, and leaf chlorophyll levels. In this study, we analyzed the photosynthesis and
transpiration rates, protein and chlorophyll levels in the leaves of American Sweetgum, Hungarian Oak
and Japanese Katsura trees during 2018-2019. The results showed that the Hungarian Oak had the highest
photosynthesis rate and that the stressed Japanese Katsura had the highest chlorophyll level while the
American Sweetgum had the lowest chlorophyll level among the three species. The transpiration rates
were relatively similar among the species. In addition, the soil compaction stress reduced the rates of
photosynthesis in Japanese Oak trees. The relative effects of the developmental and environmental
changes on photosynthesis and transpiration rates and leaf protein and chlorophyll levels in these species
will be discussed.

Santokh Singh (santokh.singh@botany.ubc.ca)

TOPIC 14: Entomology and Pest Management (Posters P134-P135)

P134. Plastid transformation of Micro-tom tomato for RNAi interference in insects
2
1
1
3
Kaplanoglu, E. ; I. Kolotilin ; R. Menassa ; C. Donly
1 Agriculture and Agri-Food Canada
2 Scattered Gold Biotechnology Inc.
3 Government of Canada

RNA interference (RNAi) is used by eukaryotic organisms, including plants and arthropods, as a gene
regulation and defense mechanism. It is also a promising tool for crop protection since it can be used to
selectively silence insect genes essential for survival. One strategy to exploit the insect RNAi pathway for
insect control is to develop plants that produce double-stranded RNA (dsRNA), the effector that activates
the RNAi pathway, specific for insect genes. For optimum potency, dsRNA can be produced in plastids of
plants since they lack intrinsic RNAi processing machinery, thus allowing maximum accumulation of
intact dsRNA. Although plastid transformation of plants holds great promise for insect control, the
feeding behavior of target insects also needs to be considered, as this affects insect uptake of plastids. In
this study, we produced transplastomic Micro-Tom tomato plants expressing dsRNA for a highly
conserved insect gene, v-ATPaseA. We then fed these plants to several insect species from different
Orders that use either leaf-chewing, lacerate-and-flush, or sap-sucking mechanisms to feed. We show that
conserved gene sequences can be used to silence genes in multiple insect species through plastid
transformation. We also found that only insects feeding through leaf-chewing and lacerate-and-flush
mechanisms were susceptible to RNAi when dsRNA is produced in plant plastids.

Emine Kaplanoglu (emine.kaplanoglu@canada.ca)

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