Key Result: Fertilizer applications are a significant cost to growers and unpredictable environmental temperatures and precipitation events can make it tough to predict the proper fertilization regimes. This study investigates an alternative solution for canola growers: the potential benefit of endophytic fungus Piriformospora indica on canola growth and yield. Results from the controlled-environment experiment look very promising.
Project title, Principal investigators: “Improving growth and yield of canola with a novel fungal endophyte Piriformospora indica,” Janusz Zwiazek, University of Alberta
Canola is a very resilient plant, but it has high nutrient requirements and is negatively impacted by unpredictable moisture and temperature stresses. Nitrogen (N) and phosphorus (P) fertilizer are also a large part of total crop expenses. New alternatives that could improve plant productivity and robustness while reducing input costs are worth investigating.
Janusz Zwiazek at the University of Alberta studied the effect of fungal endophyte Piriformospora indica on canola growth, yield, nutrient (nitrogen and phosphorus) uptake and resistance to stress from drought, oxygen-deficiency and low soil temperatures. Although no fungi has been able to successfully colonize a Brassicaceae plant until recently, the potential for this fungus to have a positive impact on canola was considered due to earlier studies of P. indica with other agricultural plants, including Arabidopsis.
P. indica is an endophyte that was first discovered in northwest India. It is able to grow in a variety of plant media and has been reported to improve plant survival in unfavourable conditions. While it has shown benefits to some plants, it has also been found to parasitize certain crops in phosphorus-rich soils.
Inoculated canola seedlings (by P. indica fungal plugs or liquid media) were used in the series of studies testing the growth and yield of plants under different N and P levels and levels of drought, flooding and soil temperature.
Inoculating canola plants with P. indica had a number of positive impacts on growth and yield as well as reducing the negative impacts of environmental stresses and reducing demands for nitrogen and phosphorus.
Despite the lack of benefit found when inoculated plants were grown under controlled-environment conditions in sand culture, the fungus did increase the growth and yield of canola by over 50 per cent and reduce demand for N and P when grown in a medium with sufficient carbon. In addition, while the inoculation of canola plants had no impact on drought resistance at N rates of 50 per cent and 100 per cent during the flowering stage, an improvement in drought resistance was reported at five per cent and 25 per cent N rates. Inoculation of canola was not found to impact the fatty acid composition of the seed, except for C18:3 (alpha-linolenic acid), which was lower in the inoculated plants.
With regards to temperature stress, canola inoculated with P. indica was able to tolerate lower temperatures than non-inoculated plants, with growth at 12°C comparable to the growth at 20°C. Presence of the fungal endophyte also reduced the impact of drought, depending on the growth stage. Furthermore, root and shoot biomass was greater in canola plants inoculated with P. indica compared with non-inoculated plants.
Furthermore, the storage of coated seeds for six to 12 months at 4°C had beneficial effects on plant growth. Effectiveness of this inoculation treatment lasted for up to one year for seeds in cold storage, suggesting this inoculation protocol is promising for commercial scale applications and needs to be further tested. These findings provide some justification for further investigation into P. indica for the growth and yield of canola while providing environmental benefits at the same time.