Plant growth regulator extracts from seaweeds promote plant growth and confer drought tolerance in canola (Brassica napus)

ABSTRACT

Brassica napus, commonly known as canola, is an important oilseed crop in Canada contributing over $29.9 billion CAD to the Canadian economy annually. A major challenge facing Canadian canola is drought, which has become increasingly prevalent in recent years due to the changing climate. Research investigating novel agronomic techniques in mitigating drought is key to securing yields and sustainability in canola and other crops. One such technique is the use of bio-stimulant sprays to help offset biotic and abiotic stresses in plants through promoting stand establishment. Previous studies have shown that the application of seaweed extracts as bio-stimulant sprays to Brassicaceae has been successful in improving plant growth and development along with stress tolerance. However, this method has yet to be tested on canola. The organic nutrients that are waste products from processed seaweed help stimulate plant growth, yielding higher quality plants as a result. In association with Le Groupe Roullier, this study demonstrates that the Roullier extracts (RE) help increase plant growth characteristics and drought tolerance in canola when sprayed 3 times over a 3-week period. A high yielding but drought sensitive mutant of canola, d14 (developed through gene editing) was used for drought assays after 8 weeks of growth and where water was withheld for 6 days. Application of the REs prior to drought resulted in plants having enhanced survival rate and improved biomass retention indicating high drought tolerance. Subsequent RNA sequencing and gene ontological term analysis performed using RE treated plants in triplicates, revealed substantial levels of differential expression of growth-related genes along with stress-related genes. These REs elicited responses in plants that had previously only been achieved through gene editing and transgenic methodologies. Using bio-stimulant sprays provides a novel platform to promote beneficial agronomic traits, independent of genetic manipulation.

KEYWORDS:

• Seaweed extract
• biostimulant
• growth and development
• drought
• transcriptomics

Acknowledgments

Funding for this research project was provided by Timac Agro and Agro Innovation International.

Disclosure statement

No potential conflict of interest was reported by the author(s).

List of abbreviations

DEGs	=	Differentially expressed genes
GO	=	Gene ontological
KEGG	=	Kyoto Encyclopedia of Genes and Genomes
PlantGSAD	=	Plant Gene Set Annotation Database
RE	=	Roullier extracts

Additional information

Funding

The work was supported by the Mondial de l’Innovation Roullier - TIMAC AGRO, Saint-Malo, France Agro Innovation International, Centre Mondial de l’Innovation Roullier - TIMAC AGRO, Saint-Malo, France .