Transcriptome and Physiological Analysis of Rapeseed Tolerance to Post-Flowering Temperature Increase

Area of Science:

• Agricultural Science
• Plant Biology
• Climate Change Adaptation

Background:

• Climate-change-induced temperature fluctuations threaten global crop production, especially in the Southern Hemisphere.
• Rapeseed (Brassica napus) is vulnerable to heat stress, impacting yield and seed quality.
• Understanding molecular responses to heat stress is crucial for developing resilient crop varieties.

Purpose of the Study:

• To investigate the transcriptome and physiological responses of rapeseed to post-flowering heat stress.
• To identify genotype-specific differences in heat tolerance between Lumen and Solar rapeseed cultivars.
• To elucidate the molecular mechanisms of heat stress adaptation in rapeseed siliques and seeds.

Main Methods:

• Field experiments were conducted in Valdivia, Chile, assessing two rapeseed genotypes (Lumen and Solar) under control and heat stress conditions.
• Seed yield and number were quantified, and RNA-sequencing (RNA-seq) was performed on siliques and seeds.
• Hierarchical clustering and gene coexpression network analyses were employed to identify heat-responsive genes and regulatory modules.

Main Results:

• Heat stress significantly reduced seed yield and number, with genotype Solar (28.7% reduction) more affected than Lumen (9.3% reduction).
• Siliques exhibited greater sensitivity to heat stress than seeds, with distinct gene expression patterns related to protein folding and heat response.
• Genotype-specific gene expression was observed in seeds, particularly for genes involved in protein folding and heat response, highlighting adaptive mechanisms.

Conclusions:

• Rapeseed exhibits complex, tissue-specific responses to heat stress, with siliques being more sensitive.
• Protein folding and heat response pathways are key to maintaining rapeseed development and seed quality under high temperatures.
• This research provides insights into molecular mechanisms for breeding climate-resilient rapeseed varieties with improved yield and quality under heat stress.