Prolonged water limitation in B. napus restricts growth but maintains photosynthesis through genotype specific time-of-day changes in transcriptomes and sulfur-related metabolomes

ABSTRACT: Water availability is a major determinant of crop production and rising temperatures from climate change is leading to more extreme droughts. To maximize the impact of irrigation on crop yields, we need to develop varieties that are more tolerant to water limited conditions. We aimed to determine how diverse crop types of the allopolyploid Brassica napus, a species that contains the economically important canola oilseed crop, respond to prolonged water limitation. We exposed plants to an 80% reduction in water and assessed growth and color on a high throughput phenotyping system over four weeks and ended the experiment with tissue collection for a time course transcriptomic study. We found an overall reduction in growth across cultivars but to various degrees. The transcriptome analysis did not reveal strong indicators of abiotic stress suggesting that the cultivars had adjusted to the water limited conditions. However, we found significant genotype-specific changes in time-of-day regulation of photosynthesis, carbohydrate metabolism, and sulfur metabolism. Interestingly, there was extensive variation in which paralogs responded to water limitation across crop types that could be due to rearrangements of regulatory regions in these allopolyploid lines. Follow up experiments on select cultivars confirmed that plants maintained photosynthetic health during the prolonged water limitation while slowing growth. In two cultivars examined, we found significant time-of-day changes in levels of glucosinolates, sulfur and nitrogen rich specialized metabolites, consistent with the transcriptomic responses. These results suggest that these lines are adjusting their sulfur and nitrogen stores under water limited conditions through distinct time-of-day regulation.

ORGANISM(S): Brassica napus

PROVIDER: GSE261928 | GEO | 2025/03/05

REPOSITORIES: GEO