Transcriptome analysis of a chilling tolerance strategy in European maize dent germplasm.
Résumé
Maize has become an extensively cultivated crop in high latitudes like Northern Europe thanks to historical improvements of cold tolerance. However, earlier sowing increase the risk of exposure to longer chilling periods, affecting early growth and frequently plant performance and final yield. Understanding how maize responds to chilling periods is therefore a major task to both better understand maize local adaptation and improve agriculture. Here, we evaluated two sister double-haploid dent maize lines sharing 82% of their genome and displaying a contrasted tolerance to chilling. Using an Illumina stranded and paired-end mRNA-seq dataset from leaves of both sister lines grown under control and chilling conditions, we captured the allelic variation consequences at the transcript level. Clustering of differentially expressed gene profiles let us identify 574 genes differentially expressed, 513 and 61 being up- and down-expressed in the chilling-tolerant line compared to the chilling-sensitive line. We then explored how the variation in gene expression contributes to the variation in phenotypic traits. Genes associated with these traits were identified, paving the way for pinpointing candidate genes for chilling tolerance in future follow-up studies.