BSR-Seq Analysis Provides Insights into Cold Stress in Actinidia Arguta F1 Populations

Abstract BackgroundThe freezing injury, which is one of the important abiotic stresses in horticultural crops, can influences the growth and development and the production area of kiwifruit (Actinidia Lind1). Actinidia arguta has excellent cold resistance in Actinidia species, but knowledge relevant to molecular mechanisms is still limited so far. Understanding the mechanism of cold resistance in kiwifruit is important for cold-resistant breeding. ResultsIn our study, a cross of ‘Ruby-3’בKuilv’ male was built for the A. arguta hardiness study, and 20 cold-tolerant and 20 cold-sensitive populations were selected from 492 populations according to LT50. Then, we performed Bulked segregant RNA-seq combined with single-molecule real-time sequencing to identify differentially expressed genes with cold hardiness. We found that the content of soluble sucrose and the activity of β-amylase were higher in the cold tolerant population pool than in the cold sensitive population pool. Upon -30°C low temperature treatment, 126 differentially expressed genes were found, and 59 genes were upregulated and 67 genes were downregulated when comparing the tolerant and sensitive pools, respectively. KEGG pathway analysis showed that the DEGs mainly belonged to starch and sucrose metabolism and amino sugar and nucleotide sugar metabolism. There were main 10 key enzyme encoding genes and two regulatory genes were up regulated in tolerant pool, regulated genes of CBF pathway were found to be different expressed, especially, 14-3-3 gene was down regulated and EBF gene was up regulated. To validate the BSR-Seq results, 24 DEGs were determined by qRT-PCR, and the results were consistent with BSR-Seq.ConclusionOur research provides valuable insights into the mechanism related to cold resistance in Actinidia and identified potential genes that are important for cold resistance in kiwifruit.