Transcriptome analysis reveals sunflower cytochrome P450 CYP93A1 responses to high salinity treatment at the seedling stage

Sunflower ( Helianthus annuus ) is an important global source of plant lipids and protein for food and other industries. Salinity is an abiotic stress that affects sunflower yield. Although recent studies have revealed that the cytochrome P450 (CYP) 93 family is involved in biotic and abiotic stresses, the relationship between the CYP93A gene and salt stress is not well understood in sunflower. In the present study, we performed transcriptome analysis of a relatively salt-tolerant sunflower variety ‘Xinkui 10’ at the seedling stage under high salinity treatment. Following de novo assembly, 66,426 unigenes were obtained, 45,724 (68.83%) of which were annotated. 5,852 differentially expressed genes (DEGs) were identified 11 distinct clusters in which three main clusters (K1–K3) accounted for 94.39% of DEGs. Mapman analysis showed that CYP450 genes were greatly enriched in cluster K3 and one continuously up-regulated gene, HaCYP93A1 , was identified among 248 common DEGs in the transcriptome of ‘Xinkui 10’. Real-time quantitative RT-PCR (qRT-PCR) analysis indicated that transcript levels of HaCYP93A1 were induced by high salinity and jasmonic acid (JA) in roots. Meanwhile, three JA-biosynthesis genes (allene oxide cyclase 3 [ AOC3 ], lipoxygenase 3 [ LOX3 ], and allene oxide synthase [ AOS ]) in roots were up-regulated under salinity treatment. Moreover, correlation analysis indicated that the expression of HaCYP93A1 was markedly related with the JA-biosynthesis genes. Our results suggested that HaCYP93A1 might be involved in the salt tolerance pathway by regulating JA signaling in sunflower.