Study on differential expression of HaRIC-B gene and MYB-related transcription factor in sunflower-Sclerotinia pathosystem

Basal stem rot caused by Sclerotinia sclerotiorum is considered the most important fungal disease of sunflower in Iran. Application of resistant genotypes is one of economic strategies for the disease management. Recently, in association mapping for resistance to sclerotinia rot disease in sunflower, a significant relationship has been observed between the lower Sclerotinia-induced necrosis and HaRIC_B gene expression. On the other hand, expression of defense genes is highly regulated by transcription factors. In this study, using real time PCR technique, the expression level of HaRIC_B gene and MYB-related transcription factor were studied in partial resistant (LC1064C/ 8*A) and susceptible (SDR19) lines of sunflower inoculated with the S. sclerotiorum isolate A37. In studying the expression pattern of HaRIC_B gene in two lines, it was seen that the expression pattern in the LC1064C/8*A line was increased regularly from one sampling time to another and the expression rate at any time was more in LC1064C/8*A line than SDR19. Comparison of HaRIC_B gene expression and MYB-related transcription factor revealed a reasonable relationship between the expression level of both genes, especially in the LC1064C/8*A ine. This finding highlight the possible major role of MYB-related transcription factor in stimulating HaRIC_B gene expression and consequently inducing resistance to Sclerotinia in sunflower which, of course, needs further investigation. By confirming the resistance of the LC1064C/8*A line to Sclerotinia at the molecular level, this line could potentially be used in the production of resistant hybrid cultivars in conventional plant breeding programs.