Effects of exogenous IBA on antioxidant property and IAA biosynthesis pathway in cuttings of Ficus carica

Abstract

Abstract [Objective] Exploring the effects of suitable concentrations of indole butyric acid (IBA) on rooting and sprouting as well as on antioxidant property and gene expression related to growth hormone biosynthesis pathway of fig(Ficus carica L.) cuttings may provide theoretical basis for its application in fig breeding, propagation, promotion, and planting. [Methods] The hard branches of ‘Bojihong’ fig variety were used as cuttings to analyze the effects of IBA treatments (0, 30, 45, 60, 90 mg/L) on the rooting traits and antioxidant properties of the scions, as well as analyzed the transcriptome of axillary buds in the middle part of fig cuttings under 45 mg/L IBA treatment. [Results] (1) The germination and rooting rates of fig spikes reached the maximum at 45 mg/L IBA and differed from other treatments and the control.(2) With the increase of IBA concentrations, the SOD and CAT activities of spikes showed a trend of first decreasing and then increasing, and both were lower than the control at 45 and 60 mg/L IBA, while POD activity was unchanged between the treatment and control. MDA and H2O2 contents in the spikes under IBA treatments were higher than the control, and MDA content in the spikes at 45 mg/L IBA was lower than other treatments. (3) Transcriptome analysis showed that there were 6 879 differentially expressed genes at 45 mg/L IBA. KEGG enrichment showed that there were 10 differential pathways. GO enrichment analysis indicated that the biological processes and molecular functions were the main biological pathways; the genes related to CAT and SOD were enriched in peroxisomal pathway, while the genes related to POD were enriched in phenylpropane biosynthetic pathway. The metabolism-related gene FcGH3 was up-regulated in the IAA biosynthesis pathway, and the genes related to signaling, such as FcAUX1, FcARG7, and FcARF, were down-regulated. [Conclusion] IBA treatment induced the expression of genes encoding antioxidant enzymes and genes involved in IAA biosynthesis pathway of fig spikes, enhanced resistance to stress, and promoted rooting, sprouting, and seedling formation and 45 mg/L IBA had the best effect

Keywords

• fig (ficus carica l.)， cuttings， indole butyric acid (iba)， antioxidant， iaa biosynthesis