Determination of Hesperidin and Limonin Levels as Part of the Defense Mechanism of Some Lemon Varieties [Citrus limon （L,） Burm f.] against Mal Secco Disease [Phoma tracheiphila （Petri） Kanc,et Ghik,]

In this paper, it was aimed to identified and quantified hesperidin and limonin compounds using HPLC （High Performance Liquid Chromatography） techniques against to developing of mal secco disease caused by Phoma tracheiphila. Six citrus lemon varieties （Meyer, Kiitdiken, Enterdonato, Yediveren, Sweet lemon and Euroka） were infected by P. tracheiphila and artificial inoculation were applied in vivo conditions. Before and after inoculation, leaf, branch and stem samples were taken from each lemon varieties. The results show that the amount of hesperidin and limonin concentration was increased after the inoculations at various levels based on the lemon cultivars. Various concentrations （1, 5, 10, 25, 50, 75, 100 ppm） of hesperidin and limonin compounds were also tested under in vitro conditions to compare response of P. tracheiphila development. According to the results, hesperidin and limonin compounds play an important role against to P. tracheiphila development and Sweet Lemon variety was found to be the most resistance both observation and HPLC results.

Unravelling lncRNA mediated gene expression as potential mechanism for regulating secondary metabolism in Citrus limon

Plant long non-coding RNAs(lncRNAs)are emerging as important regulators of gene expression through various mechanisms viz.binding to double-stranded DNA(dsDNA),physically targeting mRNAs and also act as microRNA(miRNA)sponges.Characteristic secondary metabolites and their content determine the market value of Citrus plant products for culinary and industrial uses.Though lncRNAs are emerging as important molecular players that regulate secondary metabolites in plants but the roles of lncRNAs are yet unknown for the regulation of secondary metabolites in Citrus limon.In this study,a total of 11814 lncRNAs were identified from four RNA-seq datasets comprising of data from four different tissues of C.limon viz.leaf,bud,fruit and peel.Co-expression analysis of whole set of genes with identified lncRNAs revealed a total of 632 lncRNAs correlating with 5810 genes.Functional annotation of genes correlating with lncRNAs unveiled the association of 379 genes with the biosynthesis of secondary metabolite pathways and among them,36 and 12 genes are from terpenoids and flavonoids metabolism/biosynthesis pathways respectively.Expression correlation analysis unfolded the possible role of 113 lncRNAs in terpenoids metabolism and 29 lncRNAs in the flavonoids metabolic pathway.Seventy nine lncRNAs were predicted to take part in miRNA-mediated gene regulation,out of which 10 lncRNAs were predicted to act as endogenous target mimics(eTMs)for miRNAs and 74 lncRNAs were found to act as miRNA targets.Expression of six predicted lncRNAs and seven correlated genes involved in terpenoids and flavonoids metabolism were validated using semi-quantitative RT-PCR.