Validation of reference genes. To confirm the reliability of selected reference genes, the relative expression profiles of PR3 gene was determined and normalized with the two most stable and two least stable genes. The relative expression levels were calculated by 2 −△△Ct method 49. For each qPCR experiment, three technical replicates were performed for each biological replicate. A one-way analysis of variance (ANOVA) was performed using the PROC GLIMMIX procedures of SAS (version 9.3, SAS institute, Inc., Cary, NC) for each time-point. Fisher's LSD was used for multiple means comparison at the level of α = 0.05.

Background Monilinia blight caused by Monilinia vaccinii-corymbosi (Reade) Honey (M.vc) is a major disease of wild blueberry that can result in severe crop losses in the absence of an integrated disease management programme. The fungus causes blight in the emerging floral and vegetative buds, but the degree of susceptibility varies among the different wild blueberry phenotypes, ranging from the highly susceptible V. a. f. nigrum to the moderately susceptible V. angustifolium and the least susceptible V. myrtilloides. Results The present study evaluated the defense responses of these major phenotypes during their primary infection (floral buds) with M.vc. The temporal expression profiles of PR genes (PR3 and PR4) and the flavonoid pathway structural genes (CHS, ANS, ANR, DFR and FLS) were analysed. The PR3 and PR4 gene expression profiles revealed that V. myrtilloides responded to M.vc infection by activating the expression of both PR genes. V. a. f. nigrum, on the other hand, failed to activate these genes, while V. angustifolium, exhibited an intermediate response. Our study with the flavonoid pathway genes indicated variability in activation of the genes during post-infection time points with ANS and ANR in V. myrtilloides, FLS in V. angustifolium and no response observed in V. a. f. nigrum. Conclusions Altogether, this study highlights that the degree of phenotype susceptibility is associated with the timely activation of host defense responsive genes. Data obtained in this study provided a starting point for a better understanding of the wild blueberry- M. vaccinii-corymbosi pathosystem.

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Botrytis blight is an important disease of wild blueberry [(Vaccinium angustifolium (Va) and V. myrtilloides (Vm))] with variable symptoms in the field due to differences in susceptibility among blueberry phenotypes. Representative blueberry plants of varying phenotypes were inoculated with spores of B. cinerea. The relative expression of pathogenesis-related genes (PR3, PR4), flavonoid biosynthesis genes, and estimation of the concentration of ten phenolic compounds between uninoculated and inoculated samples at different time points were analyzed. Representative plants of six phenotypes (brown stem Va, green stem Va, Va f. nigrum, tall, medium, and short stems of Vm) were collected and studied using qRT-PCR. The expression of targeted genes indicated a response of inoculated plants to B. cinerea at either 12, 24, 48 or 96 h post inoculation (hpi). The maximum expression of PR3 occurred at 24 hpi in all the phenotypes except Va f. nigrum and tall stem Vm. Maximum expression of both PR genes occurred at 12 hpi in Va f. nigrum. Chalcone synthase, flavonol synthase and anthocyanin synthase were suppressed at 12 hpi followed by an upregulation at 24 hpi. The expression of flavonoid pathway genes was phenotype-specific with their regulation patterns showing temporal differences among the phenotypes. Phenolic compound accumulation was temporally regulated at different post-inoculation time points. M-coumaric acid and kaempferol-3-glucoside are the compounds that were increased with B. cinerea inoculation. Results from this study suggest that the expression of PR and flavonoid genes, and the accumulation of phenolic compounds associated with B. cinerea infection could be phenotype specific. This study may provide a starting point for understanding and determining the mechanisms governing the wild blueberry-B. cinerea pathosystem.

Genetic diversity among ten small cardamom accessions having variability in yield traits was investigated using inter simple sequence repeat markers (ISSR). A better understanding of the variability in yield is essential for the proper utilization of genotypes in breeding programmes. Of the 10 primers analysed, 5 reported polymorphisms and generated a total of 47 scorable loci, of which 32 were polymorphic revealing 68% polymorphism. The molecular weight of the fragments ranged from 200-1100 bp. Specific banding pattern was observed in high yielding group using ISSR7 (800bp) and with ISSR 3 (800bp) for low yielding group. Genetic diversity analysis within and among the two groups showed maximum diversity in high yielding varieties based on the values of Nei’ s genetic diversity (h) and Shannon’s informative index (I). Dendrogram based on Jaccard’s similarity coefficients were generated based on an average linkage algorithm (UPGMA) using marker data. Clear grouping of the ten accessions of small cardamom into two clusters was observed. These results suggested that ISSR markers could efficiently differentiate the small cardamom genotypes based on yield and can be useful for future cardamom improvement programmes.