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Abstract: In Vanilla planifolia pods, development of flavor precursors is dependent on the phenylpropanoid pathway. The distinctive vanilla aroma is produced by numerous phenolic compounds of which vanillin is the most important. Because of the economic importance of vanilla, vanillin biosynthetic pathways have been extensively studied but agreement has not yet been reached on the processes leading to its accumulation. In order to explore the transcriptional control exerted on these pathways, five key phenylpropanoid genes expressed during pod development were identified and their mRNA accumulation profiles were evaluated during pod development and maturation using quantitative real-time PCR. As a prerequisite for expression analysis using qRT-PCR, five potential reference genes were tested, and two genes encoding Actin and EF1 were shown to be the most stable reference genes for accurate normalization during pod development. For the first time, genes encoding a phenylalanine ammonia-lyase (VpPAL1) and a cinnamate 4-hydroxylase (VpC4H1) were identified in vanilla pods and studied during maturation. Among phenylpropanoid genes, differential regulation was observed from 3 to 8 months after pollination. VpPAL1 was gradually up-regulated, reaching the maximum expression level at maturity. In contrast, genes encoding 4HBS, C4H, OMT2 and OMT3 did not show significant increase in expression levels after the fourth month post-pollination. Expression profiling of these key phenylpropanoid genes is also discussed in light of accumulation patterns for key phenolic compounds. Interestingly, VpPAL1 gene expression was shown to be positively correlated to maturation and vanillin accumulation. [Copyright &y& Elsevier]

Species of the genus Coffea accumulate diterpenes of the ent -kaurane family in the endosperm of their seeds, of which cafestol and kahweol are the most abundant. The diterpenes are mainly stored in esterified form with fatty acids, mostly palmitate. In contrast to the numerous studies on their effects on human health and therapeutic applications, nothing was previously known about their biological and ecological role in planta. The antifungal and anti-insect activities of cafestol and cafestol palmitate were thus investigated in this study. Cafestol significantly affected the mycelial growth of five of the six phytopathogenic fungi tested. It also greatly reduced the percentage of pupation of larvae and the pupae and adult masses of one of the two fruit flies tested. By contrast, cafestol palmitate had no significant effect against any of the fungi and insects studied. Using confocal imaging and oil body isolation and analysis, we showed that diterpenes are localized in endosperm oil bodies, suggesting that esterification with fatty acids enables the accumulation of large amounts of diterpenes in a non-toxic form. Diterpene measurements in all organs of seedlings recovered from whole seed germination or embryos isolated from the endosperm showed that diterpenes are transferred from the endosperm to the cotyledons during seedling growth and then distributed to all organs, including the hypocotyl and the root. Collectively, our findings show that coffee diterpenes are broad-spectrum defence compounds that protect not only the seed on the mother plant and in the soil, but also the seedling after germination. [Display omitted] • Bioactivity of cafestol, a diterpene found in Coffea seeds, was studied. • Cafestol significantly affects mycelial growth of several phytopathogenic fungi. • Cafestol alters Bactrocera dorsalis larvae pupation and pupae development. • Fatty acid esters of diterpenes are stored in endosperm oil bodies. • Cafestol and kahweol are transferred to all seedling organs after germination. [ABSTRACT FROM AUTHOR]

Abstract: The genus Vanilla which belongs to the Orchidaceae family comprises more than 110 species of which two are commercially cultivated (Vanilla planifolia and Vanilla xtahitensis). The cured pods of these species are the source of natural vanilla flavor. In intensive cultivation systems the vines are threatened by viruses such as Cymbidium mosaic virus (CymMV). In order to investigate the effect of CymMV on the growth and metabolome of vanilla plants, four accessions grown in intensive cultivation systems under shadehouse, CR01 (V. planifolia), CR17 (V. xtahitensis), CR03 (V. planifolia × V. xtahitensis) and CR18 (Vanilla pompona), were challenged with an isolate of CymMV. CymMV infected plants of CR01, CR03 and CR17 had a reduced growth compared to healthy plants, while there was no significant difference in the growth of CR18 vines. Interestingly, CR18 had qualitatively more phenolic compounds in leaves and a virus titre that diminished over time. No differences in the metabolomic profiles of the shadehouse samples obtained by nuclear magnetic resonance (NMR) were observed between the virus infected vs. healthy plants. However, using in- vitro V. planifolia plants, the metabolomic profiles were affected by virus infection. Under these controlled conditions the levels of amino acids and sugars present in the leaves were increased in CymMV infected plants, compared to uninfected ones, whereas the levels of phenolic compounds and malic acid were decreased. The metabolism, growth and viral status of V. pompona accession CR18 contrasted from that of the other species suggesting the existence of partial resistance to CymMV in the vanilla germplasm. [Copyright &y& Elsevier]