Essential Oil Variation from Twenty Two Genotypes of Citrus in Brazil—Chemometric Approach and Repellency Against Diaphorina citri Kuwayama

Abstract

Abstract:The chemical composition of volatile oils from 22 genotypes of Citrus and related genera was poorly differentiated, but chemometric techniques have clarified the relationships between the 22 genotypes, and allowed us to understand their resistance to D. citri. The most convincing similarities include the synthesis of (Z)-β-ocimene and (E)-caryophyllene for all 11 genotypes of group A. Genotypes of group B are not uniformly characterized by essential oil compounds. When stimulated with odor sources of 22 genotypes in a Y-tube olfactometer D. citri preferentially entered the arm containing the volatile oils of Murraya paniculata, confirming orange jasmine as its best host. C. reticulataˆC. sinensis was the least preferred genotype, and is characterized by the presence of phytol, (Z)-β-ocimene, and β-elemene, which were not found in the most preferred genotype. We speculate that these three compounds may act as a repellent, making these oils less attractive to D. citri.

Genomic Analysis of Terpene Synthase Family and Functional Characterization of Seven Sesquiterpene Synthases from Citrus sinensis

“…Linalool/nerolidol synthase gene expression was induced in mandarin leaves by wounding and Xhantomonas citri infection (Shimada et al, 2014 ). Some mono and sesquiterpene compounds have been proposed to be important in the relation of citrus hosts with D. citri , vector of Candidatus Liberibacters (Patt and Sétamou, 2010 ; Coutinho-Abreu et al, 2014 ; Lin et al, 2016 ; dos Santos Andrade et al, 2016 ; Alquézar et al, 2017 ). However, in spite of their importance, just five citrus SesquiTPSs have been characterized up to date (Maruyama et al, 2001 ; Sharon-Asa et al, 2003 ; Shimada et al, 2012 , 2014 ; Uji et al, 2015 ).…”

“…Most of the amino acid changes between Satsuma mandarin linalool/nerolidol synthase and Cs4g12110.1, which clustered together, were also found at the non-catalytic N-terminus, with just one substitution for an amino acid with similar accessible surface area in the C-terminal position (M351I counted on BAP75561 sequence). As nerolidol is accumulated in different Valencia sweet orange tissues (Njoroge et al, 2005 ; dos Santos Andrade et al, 2016 ), it can be assumed that Cs4g12110.1 encodes a functional nerolidol/linalool synthase despite the change in hydrophobicity of the single altered amino acid found in the C-terminus. Although germacrene-A, δ-elemene and β-farnesene synthases had been characterized from other Citrus types (Maruyama et al, 2001 ; Shimada et al, 2012 ; Uji et al, 2015 ), phylogenetic and homology analysis did not allow a reliable prediction of any orange putative SesquiTPS with these activities.…”

Epifluorescence and stereomicroscopy of trichomes associated with resistant and susceptible host plant genotypes of the asian citrus psyllid (Hemiptera: Liviidae), Vector of citrus greening disease bacterium

“…[ 11 12 ] although the level of resistance to the psyllid has been variable possibly due to environmental conditions, plant age, and other factors. Both antixenosis and antibiosis types of plant resistance to D. citri have been noted in trifoliate orange,[ 11 13 ] but the specific traits conferring resistance remain unclear. With respect to reduced oviposition rates on trifoliate orange, it has been thought that kairomones or secondary plant metabolites may be involved,[ 14 ] but factors related to plant morphology have not been investigated so far.…”

Effects of β-caryophyllene and Murraya paniculata essential oil in the murine hepatoma cells and in the bacteria and fungi 24-h time–kill curve studies

“… 2012 ), and repellency against Diaphorina citri Kuwayama (Andrade et al. 2016 ). In addition, no data were found for the main isolated compounds as well.…”