Characterization of the lipoxygenase (LOX) gene family in the Chinese white pear (Pyrus bretschneideri) and comparison with other members of the Rosaceae

Abstract

BackgroundLipoxygenases (LOXs), a type of non-haem iron-containing dioxygenase, are ubiquitous enzymes in plants and participate in the formation of fruit aroma which is a very important aspect of fruit quality. Amongst the various aroma volatiles, saturated and unsaturated alcohols and aldehydes provide the characteristic aroma of the fruit. These compounds are formed from unsaturated fatty acids through oxidation, pyrolysis and reduction steps. This biosynthetic pathway involves at least four enzymes, including LOX, the enzyme responsible for lipid oxidation. Although some studies have been conducted on the LOX gene family in several species including Arabidopsis, soybean, cucumber and apple, there is no information from pear; and the evolutionary history of this gene family in the Rosaceae is still not resolved.ResultsIn this study we identified 107 LOX homologous genes from five Rosaceous species (Pyrus bretschneideri, Malus × domestica, Fragaria vesca, Prunus mume and Prunus persica); 23 of these sequences were from pear. By using structure analysis, phylogenic analysis and collinearity analysis, we identified variation in gene structure and revealed the phylogenetic evolutionary relationship of this gene family. Expression of certain pear LOX genes during fruit development was verified by analysis of transcriptome data.Conclusions23 LOX genes were identified in pear and these genes were found to have undergone a duplication 30–45 MYA; most of these 23 genes are functional. Specific gene duplication was found on chromosome4 in the pear genome. Useful information was provided for future research on the evolutionary history and transgenic research on LOX genes.Electronic supplementary materialThe online version of this article (doi: 10.1186/1471-2164-15-444) contains supplementary material, which is available to authorized users.

Assessment of genetic structure among different pear species (Pyrusspp.) using apple-derived SSR and evidence of duplications in the pear genome

“…Segmental gene duplication was also reported in the pear genome. Li et al [51] found a total of 70 collinear gene pairs in the pear genome, which might have resulted from wholegenome duplication in pear millions of years ago. Recently, Cao et al [52] observed high level of gene duplication in P. bretschneideri and reported that wholegenome and segmental duplication likely played key roles in expansion of the MYB gene family in pear.…”

Proteomic analysis of the potential mechanism of fading of aroma‐related esters in “Nanguo” pears after long‐term refrigeration

“…Lipoxygenase, hydroperoxide lyase (HPL), and alcohol dehydrogenase (ADH) are key enzymes in the metabolism of aroma‐related esters in fruits (Both, Brackmann, & Thewes, ; Maschietto, Marocco, & Malachova, ; Tiggemann, Ballen, & Bocalon, ). Lipoxygenase can identify the 1,4‐isoprene structure of the unsaturated fatty acids, linoleic acid and linolenic acid, and oxidize the oxyhydroxy fatty acids to provide the substrate for subsequent synthesis of esters (Li et al, ). Hydroperoxide lyase is another important enzyme in the LOX pathway, which catalyzes the formation of hexanal from 13‐hydroperoxides (Ono, Handa, Koeduka, & Toyonaga, ).…”

Identification of nuclear genes controlling chlorophyll synthesis in barley by RNA-seq

“…It is a family of proteins that contain PLAT (Polycistin-1, Lipoxygenase, Alpha-Toxin) or LH2 (Lipoxygenase homology) domain [24]. This domain binds Ca 2+ ions [25].…”