Identification and Functional Analysis of CAD Gene Family in Pomegranate (Punica granatum).

[Objective] Cinnamyl alcohol dehydrogenase (CAD) is a key enzyme in lignin biosynthesis. The aim of this study was to identify CAD gene family members in pomegranate and its expression correlation with seed hardness. [Methods] Based on the reported CAD sequence of Arabidopsis, the CAD gene family of pomegranate was identified by homologous comparison, and then phylogenetic, molecular characterization, and expression profile analysis were performed. [Results] Pomegranate CAD gene family has 25 members, distributed on seven chromosomes of pomegranate. All pomegranate CAD proteins have similar physical and chemical properties. We divide the family into four groups based on evolutionary relationships. The member of group I, called bona fide CAD, was involved in lignin synthesis. Most of the members of group II were involved in stress resistance. The functions of groups III and IV need to be explored. We found four duplicated modes (whole genome duplication or segmental (WGD), tandem duplication (TD), dispersed duplication (DSD), proximal duplication (PD) in this family; TD (36%) had the largest number of them. We predicted that 20 cis-acting elements were involved in lignin synthesis, stress resistance, and response to various hormones. Gene expression profiles further demonstrated that the PgCAD gene family had multiple functions. [Conclusions] Pomegranate CAD gene family is involved in lignin synthesis of hard-seeded cultivar Hongyushizi and Baiyushizi, but its role in seed hardness of soft-seeded cultivar Tunisia needs to be further studied.

Molecular cloning and characterization of genes related to the ethylene signal transduction pathway in pomegranate (Punica granatum L.) under different temperature treatments.

Low temperature storage is a common method for storing pomegranates post-harvest; however, unsuitable low temperatures can cause fruit chilling injuries, the molecular mechanism of which is as yet unclear. Ethylene is a major factor affecting the post-harvest storage quality of pomegranates, and functions mainly through the ethylene signal transduction pathway. ERF1, ERF2 and ETR are key genes in the ethylene signal transduction pathway. Here, we used RACE and homologous cloning techniques to obtain PgERF1 (KU058889), PgERF2 (KU058890) and PgETR (KU058891) from Punica granatum cv. Yushizi. Sequence alignment and functional domain analysis revealed that both PgERF1 and PgERF2 contained a DNA-binding-site at the 120th to 177th amino acids of the N-terminus, which is a typical AP2/ERF center structure domain. Analysis of changes in expression of PgERF1, PgERF2 and PgETR following storage for different lengths of time (0, 14, 28, 42 and 56 days) at different temperatures (0°C, 5°C, 10°C and 15°C) revealed that the expression levels of PgERF1 and PgERF2 had a significant positive correlation. At the same time, the expression of both PgERF1 and PgERF2 increased continuously with time when seeds were stored at 0°C. However, there was no obvious linear relationship between time stored and the levels of expression of PgETR. Therefore, we inferred that at 0°C, the ethylene signal transduction pathway might play an important role in fruit chilling injuries during post-harvest storage.

Synthesis of nanometer-size Bi3TaO7 and its visible-light photocatalytic activity for the degradation of a 4BS dye.

Most of tantalate photocatalysts are mainly synthesized by solid-state (SS) reaction methods and only show photocatalytic activity under UV light irradiation. Ta(2)O(5) as a raw material shows an extremely high chemical stability, limiting its application to a few systems. A novel nanometer Bi(3)TaO(7) photocatalyst was synthesized by a facile and low-cost sol-gel method using Ta(2)O(5) and Bi(NO(3))(3)·5H(2)O as the Ta and Bi sources, respectively. The as-obtained samples were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-vis diffuse reflection spectroscopy (DRS) and Fourier transform infrared spectroscopy (FT-IR). The band gap energy of the as-obtained nanometer Bi(3)TaO(7) photocatalyst was determined to be about 2.75-2.86 eV. The Bi(3)TaO(7) nanopowders show a strong adsorbability and a high visible-light photocatalytic activity for the degradation of 4BS, which can be ascribed to the surface physicochemical properties and structure of the Bi(3)TaO(7) nanometer catalyst. The degradation of 4BS is attributed to the photocatalysis but not to the adsorption of 4BS on the as-prepared catalyst.

Preparation of nanosized Bi3NbO7 and its visible-light photocatalytic property.

A nanosized Bi(3)NbO(7) was synthesized by the sol-gel method. The as-prepared samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), UV-vis diffuse reflectance spectrum, X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmet-Teller (BET). The UV-vis diffuse reflectance spectrum of the sample obtained by the sol-gel method showed a markedly blue-shift as compared to that of the sample obtained by the solid-state reaction. The band gap of the Bi(3)NbO(7) nanoparticles was estimated to be about 2.43-2.59eV. XPS analysis confirmed that the mixed valence bismuth existed in the crystal structure of the photocatalyst and niobium in the compound Bi(3)NbO(7) was in the Nb(5+) valence state. The as-prepared nanopowders exhibited a high photocatalytic activity in the decomposition of acid red G in water and acetone in air under visible-light irradiation, which may be assigned to larger specific surface area and the oxygen vacancies and mixed valence bismuth in the structure of Bi(3)NbO(7).

Genomic characterization of putative allergen genes in peach/almond and their synteny with apple.

BACKGROUND: Fruits from several species of the Rosaceae family are reported to cause allergic reactions in certain populations. The allergens identified belong to mainly four protein families: pathogenesis related 10 proteins, thaumatin-like proteins, lipid transfer proteins and profilins. These families of putative allergen genes in apple (Mal d 1 to 4) have been mapped on linkage maps and subsequent genetic study on allelic diversity and hypoallergenic traits has been carried out recently. In peach (Prunus persica), these allergen gene families are denoted as Pru p 1 to 4 and for almond (Prunus dulcis)Pru du 1 to 4. Genetic analysis using current molecular tools may be helpful to establish the cause of allergenicity differences observed among different peach cultivars. This study was to characterize putative peach allergen genes for their genomic sequences and linkage map positions, and to compare them with previously characterized homologous genes in apple (Malus domestica). RESULTS: Eight Pru p/du 1 genes were identified, four of which were new. All the Pru p/du 1 genes were mapped in a single bin on the top of linkage group 1 (G1). Five Pru p/du 2 genes were mapped on four different linkage groups, two very similar Pru p/du 2.01 genes (A and B) were on G3, Pru p/du 2.02 on G7,Pru p/du 2.03 on G8 and Pru p/du 2.04 on G1. There were differences in the intron and exon structure in these Pru p/du 2 genes and in their amino acid composition. Three Pru p/du 3 genes (3.01-3.03) containing an intron and a mini exon of 10 nt were mapped in a cluster on G6. Two Pru p/du 4 genes (Pru p/du 4.01 and 4.02) were located on G1 and G7, respectively. The Pru p/du 1 cluster on G1 aligned to the Mal d 1 clusters on LG16; Pru p/du 2.01A and B on G3 to Mal d 2.01A and B on LG9; the Pru p/du 3 cluster on G6 to Mal d 3.01 on LG12; Pru p/du 4.01 on G1 to Mal d 4.03 on LG2; and Pru p/du 4.02 on G7 to Mal d 4.02 on LG2. CONCLUSION: A total of 18 putative peach/almond allergen genes have been mapped on five linkage groups. Their positions confirm the high macro-synteny between peach/almond and apple. The insight gained will help to identify key genes causing differences in allergenicity among different cultivars of peach and other Prunus species.