The complete chloroplast genome sequence of Aspidopterys concava (Wall.) A. Juss. (Malpighiaceae).

Aspidopterys concava is related to a group of important medicinal plants in Malpighiaceae in southeast Asia. Here, we report the first chloroplast genome fully sequenced and annotated for Aspidopterys concava. The genome size was 160,441 bp and contained a large single-copy (LSC) region of 71,434 bp, a small single-copy (SSC) region of 53,544 bp, and a pair of inverted repeats (IRs) regions of 8943 bp. Total GC content was 37.9%. It contained 125 genes in total, comprising 82 protein-coding genes, 37 transfer RNA genes, and six ribosomal RNA genes. Phylogenetic analysis showed that A. concava was the most closely related to A. obcordata from the same genus.

Maintenance of Postharvest Quality and Reactive Oxygen Species Homeostasis of Pitaya Fruit by Essential Oil p-Anisaldehyde Treatment.

The performance of p-Anisaldehyde (PAA) for preserving pitaya fruit quality and the underpinning regulatory mechanism were investigated in this study. Results showed that PAA treatment significantly reduced fruit decay, weight loss and loss of firmness, and maintained higher content of total soluble solids, betacyanins, betaxanthins, total phenolics and flavonoids in postharvest pitaya fruits. Compared with control, the increase in hydrogen peroxide (H2O2) content and superoxide anion (O2•-) production was inhibited in fruit treated with PAA. Meanwhile, PAA significantly improved the activity of antioxidant enzymes superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT). Moreover, PAA-treated pitaya fruit maintained higher ascorbic acid (AsA) and reduced-glutathione (GSH) content but lower dehydroascorbate (DHA) and oxidized glutathione (GSSG) content, thus sustaining higher ratio of AsA/DHA and GSH/GSSG. In addition, activities of ascorbate peroxidase (APX), glutathione reductase (GR), monodehydroascorbate reductase (MDHAR) and dehydrogenation ascorbic acid reductase (DHAR), as well as the expression of HpSOD, HpPOD, HpCAT, HpAPX, HpGR, HpDHAR and HpMDHAR, were enhanced after PAA treatment. The findings suggest that postharvest application of PAA may be a reliable method to control postharvest decay and preserve quality of harvested pitaya fruit by enhancing the antioxidant potential of the AsA-GSH cycle and activating an antioxidant defense system to alleviate reactive oxygen species (ROS) accumulation.

Comparative transcriptional survey between self-incompatibility and self-compatibility in Citrus reticulata Blanco.

Seedlessness is an excellent economical trait, and self-incompatibility (SI) is one of important factors resulting in seedless fruit in Citrus. However, SI molecular mechanism in Citrus is still unclear. In this study, RNA-Seq technology was used to identify differentially expressed genes related to SI reaction of 'Wuzishatangju' (Citrus reticulata Blanco). A total of 35.67GB raw RNA-Seq data was generated and was de novo assembled into 50,364 unigenes with an average length of 897bp and N50 value of 1549. Twenty-three candidate unigenes related to SI were analyzed using qPCR at different tissues and stages after self- and cross-pollination. Seven pollen S genes (Unigene0050323, Unigene0001060, Unigene0004230, Unigene0004222, Unigene0012037, Unigene0048889 and Unigene0004272), three pistil S genes (Unigene0019191, Unigene0040115, Unigene0036542) and three genes (Unigene0038751, Unigene0031435 and Unigene0029897) associated with the pathway of ubiquitin-mediated proteolysis were identified. Unigene0031435, Unigene0038751 and Unigene0029897 are probably involved in SI reaction of 'Wuzishatangju' based on expression analyses. The present study provides a new insight into the molecular mechanism of SI in Citrus at the transcriptional level.

Identifying differentially expressed genes in pollen from self-incompatible "Wuzishatangju" and self-compatible "Shatangju" mandarins.

Self-incompatibility (SI) is one of the important factors that can result in seedless fruit in Citrus. However, the molecular mechanism of SI in Citrus is not yet clear. In this study, two suppression subtractive hybridization (SSH) libraries (forward, F and reverse, R) were constructed to isolate differentially expressed genes in pollen from "Wuzishatangju" (SI) and "Shatangju" (self-compatibility, SC) mandarins. Four hundred and sixty-eight differentially expressed cDNA clones from 2077 positive clones were sequenced and identified. Differentially expressed ESTs are possibly involved in the SI reaction of "Wuzishatangju" by regulating pollen development, kinase activity, ubiquitin pathway, pollen-pistil interaction, and calcium ion binding. Twenty five SI candidate genes were obtained, six of which displayed specific expression patterns in various organs and stages after self- and cross-pollination. The expression level of the F-box gene (H304) and S1 (F78) in the pollen of "Wuzishatangju" was 5-fold higher than that in "Shatangju" pollen. The F-box gene, S1, UBE2, UBE3, RNaseHII, and PCP were obviously up-regulated in pistils at 3 d after self-pollination of "Wuzishatangju", approximately 3-, 2-, 10-, 5-, 5-, and 2-fold higher, respectively than that at the same stage after cross-pollination of "Wuzishatangju" × "Shatangju" pistils. The potential involvement of these genes in the pollen SI reaction of "Wuzishatangju" is discussed.

Cloning and expression analysis of S-RNase homologous gene in Citrus reticulata Blanco cv. Wuzishatangju.

S-RNase-based self-incompatibility is the most widespread form of genetically controlled mate selection in plants and that S-RNase controls pollination specificity in the pistils. 'Wuzishatangju' (Citrus reticulata Blanco), a nature bud mutant from a self-compatible (SC) cultivar 'Shatangju', displays gametophytic self-incompatibility (GSI). In this study, full-length sequences of cDNA and DNA of the S-RNase homologous gene were obtained from 'Wuzishatangju' and 'Shatangju'. There was no difference in ORF sequences of the S-RNase cDNA between 'Wuzishatangju' and 'Shatangju'. However, 13, 9 and 6 consecutive bases were missing in 'Wuzishatangju' cDNA 5' UTR, 3' UTR and genomic DNA, respectively. Tissue-specific expression of the S-RNase gene was detected using semi-quantitative RT-PCR and quantitative real-time PCR. The expression level of the S-RNase gene in styles of 'Wuzishatangju' was approximately 10- and 5-fold higher than that in leaves and pollen, respectively. When 'Wuzishatangju' was self-pollinated, the expression of S-RNase in pistils peaked at 3 days, which was approximately 10-fold higher than that at 4h and 7 days, while in cross-pollination of 'Wuzishatangju' x 'Shatangju' the expression was very weak at 3 days. Results from a Southern blot showed that two copies of the S-RNase gene existed in genomic DNA of both 'Wuzishatangju' and 'Shatangju'.