Adventitious root primordia formation and development in the stem of Ananas comosus var. bracteatus slip.

There are about 4-6 slips on a fruit, and they are good materials for effective regeneration of Ananas comosus var. bracteatus. Adventitious root (AR) induction is essential for the propagation of Ananas comosus var. bracteatus slips. Growth regulator treatment, and culture medium are imperative factors that affect slip growth and rooting. In order to screen the optimal methods for slips rooting and reveal the anatomic procedure of slip rooting, this study induced slip rooting by different treatment of growth regulator, culture medium, observed the slip stem structure, AR origination and formation procedure through paraffin sections. The results showed that, slip cuttings treated with 100 mg/L of Aminobenzotriazole (ABT) for 6 hrs, cultured in river sand: coconut chaff: garden soil 2:2:1 medium is the optimal method for rooting. The proper supplementary of ABT can enhance the soluble sugar content, soluble protein content, polyphenol oxidase (PPO) activity and peroxidase (POD) enzyme activity, which resulted in the improvement of rooting. The slip stem structure is quite different from other monocots, which consists of epidermis, cortex, and stele with vascular tissues distributed in the cortex and stele. The AR primordia originates from the parenchyma cells located on the borderline between the cortex and stele. The vascular tissues in the AR develop and are connected with vascular tissue of the stem before the AR grew out the stem. The number of primary xylem poles in AR is about 30.

Screening and characterization of long noncoding RNAs involved in the albinism of Ananas comosus var. bracteatus leaves.

Long noncoding RNAs (lncRNAs) have been reported to play key regulatory roles in plant growth, development, and biotic and abiotic stress physiology. Revealing the mechanism of lncRNA regulation in the albino portions of leaves is important for understanding the development of chimeric leaves in Ananas comosus var. bracteatus. In this study, a total of 3,543 candidate lncRNAs were identified, among which 1,451 were differentially expressed between completely green (CGr) and completely white (CWh) leaves. LncRNAs tend to have shorter transcripts, lower expression levels, and greater expression specificity than protein-coding genes. Predicted lncRNA targets were functionally annotated by the Gene Ontology (GO), Clusters of Orthologous Groups (COG) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases. A lncRNA-mRNA interaction network was constructed, and 36 target mRNAs related to chlorophyll metabolism were predicted to interact with 86 lncRNAs. Among these, 25 significantly differentially expressed lncRNAs putatively interacted with 16 target mRNAs. Based on an expression pattern analysis of the lncRNAs and their target mRNAs, the lncRNAs targeting magnesium chelatase subunit H (ChlH), protochlorophyllide oxidoreductase (POR), and heme o synthase (COX10) were suggested as key regulators of chlorophyll metabolism. This study provides the first lncRNA database for A. comosus var. bracteatus and contributes greatly to understanding the mechanism of epigenetic regulation of leaf albinism.

SMRT sequencing analysis reveals the full-length transcripts and alternative splicing patterns in Ananas comosus var. bracteatus.

BACKGROUND: Ananas comosus var. bracteatus is an herbaceous perennial monocot cultivated as an ornamental plant for its chimeric leaves. Because of its genomic complexity, and because no genomic information is available in the public GenBank database, the complete structure of the mRNA transcript is unclear and there are limited molecular mechanism studies for Ananas comosus var. bracteatus. METHODS: Three size fractionated full-length cDNA libraries (1-2 kb, 2-3 kb, and 3-6 kb) were constructed and subsequently sequenced in five single-molecule real-time (SMRT) cells (2 cells, 2 cells, and 1 cell, respectively). RESULTS: In total, 19,838 transcripts were identified for alternative splicing (AS) analysis. Among them, 19,185 (96.7%) transcripts were functionally annotated. A total of 9,921 genes were identified by mapping the non-redundant isoforms to the reference genome. A total of 10,649 AS events were identified, the majority of which were intron retention events. The alternatively spliced genes had functions in the basic metabolism processes of the plant such as carbon metabolism, amino acid biosynthesis, and glycolysis. Fourteen genes related to chlorophyll biosynthesis were identified as having AS events. The distribution of the splicing sites and the percentage of conventional and non-canonical AS sites of the genes categorized in pathways related to the albino leaf phenotype (ko00860, ko00195, ko00196, and ko00710) varied greatly. The present results showed that there were 8,316 genes carrying at least one poly (A) site, which generated 21,873 poly (A) sites. These findings indicated that the quality of the gene structure and functional information of the obtained genome was greatly improved, which may facilitate further genetic study of Ananas comosus var. bracteatus.

[The effects of Kangai injection on enzyme activities of macrophages in rats].

OBJECTIVE: To study the effects of Kangai injection on the enzyme activities of macrophages and morphology of spleen and thymus from rats. METHODS: Twenty four male SD rats were randomly divided into two groups (n = 12), normal control group and experimental group. The rats in experimental group were injected with Kangai injection at the dosage of 5 ml/kg x d for 30 days peritoneally and those in control group were injected with nomal saline at the same volume. The content of supermicro protein was assayed by BCA method, the activities of lactate dehydrogenase (LDH), glutathione peroxidase(GSH-Px), and inducible nitric oxide synthase (iNOS) from alveolar macrophages(AM) and peritoneal macrophages (PM) were detected biochemically. The activities of acid phosphatase (ACP), superoxide dismutase(SOD) and succinate dehydrogenase (SDH) from AM and PM were detected by ELISA. The morphology of spleen and thymus were observed by light microscopy. RESULTS: The activities of LDH, GSH-Px and iNOS within AM and PM from experimental group were increased significantly compared with those of control group (P < 0.05). The activities of ACP, SOD and SDH in AM and PM from experimental group were also higher than those from control group (P < 0.05). Microscopically, there was thickening of peripheral arterial lymphatic sheath, enlargement of splenic lymphoid nodules with expended germinal center in the spleen of experimental group. There was no significant difference in the mophology of thymus between the two groups. CONCLUSION: Kangai injection may improve immune function by activating macrophages.