Botanical Studies

Natural hybridization in plants is a vital mechanism of speciation. Calanthe arisanensis and C. sieboldii occur in the same habitat in northern Taiwan, where there are a number of plants whose morphologically characters are similar in between of these two species. In this report, a new natural hybrid, Calanthe species – C. xhsinchuensis Y.I. Lee putatively derived from the natural hybridization of C. arisanensis and C. sieboldii was described and illustrated. Besides, somatic chromosome number was counted. The morphological and histological data of flowers, capsules, roots and leaves of C. xhsinchuensis show an intermediate condition between its putative parents. The chromosome number, 2n = 40, is also congruent with its putative parents. Color plates and line drawings are provided to aid in identification. Base on the morphological characteristics of reproductive and vegetative organs, and the distributions of putative parents, it is proposed that C. xhsinchuensis is a natural hybrid between C. arisanensis Hayata and C. sieboldii Decaisne ex Regel.

Cadmium uptake and distribution, as well as its effects on lipid composition was investigated in almond seedlings (Prunus dulcis) grown in culture solution supplied with two concentrations of Cd (50 and 150 μM). The accumulation of Cd increased with external metal concentrations, and was considerably higher in roots than in leaves. Fourteen days after Cd treatment, the membrane lipids were extracted and separated on silica-gel thin layer chromatography (TLC). Fatty acid methyl esters were analyzed by FID-GC on a capillary column. Our results showed that Cd stress decreased the quantities of all lipids classes (phospholipids, galactolipids and neutral lipids). Galactolipid, phospholipid and neutral lipid concentrations decreased more in roots than in leaves by Cd-treatment. In almost all lipid classes the proportion of palmitic acid (16:0), linoleic (18: 2) and that of linolenic (18: 3) acid decreased, suggesting that heavy metal treatment induced an alteration in the fatty acid synthesis processes. In conclusion, our results show that the changes found in total fatty acids, in the quantities of all lipids classes, and in the in the profiles of individual polar lipids suggest that membrane structure and function might be altered by Cd stress.

Abstract Background Identification of natural antibacterial agents from various sources that can act effectively against disease causing foodborne bacteria is one of the major concerns throughout the world. However, the natural antibacterial agents identified to date are primarily effective against Gram positive bacteria, but less effective against Gram negative bacteria. In the present study, Enteromorpha linza L. essential oil (EEO) was evaluated for antibacterial activity against Escherichia coli and Salmonella Typhimurium along with the mode of their antibacterial action. Results The chemical composition of EEO revealed high amounts of acids (54.6 %) and alkenes (21.1 %). EEO was effective against both E. coli and S. Typhimurium. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of EEO for both pathogens were 12.5 mg/ml and 25.0 mg/mL, respectively. EEO at the MIC acted on the loss in viability of E. coli ATCC 43890, which was used as the model system for evaluation of the antibacterial mode of action of EEO against Gram negative bacteria. Significant increase in relative electrical conductivity and K+ concentration were recorded with respect to time, indicating the disruption of tested E. coli cells owing to the controlling effect of EEO. Alternation of the morphology of the cell surface, increase in the release of 260 nm absorbing materials and loss of high salt tolerance were observed. Conclusions The results suggest that EEO induced a bactericidal effect via structural membrane damage caused by deposition of EEO in the cytosol or through enzymatic degradation of bacterial intracellular enzymes that resulted in cellular lysis. Accordingly, EEO can be used as a strong natural antibacterial agent against Gram negative foodborne pathogens such as E. coli and S. Typhimurium.

The floral development of Dieffenbachia seguine (N. J. Jacquin) Schott is analysed in relation to the molecular phylogeny of the Spathicarpae by Cusimano et al. (Am J Bot 98:654–668, 2011). The initiation of discoid floral primordia occurs acropetally on the surface of the spadix. Female flowers, atypical bisexual flowers, sterile male flowers, and male flowers share the same phyllotactic spirals on the spadix. Four or five stamen primordia are initiated simultaneously on the periphery of the male floral meristem. During early stages of stamen initiation, individual stamen primordia are connate at their base. In a synandrium, stamen fusion occurs very early during their developmental cycle with the stamens being already united laterally when longitudinal elongation occurs. The staminodes are also initiated on the periphery of the discoid floral primordium, and their number varies from four to six. The development of the fused staminodes will eventually form a longitudinal cavity in the center of the mature synandrode. The atypical flowers located in the intermediate zone range in morphology from aborted female flowers to rudimentary sterile male flowers with incomplete staminodes. The development of the female flower of Dieffenbachia Schott presents some similarities with atypical bisexual flowers of Cercestis Schott representing one of three types of aberrant flower forms in the family. From a developmental point of view and in the context of a phylogeny of the group, we believe that the presence of staminodes in the female zone constitutes a plesiomorphy in the tribe Spathicarpeae.

Taichung Native 1 (TN1) is the first semidwarf rice cultivar that initiated the Green Revolution. As TN1 is a direct descendant of the Dee-geo-woo-gen cultivar, the source of the sd1 semidwarf gene, the sd1 gene can be defined through TN1. Also, TN1 is susceptible to the blast disease and is described as being drought-tolerant. However, genes related to these characteristics of TN1 are unknown. Our aim was to identify and characterize TN1 genes related to these traits. Aligning the sd1 of TN1 to Nipponbare sd1, we found a 382-bp deletion including a frameshift mutation. Sanger sequencing validated this deleted region in sd1, and we proposed a model of the sd1 gene that corrects errors in the literature. We also predicted the blast disease resistant (R) genes of TN1. Orthologues of the R genes in Tetep, a well-known resistant cultivar that is commonly used as a donor for breeding new blast resistant cultivars, were then sought in TN1, and if they were present, we looked for mutations. The absence of Pi54, a well-known R gene, in TN1 partially explains why TN1 is more susceptible to blast than Tetep. We also scanned the TN1 genome using the PosiGene software and identified 11 genes deemed to have undergone positive selection. Some of them are associated with drought-resistance and stress response. We have redefined the deletion of the sd1 gene in TN1, a direct descendant of the Dee-geo-woo-gen cultivar, and have corrected some literature errors. Moreover, we have identified blast resistant genes and positively selected genes, including genes that characterize TN1’s blast susceptibility and abiotic stress response. These new findings increase the potential of using TN1 to breed new rice cultivars.

N-ethyl-maleimide sensitive factor adaptor protein receptor (SNAREs) domain-containing proteins were known as key players in vesicle-associated membrane fusion. Genetic screening has revealed the function of SNAREs in different aspects of plant biology, but the role of many SNAREs are still unknown. In this study, we have characterized the role of Arabidopsis Qc-SNARE protein AtBS14b in brassinosteroids (BRs) signaling pathway. AtBS14b overexpression (AtBS14b ox) plants exhibited short hypocotyl and petioles lengths as well as insensitivity to exogenously supplied BR, while AtBS14b mutants did not show any visible BR-dependent morphological differences. BR biosynthesis enzyme BR6OX2 expression was slightly lower in AtBS14b ox than in wild type plants. Further BR-mediated repression of BR6OX2, CPD and DWF4 was inhibited in AtBS14b ox plants. AtBS14b-mCherry fusion protein localized in vesicular compartments surrounding plasma membrane in N. benthamiana leaves. In addition, isolation of AtBS14b-interacting BR signaling protein, which localized in plasma membrane, showed that AtBS14b directly interacted with membrane steroid binding protein 1 (MSBP1), but did not interact with BAK1 or BRI1. These data suggested that Qc-SNARE protein AtBS14b is the first SNARE protein identified that interacts with MSBP1, and the overexpression of AtBS14b modulates BR response in Arabidopsis.

Under natural conditions, ginger (Zingiber officinale Rosc.) rarely blossom and has seed, which limits new variety breeding of ginger and industry development. In this study, the effects of different photoperiods and light quality on flowering induction in ginger were performed, followed by gene expression analysis of flower buds differentiation under induced treatment using RNA-seq technology. First, both red light and long light condition (18 h light/6 h dark) could effectively induce differentiation of flower buds in ginger. Second, a total of 3395 differentially expressed genes were identified from several different comparisons, among which nine genes, including CDF1, COP1, GHD7, RAV2-like, CO, FT, SOC1, AP1 and LFY, were identified to be associated with flowering in induced flower buds and natural leaf buds. Aside from four down-regulated genes (CDF1, COP1, GHD7 and RAV2-like), other five genes were all up-regulated expression. These differentially expressed genes were mainly classified into 2604 GO categories, which were further enriched into 120 KEGG metabolic pathways. Third, expression change of flowering-related genes in ginger indicated that the induction may negatively regulated expression of CDF1, COP1, GHD7 and RAV2-like, and subsequently positively regulated expression of CO, FT, SOC1, LFY and AP1, which finally led to ginger flowering. In addition, the RNA-seq results were verified by qRT-PCR analysis of 18 randomly selected genes, which further demonstrated the reliability of transcriptome analysis. This study revealed the ginger flowering mechanism induced by light treatment and provided abundant gene information, which contribute to the development of hybrid breeding of ginger.

Grammitid ferns are a tropical monophyletic clade nested in Polypodiaceae, containing more than 20 genera and more than 750 species. Many of them also grow in Taiwan. During the survey of recent two decades, an unknown grammitid fern was discovered and the taxonomic treatment is given herein. A new species, collected from Taiwan, is recognized and named, i.e., Xiphopterella devolii S. J. Moore, Parris, & W. L. Chiou. The holotype is deposited in TAIF, and isotypes are in HAST, K, L, US, and TNS. It is also distributed on SE & S China. The genus Xiphopterella is also a new record to Taiwan. A new species, Xiphopterella devolii S. J. Moore, Parris, & W. L. Chiou is documented herein. The Xiphopterella is a new recorded genus in Taiwan and is first found beyond Malesia regions.