Complete chloroplast genome of Boesenbergia rotunda and a comparative analysis with members of the family Zingiberaceae

Boesenbergia rotunda (L.) Mansf. is a medically important ginger species of the family Zingiberaceae but its genomic information on molecular phylogeny and identification is scarce. In this work, the chloroplast genome of B. rotunda was sequenced, characterized and compared to the other Zingiberaceae species to provide chloroplast genetic resources and to determine its phylogenetic position in the family. The chloroplast genome of B. rotunda was 163,817 bp in length and consisted of a large single-copy (LSC) region of 88,302 bp, a small single-copy (SSC) region of 16,023 bp and a pair of inverted repeats (IRA and IRB) of 29,746 bp each. The chloroplast genome contained 113 unique genes, including 79 protein-coding genes, 30 transfer RNA (tRNA) genes and four ribosomal RNA (rRNA) genes. Several genes had atypical start codons, while most amino acids exhibited biased usage of synonymous codons. Comparative analyses with various chloroplast genomes of Zingiberaceae taxa revealed several highly variable regions (psbK-psbI, trnT-GGU-psbD, rbcL-accD, ndhF-rpl32, and ycf1) in the LSC and SSC regions in the chloroplast genome of B. rotunda that could be utilized as molecular markers for DNA barcoding and species delimitation. Phylogenetic analyses based on shared protein-coding genes revealed that B. rotunda formed a distinct lineage with B. kingii Mood & L.M.Prince, in a subclade that also contained the genera Kaempferia and Zingiber. These findings constitute the first chloroplast genome information of B. rotunda that could be a reference for phylogenetic analysis and identification of genus Boesenbergia within the Zingiberaceae family.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s40415-022-00845-w.

The Immunobiology of Nipah Virus

Nipah virus (NiV) is a highly lethal zoonotic paramyxovirus that emerged in Malaysia in 1998. It is a human pathogen capable of causing severe respiratory infection and encephalitis. The natural reservoir of NiV, Pteropus fruit bats, remains a continuous virus source for future outbreaks, although infection in the bats is largely asymptomatic. NiV provokes serious disease in various mammalian species. In the recent human NiV outbreaks in Bangladesh and India, both bats-to-human and human-to-human transmissions have been observed. NiV has been demonstrated to interfere with the innate immune response via interferon type I signaling, promoting viral dissemination and preventing antiviral response. Studies of humoral immunity in infected NiV patients and animal models have shown that NiV-specific antibodies were produced upon infection and were protective. Studies on cellular immunity response to NiV infection in human and animal models also found that the adaptive immune response, specifically CD4+ and CD8+ T cells, was stimulated upon NiV infection. The experimental vaccines and therapeutic strategies developed have provided insights into the immunological requirements for the development of successful medical countermeasures against NiV. This review summarizes the current understanding of NiV pathogenesis and innate and adaptive immune responses induced upon infection.

Enhancing flavonoid production by promiscuous activity of prenyltransferase, BrPT2 from Boesenbergia rotunda

Flavonoids and prenylated flavonoids are active components in medicinal plant extracts which exhibit beneficial effects on human health. Prenylated flavonoids consist of a flavonoid core with a prenyl group attached to it. This prenylation process is catalyzed by prenyltranferases (PTs). At present, only a few flavonoid-related PT genes have been identified. In this study, we aimed to investigate the roles of PT in flavonoid production. We isolated a putative PT gene (designated as BrPT2) from a medicinal ginger, Boesenbergia rotunda. The deduced protein sequence shared highest gene sequence homology (81%) with the predicted homogentisate phytyltransferase 2 chloroplastic isoform X1 from Musa acuminata subsp. Malaccensis. We then cloned the BrPT2 into pRI vector and expressed in B. rotunda cell suspension cultures via Agrobacterium-mediated transformation. The BrPT2-expressing cells were fed with substrate, pinostrobin chalcone, and their products were analyzed by liquid chromatography mass spectrometry. We found that the amount of flavonoids, namely alpinetin, pinostrobin, naringenin and pinocembrin, in BrPT2-expressing cells was higher than those obtained from the wild type cells. However, we were unable to detect any targeted prenylated flavonoids. Further in-vitro assay revealed that the reaction containing the BrPT2 protein produced the highest accumulation of pinostrobin from the substrate pinostrobin chalcone compared to the reaction without BrPT2 protein, suggesting that BrPT2 was able to accelerate the enzymatic reaction. The finding of this study implied that the isolated BrPT2 may not be involved in the prenylation of pinostrobin chalcone but resulted in high yield and production of other flavonoids, which is likely related to enzyme promiscuous activities.