The quadriflagellate genus Chlainomonas frequently dominates red snow globally. It is unusual in several respects, with two separated pairs of flagella, apparent cell division via extrusion of cytoplasmic threads, and being nested phylogenetically within the biflagellate genus Chloromonas. Here, we showed that the austral species Chloromonas (Cr.) rubroleosa, originally described from Antarctic red snow, is a close biflagellate relative of Chlainomonas, challenging the monophyly of Chlainomonas as currently conceived. Sequences of the 18S rRNA gene robustly linked Cr. rubroleosa with near-identical environmental sequences from Antarctic red snow and Chlainomonas from North America, Japan, and Europe. Furthermore, the 18S rRNA and rbcL gene sequences of Cr. rubroleosa were almost identical to New Zealand and North American collections of Chlainomonas. Cr. rubroleosa and New Zealand Chlainomonas are separated by only a single-base substitution across the ITS1-5.8S-ITS2 rRNA loci (and according to ITS2, the North American collection is the next closest relative). This again raises the possibility that Chlainomonas is a life-cycle stage of vegetatively biflagellate organisms, although this remains confounded by the scarcity of biflagellates in field populations, the apparent cell division by quadriflagellates, and the absence of Chlainomonas-type cells in cultures of Cr. rubroleosa. The latter species is broadly similar to Chlainomonas, being poor at swimming, with similar pigment, chloroplast arrangement and ultrastructure, and is relatively large. Increased size is a feature of the wider clade of "Group D" snow algae. A synthesis of field and laboratory investigations may be needed to unravel the life cycle and correct the systematics of this group.
Climate warming may be exacerbated if rising temperatures stimulate losses of soil carbon to the atmosphere. The direction and magnitude of this carbon-climate feedback are uncertain, largely due to lack of knowledge of the thermal adaptation of the physiology and composition of soil microbial communities. Here, we applied the macromolecular rate theory (MMRT) to describe the temperature response of the microbial decomposition of soil organic matter (SOM) in a natural long-term warming
Yam is an important food staple for millions of people globally, particularly those in the developing countries of West Africa and the Pacific Islands. To sustain the growing population, yam production must be increased amidst the many biotic and abiotic stresses. Plant viruses are among the most detrimental of plant pathogens and have caused great losses of crop yield and quality, including those of yam. Knowledge and understanding of virus biology and ecology are important for the development of diagnostic tools and disease management strategies to combat the spread of yam-infecting viruses. This review aims to highlight current knowledge on key yam-infecting viruses by examining their characteristics, genetic diversity, disease symptoms, diagnostics, and elimination to provide a synopsis for consideration in developing diagnostic strategy and disease management for yam.
Despite recent advances in high-throughput DNA sequencing technologies,
a lack of locally relevant DNA reference databases may limit the
potential for DNA-based monitoring of biodiversity for conservation and
biosecurity applications. Museums and national collections represent a
compelling source of authoritatively identified genetic material for DNA
database development yet obtaining DNA barcodes from long-stored
specimens may be difficult due to sample degradation. We demonstrate a
sensitive and efficient laboratory and bioinformatic process for
generating DNA barcodes from hundreds of invertebrate specimens
simultaneously via the Illumina MiSeq system. Using this process, we
recovered full-length (334) or partial (105) COI barcodes from 439 of
450 (98 %) national collection-held invertebrate specimens. This
included full-length barcodes from 146 specimens which produced
low-yield DNA and no visible PCR bands, and which produced as little as
a single sequence per specimen, demonstrating high sensitivity of the
process. In many cases, the identity of the most abundant sequences per
specimen were not the correct barcodes, necessitating the development of
a taxonomy-informed process for identifying correct sequences among the
sequencing output. The recovery of only partial barcodes for some taxa
indicates a need to refine certain PCR primers. Nonetheless, our
approach represents a highly sensitive, accurate, and efficient method
for targeted reference database generation, providing a foundation for
DNA-based assessments and monitoring of biodiversity.
Despite recent advances in high‐throughput DNA sequencing technologies, a lack of locally relevant DNA reference databases limits the potential for DNA‐based monitoring of biodiversity for conservation and biosecurity applications. Museums and national collections represent a compelling source of authoritatively identified genetic material for DNA database development, yet obtaining DNA barcodes from long‐stored specimens may be difficult due to sample degradation. Here we demonstrate a sensitive and efficient laboratory and bioinformatic process for generating DNA barcodes from hundreds of invertebrate specimens simultaneously via the Illumina MiSeq system. Using this process, we recovered full‐length (334) or partial (105) COI barcodes from 439 of 450 (98%) national collection‐held invertebrate specimens. This included full‐length barcodes from 146 specimens which produced low‐yield DNA and no visible PCR bands, and which produced as little as a single sequence per specimen, demonstrating high sensitivity of the process. In many cases, the identity of the most abundant sequences per specimen were not the correct barcodes, necessitating the development of a taxonomy‐informed process for identifying correct sequences among the sequencing output. The recovery of only partial barcodes for some taxa indicates a need to refine certain PCR primers. Nonetheless, our approach represents a highly sensitive, accurate and efficient method for targeted reference database generation, providing a foundation for DNA‐based assessments and monitoring of biodiversity.
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