Search

Bluetongue virus (BTV) and epizootic hemorrhagic disease virus (EHDV) are vector-borne orbiviruses that pose an emerging threat to livestock, including cattle and sheep. This review summarizes the global distribution, genetic diversity, and key factors driving their spread along with the existing knowledge gaps and recommendations to mitigate their impact. Both viruses cause hemorrhagic disease in susceptible ruminants and are commonly reported in tropical and subtropical regions including North America, Asia, Africa, Oceania, and some parts of Europe. The geographical distribution of these viruses, encompassing 27 BTV and 7 EHDV serotypes, has shifted, particularly with the recent invasion of BTV-3, 4, and 8 and EHDV-8 serotypes in Europe. Several factors contribute to the recent spread of these viruses such as the distribution of virulent strains by the movement of temperature-dependent Culicoides vectors into new areas due to rapid climate change, the reassortment of viral strains during mixed infections, and unrestricted global trade. These diseases cause significant economic impacts including morbidity, mortality, reduced production, high management costs, and the disruption of international trade. Effective prevention and control strategies are paramount and rely on vaccination, vector control using insecticides, and the destruction of breeding sites, husbandry practices including the isolation and quarantine of infected hosts, restriction of animal movement, prompt diagnosis and identification of circulating strains, and effective surveillance and monitoring plans such as the pre-export and post-import screening of semen used for artificial insemination. However, challenges remain with intercontinental virus spread, live vaccines, and the failure of inactivated vaccines to produce protective immunity against dissimilar strains. Significant knowledge gaps highlight the need for a better scientific understanding and a strategic plan to ensure healthy livestock and global food security. [ABSTRACT FROM AUTHOR]

Heavy and costly use of phosphorus (P) fertiliser is often needed to achieve high crop yields, but only a small amount of applied P fertiliser is available to most crop plants. Hakea prostrata (Proteaceae) is endemic to the P‐impoverished landscape of southwest Australia and has several P‐saving traits. We identified 16 members of the Phosphate Transporter 1 (PHT1) gene family (HpPHT1;1‐HpPHT1;12d) in a long‐read genome assembly of H. prostrata. Based on phylogenetics, sequence structure and expression patterns, we classified HpPHT1;1 as potentially involved in Pi uptake from soil and HpPHT1;8 and HpPHT1;9 as potentially involved in Pi uptake and root‐to‐shoot translocation. Three genes, HpPHT1;4, HpPHT1;6 and HpPHT1;8, lacked regulatory PHR1‐binding sites (P1BS) in the promoter regions. Available expression data for HpPHT1;6 and HpPHT1;8 indicated they are not responsive to changes in P supply, potentially contributing to the high P sensitivity of H. prostrata. We also discovered a Proteaceae‐specific clade of closely‐spaced PHT1 genes that lacked conserved genetic architecture among genera, indicating an evolutionary hot spot within the genome. Overall, the genome assembly of H. prostrata provides a much‐needed foundation for understanding the genetic mechanisms of novel adaptations to low P soils in southwest Australian plants. [ABSTRACT FROM AUTHOR]

Pulse production is decreased when grown on waterlogged soil in rice‐based cropping. This study evaluated four pulse crops—grass pea, field pea, cowpea and lentil—to find out their responses to waterlogging (WL) stress at emergence and vegetative stages. The treatment levels at emergence were drained control, 4‐, 7‐ and 10‐day WL, while in the vegetative stage they were drained control, 6‐, 10‐ and 14‐day WL. In the emergence stage, %emergence was significantly reduced as WL duration increased. After 10‐day WL, emergence was reduced to 65% for grass pea, 30% for field pea, 5% for lentil and 7% for cowpea. At the vegetative stage, in both the WL and recovery phases, the WL treatment reduced plant height, tap root length, shoot and root dry mass compared to those in drained control with a significant difference in crops. In recovery as compared to the WL phase at 14‐day WL, the chlorophyll content was increased 15% in cowpea and 14% in grass pea but decreased in field pea (26%) and lentil (35%). Similarly, in the recovery phase at 14‐day WL, shoot relative growth rates (RGRs) of cowpea, grass pea, field pea and lentil were 20, 66, 10 and 5 mg plant−1 d−1; which were 66%, 70%, 8% and 14% of drained control, respectively. The RGR of root at 14‐day WL was also higher in cowpea and grass pea with the rate of 13.8 and 16 mg−1 plant−1 d−1, respectively; in sharp contrast to a reduction of −4.3 mg−1 plant−1 d−1 in field pea and −3.9 mg−1 plant−1 d−1 for lentil than drained control. Furthermore, the higher number of adventitious roots was found in cowpea (14) and grass (9) pea than in field pea (6) and lentil (4). Comparison between growth stages, grass pea was tolerant to WL in both stages. Cowpea was WL sensitive at emergence, but tolerant to vegetative stage. Field pea was moderately tolerant to emergence but was sensitive at vegetative stage. Lentil was sensitive at WL at both stages. These novel insights will allow the fitting of winter pulses to various cropping systems according to the perceived risk of WL at various growth stages. [ABSTRACT FROM AUTHOR]

Austropuccinia psidii is the causal agent of myrtle rust in over 480 species within the family Myrtaceae. Lineages of A. psidii are structured by their hosts in the native range, and some have success in infecting newly encountered hosts. For example, the pandemic biotype has spread beyond South America, and proliferation of other lineages is an additional risk to biodiversity and industries. Efforts to manage A. psidii incursions, including lineage differentiation, relies on variable microsatellite markers. Testing these markers is time-consuming, complex, and requires reference material that is not always readily available. We designed a novel diagnostic approach targeting eight selectively chosen loci including the fungal mating-type HD (homeodomain) transcription factor locus. The HD locus ( bW1/2-HD1 and bE1/2-HD2 ) is highly polymorphic, facilitating clear biological predictions about its inheritance from founding populations. To be considered as potentially derived from the same lineage, all four HD alleles must be identical. If all four HD alleles are identical six additional markers can further differentiate lineage identity. Our lineage diagnostics relies on PCR amplification of eight loci in different genotypes of A. psidii followed by amplicon sequencing using Oxford Nanopore Technologies (ONT) and comparative analysis. The lineage-specific assay was validated on four isolates with existing genomes, uncharacterized isolates, and directly from infected leaf material. We reconstructed alleles from amplicons and confirmed their sequence identity relative to their reference. Genealogies of alleles confirmed the variations at the loci among lineages/isolates. Our study establishes a robust diagnostic tool for differentiating known lineages of A. psidii based on biological predictions and available nucleotide sequences. This tool is suited to detecting the origin of new pathogen incursions.