Welcome to Massey Research Online
Massey Research Online is an open access digital archive of the research and scholarship of Massey University and is jointly managed by the University Library and Information Technology Services.
Massey Research Online contains research theses and research outputs including published work by Massey University students and academic staff as well as peer-reviewed material not published elsewhere. In the case of previously published research outputs all requirements of copyright owners are observed.
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Characterization of two conserved cell death elicitor families from the Dothideomycete fungal pathogens Dothistroma septosporum and Fulvia fulva (syn. Cladosporium fulvum)
(Frontiers Media S.A., 2022-09-08) Tarallo M; McDougal RL; Chen Z; Wang Y; Bradshaw RE; Mesarich CH; Wang Y
Dothistroma septosporum (Ds) and Fulvia fulva (Ff; previously called Cladosporium fulvum) are two closely related Dothideomycete fungal species that cause Dothistroma needle blight in pine and leaf mold in tomato, respectively. During host colonization, these pathogens secrete virulence factors termed effectors to promote infection. In the presence of corresponding host immune receptors, however, these effectors activate plant defenses, including a localized cell death response that halts pathogen growth. We identified two apoplastic effector protein families, Ecp20 and Ecp32, which are conserved between the two pathogens. The Ecp20 family has four paralogues in both species, while the Ecp32 family has four paralogues in D. septosporum and five in F. fulva. Both families have members that are highly expressed during host infection. Members of the Ecp20 family have predicted structural similarity to proteins with a β-barrel fold, including the Alt a 1 allergen from Alternaria alternata, while members of the Ecp32 family have predicted structural similarity to proteins with a β-trefoil fold, such as trypsin inhibitors and lectins. Using Agrobacterium tumefaciens-mediated transient transformation assays, each family member was assessed for its ability to trigger cell death in leaves of the non-host species Nicotiana benthamiana and N. tabacum. Using this approach, FfEcp20-2, DsEcp20-3, and FfEcp20-3 from the Ecp20 family, and all members from the Ecp32 family, except for the Ds/FfEcp32-4 pair, triggered cell death in both species. This cell death was dependent on secretion of the effectors to the apoplast. In line with recognition by an extracellular immune receptor, cell death triggered by Ds/FfEcp20-3 and FfEcp32-3 was compromised in N. benthamiana silenced for BAK1 or SOBIR1, which encode extracellular co-receptors involved in transducing defense response signals following apoplastic effector recognition. We then investigated whether DsEcp20-3 and DsEcp20-4 triggered cell death in the host species Pinus radiata by directly infiltrating purified protein into pine needles. Strikingly, as in the non-host species, DsEcp20-3 triggered cell death, while DsEcp20-4 did not. Collectively, our study describes two new candidate effector families with cell death-eliciting activity from D. septosporum and F. fulva and provides evidence that members of these families are recognized by plant immune receptors.
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The Potential Challenges and Limitations of Implementing Modern Office Design Features in Residential Spaces: A SPAR-4-SLR Approach
(2024-09-03) Rotimi JOB; Moshood TD; Rotimi FE
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Becoming and being language teacher educators: a collaborative reflexive account
(Taylor and Francis Group, 2024-11-14) Nguyen M; Qi GY
In this study we employed reflexivity as a typology and a means to foster our own becoming and being as language teacher educators (LTEs). Specifically, drawing on reflexivity as mutual collaboration, we engaged in duoethnography where we were researcher-participants in each other’s narratives, with the capacity to be reflexive beings. We collaboratively inquired into our own and one another’s professional trajectories, demonstrating how our journeys of becoming and being LTEs were characterised by our social and linguistic identities, our work and interaction with language teachers, and the research and teaching praxis. Findings and discussion advocate a dialogue in the field, acknowledging the dispositions, challenges, and possibilities that reflexivity can offer for LTEs’ trajectories.
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BatchHL+: batch dynamic labelling for distance queries on large-scale networks
(Springer-Verlag GmbH Germany, part of Springer Nature, 2024-01) Farhan M; Koehler H; Wang Q
Many real-world applications operate on dynamic graphs to perform important tasks. In this article, we study batch-dynamic algorithms that are capable of updating distance labelling efficiently in order to reflect the effects of rapid changes on such graphs. To explore the full pruning potentials, we first characterize the minimal set of vertices being affected by batch updates. Then, we reveal patterns of interactions among different updates (edge insertions and edge deletions) and leverage them to design pruning rules for reducing update search space. These interesting findings lead us to developing a new batch-dynamic method, called BatchHL+ , which can dynamize labelling for distance queries much more efficiently than existing work. We provide formal proofs for the correctness and minimality of BatchHL+ which are non-trivial and require a delicate analysis of patterns of interactions. Empirically, we have evaluated the performance of BatchHL+ on 15 real-world networks. The results show that BatchHL+ significantly outperforms the state-of-the-art methods with up to 3 orders of magnitude faster in reflecting updates of rapidly changing graphs for distance queries.
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Genomic data suggest parallel dental vestigialization within the xenarthran radiation
(The Mersenne Center, 2023-01-01) Emerling CA; Gibb GC; Tilak M-K; Hughes JJ; Kuch M; Duggan AT; Poinar HN; Nachman MW; Delsuc F
The recent influx of genomic data has provided greater insights into the molecular basis for regressive evolution, or vestigialization, through gene loss and pseudogenization. As such, the analysis of gene degradation patterns has the potential to provide insights into the evolutionary history of regressed anatomical traits. We specifically applied these principles to the xenarthran radiation (anteaters, sloths, armadillos), which is characterized by taxa with a gradation in regressed dental phenotypes. Whether the pattern among extant xenarthrans is due to an ancient and gradual decay of dental morphology or occurred repeatedly in parallel is unknown. We tested these competing hypotheses by examining 11 core dental genes in most living species of Xenarthra, characterizing shared inactivating mutations and patterns of relaxed selection during their radiation. Here we report evidence of independent and distinct events of dental gene loss in the major xenarthran subclades. First, we found strong evidence of complete enamel loss in the common ancestor of sloths and anteaters, suggested by the inactivation of five enamel-associated genes (AMELX, AMTN, MMP20, ENAM, ACP4). Next, whereas dental regression appears to have halted in sloths, presumably a critical event that ultimately permitted adaptation to an herbivorous lifestyle, anteaters continued losing genes on the path towards complete tooth loss. Echoes of this event are recorded in the genomes of all living anteaters, being marked by a 2-bp deletion in a gene critical for dentinogenesis (DSPP) and a putative shared 1-bp insertion in a gene linked to tooth retention (ODAPH). By contrast, in the two major armadillo clades, genes pertaining to the dento-gingival junction and amelogenesis appear to have been independently inactivated prior to losing all or some enamel. These genomic data provide evidence for multiple pathways and rates of anatomical regression, and underscore the utility of using pseudogenes to reconstruct evolutionary history when fossils are sparse