Understanding how the chloroplasts contribute to wheat susceptibility to rust fungi

Wheat rust fungi of the Pucciniaceae family, including Puccinia striiformis f. sp. tritici (Pst), pose a significant and sustained threat to global wheat production. Previous research has shown that yield losses associated with wheat rust infection primarily result from a reduction in the photosynthetic capacity of the plant. Additionally, it is widely understood that the chloroplasts are a hub for the synthesis and release of a number of pro-defence molecules including reactive oxygen species, calcium ions and salicylic acid, making them important organelles for coordinating the immune response. However, the molecular details of how chloroplast processes are manipulated during wheat infection with rust fungi remain to be elucidated. The main objective of this project was to investigate the ways in which wheat chloroplast processes contribute to rust susceptibility. To this aim, RNA-sequencing was carried out prior to the onset of this project on Pst-infected wheat tissue over time, revealing that many nuclear genes encoding chloroplast-localised proteins (NGCPs) had expression patterns that correlate with resistance to Pst at later stages of infection. I then selected the chloroplast metallopeptidase of unknown function (TaCPEP), which followed this pattern of expression, for further analyses. We obtained disruption mutants from a tetraploid and hexaploid Targeted Induced Local Lesions In Genomes (TILLING) population and showed that TaCPEP disruption increases susceptibility to both Pst and Magnaporthe oryzae pathotype triticum and may reduce chlorophyll content and chloroplast size, but without affecting the rate of assimilation. This thesis provides insight into the ways in which chloroplastic processes are altered during wheat infection with Pst and how one gene specifically may play a key role in susceptibility

Nanofibrous scaffolds releasing a small molecule BDNF-mimetic for the re-direction of endogenous neuroblast migration in the brain

9siBrain tissue engineering has the potential to harness existing elements of neurogenesis within the adult brain to overcome a microenvironment that is otherwise inhibitory to regeneration, especially following severe tissue damage. This study investigates the ability of electrospun poly ε-caprolactone (PCL) to re-direct the migratory pathway of endogenous neuroblasts from the disrupted subventricular zone (SVZ). A small molecule non-peptide ligand (BDNF-mimetic) that mimicked the trophic properties of brain-derived neurotrophic factor (BDNF) was incorporated into electrospun PCL scaffolds to improve neuroblast survival and promote neuroblast migration towards the implant. PCL scaffolds were able to support neuroblast infiltration and migration along the implant tract. In the presence of the BDNF-mimetic, neuroblasts were able to migrate towards the implant via the parenchyma, and their persistence within the implants was prolonged. In addition, the BDNF-mimetic improved implant integration and increased local neuronal plasticity by increasing neurite sprouting at the tissue-implant interface. SMI32+ neurites were observed inside scaffolds at 21 days but not 8 days post implantation, indicating that at least some of the infiltrated neuroblasts had differentiated into neurons.nonenoneFon, Deniece; Zhou, Kun; Ercole, Francesca; Fehr, Friederike; Marchesan, Silvia; Minter, Myles R.; Crack, Peter J.; Finkelstein, David I.; Forsythe, John SFon, Deniece; Zhou, Kun; Ercole, Francesca; Fehr, Friederike; Marchesan, Silvia; Minter, Myles R.; Crack, Peter J.; Finkelstein, David I.; Forsythe, John S

Faculty Entrustment and Resident Entrustability.

As the surgical education paradigm transitions to entrustable professional activities, a better understanding of the factors associated with resident entrustability are needed. Previous work has demonstrated intraoperative faculty entrustment to be associated with resident entrustability. However, larger studies are needed to understand if this association is present across various surgical training programs. To assess intraoperative faculty-resident behaviors and determine if faculty entrustment is associated with resident entrustability across 4 university-based surgical training programs. This cross-sectional study was conducted at 4 university-based surgical training programs from October 2018 to May 2022. OpTrust, a validated tool designed to assess both intraoperative faculty entrustment and resident entrustability behaviors independently, was used to assess faculty-resident interactions. A total of 94 faculty and 129 residents were observed. Purposeful sampling was used to create variation in type of operation performed, case difficulty, faculty-resident pairings, faculty experience, and resident training level. Observed resident entrustability scores (scale 1-4, with 4 indicating full entrustability) were compared with reported measures (faculty level, case difficulty, resident postgraduate year [PGY], resident gender, observation month) and observed faculty entrustment scores (scale 1-4, with 4 indicating full entrustment). Path analysis was used to explore direct and indirect effects of the predictors. Associations between resident entrustability and faculty entrustment scores were assessed by pairwise Pearson correlation coefficients. A total of 338 cases were observed. Cases observed were evenly distributed by faculty experience (1-5 years' experience: 67 [20.9%]; 6-14 years' experience: 186 [58%]; ≥15 years' experience: 67 [20.9%]), resident PGY (PGY 1: 28 [8%]; PGY 2: 74 [22%]; PGY 3: 64 [19%]; PGY 4: 40 [12%]; PGY 5: 97 [29%]; ≥PGY 6: 36 [11%]), and resident gender (female: 183 [54%]; male: 154 [46%]). At the univariate level, PGY (mean [SD] resident entrustability score range, 1.44 [0.46] for PGY 1 to 3.24 [0.65] for PGY 6; F = 38.92; P < .001) and faculty entrustment (2.55 [0.86]; R2 = 0.94; P < .001) were significantly associated with resident entrustablity. Path analysis demonstrated that faculty entrustment was associated with resident entrustability and that the association of PGY with resident entrustability was mediated by faculty entrustment at all 4 institutions. Faculty entrustment remained associated with resident entrustability across various surgical training programs. These findings suggest that efforts to develop faculty entrustment behaviors may enhance intraoperative teaching and resident progression by promoting resident entrustability

The branched-chain amino acid aminotransferase TaBCAT1 modulates aminoacid metabolism and positively regulates wheat rust susceptibility

National audienc