Fungal endophytes that confer heat and drought tolerance to wheat

Fungal endophytes can improve plant tolerance to abiotic stresses such as heat and drought. I hypothesized that the six endophytic fungi SMCD 2204, 2206, 2208, 2210, 2214 and 2215 would promote heat and drought tolerance in wheat during both seed germination and at later developmental stages. The Vujanovic and Germida laboratories originally discovered these fungi from the roots of Saskatchewan grown wheat (Triticum turgidum L.). I assessed mycomediated enhancement of seed germination (mycovitality) including seedling performance, in vitro in terms of percent germination, seedling fresh weight, energy of germination (EG) and hydrothermal time (HTT) of germination. Endophytes SMCD 2206, 2210 and 2215 improved seedling heat or drought resistance, while SMCD 2204, 2208 and 2214 did not. In the greenhouse and phytotron, I evaluated the ability of the same six endophytes to enhance wheat tolerance for heat or drought stress by measuring photosynthetic stress (PS), carbon isotopic discrimination (∆), average seed weight (ASW), total seed weight (TSW) and the EG and percent germination of the F1 seeds produced. SMCD 2206, 2201 and 2215 increased performance of pot-grown wheat under heat and drought. Epigenetic modifications frequently involve changes in DNA methylation. Methyl-sensitive amplified polymorphism (MSAP) revealed that drought stressed wheat seedlings colonized with SMCD 2206 had DNA methylation patterns more similar to those of unstressed plants (with or without the endophyte) than to uncolonized drought stressed plants. Plant DNA sequences – similar to a cytochrome p450 EST and three transposable elements (TEs) – were differentially methylated between endophyte-free and endophyte colonized drought stressed plants. I tested the hypothesis that the endophyte-free progeny of SMCD 2206 colonized wheat grown in the phytotron or greenhouse under heat or drought stress would have heightened resistance for the same abiotic stressors to which their parents were exposed, compared to uninoculated first generation plants. Data on PS, ASW, TSW and ∆ showed that F2 plants incompletely inherited stress tolerance. This research demonstrated that fungal endophytes SMCD 2206, 2210 and 2215 improve wheat tolerance for heat and drought both in vitro and in pot studies. If field trials produce similar results, these isolates could be agriculturally important

In vivo study of the role of the cytoskeleton and fungal golgi in hyphal tip growth of Aspergillus nidulans

Filamentous fungi, such as Aspergillus nidulans, are composed of tubular, highly polarized, multinucleate cells called hyphae. Polar growth involves secretion specifically at the hyphal tip. Secretion involves intracellular transport and co-ordination of the cytoskeleton and the endomembrane system. Intracellular transport is likely mediated by cytoskeletal elements, which, in fungal cells consist primarily of actin and microtubules (MTs). An A. nidulans strain transformed with green fluorescent protein (GFP) tagged α-tubulin was utilized in the investigation of relationship between cytoplasmic MT arrays and hyphal growth rate. A. nidulans MTs were observed to be long and flexuous and to run roughly parallel to the long axis of hyphae. No correlation between relative MT abundance and hyphal growth rate was observed, although non-growing hyphae had a lower relative MT abundance than growing hyphae. Actin depolymerization decreased hyphal growth rate while MT depolymerization did not. MT stabilization increased hyphal growth rate. Ethanol, the solvent in which the MT and actin inhibitors were dissolved, increased both average overall growth rate and growth rate variability for individual hyphae. Taxol appeared to interact with irradiation to decreased growth rate during imaging. Golgi are involved in secretion and potentially in polar growth. An A. nidulans α-coatomer protein (COP)I homolog (α-COPI), tagged with GFP, was used to investigate the role(s) of fungal Golgi in polar growth. α-COPI-GFP co-localized with the known Golgi marker, α-2,6-sialyltransferase (ST), tagged with red fluorescent protein (RFP), in untreated hyphae. Based on this observation, I propose that α-COPI-GFP can be used as a proxy for fungal Golgi localization. Fungal Golgi were more abundant at hyphal tips than subapically. Fungal Golgi forward (tipward) velocity correlated with hyphal growth rate. Fungal Golgi forward velocity was, on average, approximately ten times greater than average hyphal growth rate. Actin depolymerization reduced fungal Golgi forward velocity while MT depolymerization did not. However, MT stabilization increased fungal Golgi forward velocity. Polymerized MTs do not appear to be essential for hyphal growth but do appear to be involved in hyphal growth rate variability. MTs also appear to play some role in the movement of fungal Golgi. The distribution and movement of fungal Golgi is clearly related to polarity

Rethinking pulse crop production in the era of Aphanomyces root rot

Non-Peer Reviewe

Intercropping as a disease management strategy

Non-Peer Reviewe

Physical activity referral to cardiac rehabilitation, leisure centre or telephone-delivered consultations in post-surgical people with breast cancer: a mixed methods process evaluation

BackgroundPhysical activity (PA) programmes effective under ‘research’ conditions may not be effective under ‘real-world’ conditions. A potential solution is to refer patients to existing PA community-based PA services.MethodsA process evaluation of referral of post-surgical patients with early-stage breast cancer to cardiac rehabilitation exercise classes, leisure centre with 3-month free leisure centre membership or telephone-deliveredPA consultations for 12 weeks. Quantitative data were collected about PA programme uptake and reach, patient engagement with the PA programme, delivery and fidelity and PA dose. Qualitative data were collected about patient experiences of taking part in the PA programmes. Audio-recorded qualitative interviews of participants about the programmes were analysed thematically. Quantitative data were reported descriptively using means and SD.ResultsIn Phase I, 30% (n = 20) of eligible patients (n = 20) consented, 85% (n = 17) chose referral to leisure centre, and 15% (n = 3) chose cardiac rehabilitation. In Phase II, 32% (n = 12) consented, 25% (n = 3) chose leisure centre and 75% (n = 9) chose telephone-delivered PA consultations. Walking at light intensity for about an hour was the most common PA. All Phase I participants received an induction by a cardiac rehabilitation physiotherapist or PA specialist from the leisure centre but only 50% of Phase II participants received an induction by a PA specialist from the leisure centre. Four themes were identified from qualitative interviews about programme choice: concerns about physical appearance, travel distance, willingness to socialise and flexibility in relation to doing PA. Four themes were identified about facilitators and barriers for engaging in PA: feeling better, feeling ill, weight management, family and friends.ConclusionsThe current community-based PA intervention is not yet suitable for a definitive effectiveness randomised controlled trial. Further work is needed to optimise PR programme reach, PA dose and intervention fidelity