• A comparative study on seed physiology and germination requirements for 15 species of Eucalyptus

      Afroze, Farhana; Douglas, Gerry C.; Grogan, Helen; Department of Agriculture, Food and the Marine; 15/S/759 (Springer Science and Business Media LLC, 2021-09-23)
      Seed physiology of 15 Eucalyptus species of interest for cut foliage plantations was unknown and therefore evaluated. The viability and vigour of seeds and germination potential of 15 Eucalyptus species was determined by using a tetrazolium (TZ) staining test, and the results were compared to a germination test. In a separate experiment, seeds of each lot were subjected to either 0 or 4-week cold stratification at 4 ± 1 °C to investigate their potential stratification requirement. After stratification, seeds were then allowed to germinate at 22 ± 1 °C with 16 h lighting per day for 36 days. Seed viability and vigour were checked by evaluating % root, cotyledon and first true leaves emergence, and the speed of emergence, in the germination test. The germination percentages varied with the species. Seed stratification with the interaction of seed species lots significantly affected both viability and vigour. The seed viability of the different species ranged from 9 to 100% and 2 to 100%, for the TZ test and germination test, respectively, with a high correlation (R2 = 0.89) between the two. Physiology tests revealed that cold stratification of seed was not required for the 15 species to maximise their germination potential and growth in Irish and British climate.
    • Fertiliser characteristics of stored spent mushroom substrate as a sustainable source of nutrients and organic matter for tillage, grassland and agricultural soils

      Velusami, B.; Jordan, S.N.; Curran, T.; Grogan, Helen; Teagasc Walsh Scholarship Programme (Teagasc, 2021-05-12)
      Spent mushroom substrate (SMS) is an organic manure that can be used with advantage in agriculture. Under European Union (EU) (Good Agricultural Practice for Protection of Waters) Regulations, SMS cannot be applied to land over the winter months and must be stored on concrete surfaces, either covered or uncovered, to prevent nutrient-rich runoff seeping into groundwater. Spent mushroom substrate at four storage facilities, two covered and two uncovered, was analysed for physical and chemical characteristics after storage for up to 12 mo. Significant differences (P<0.05) were identified for all parameters across the four sites, except for pH, but there were no consistent differences that correlated with uncovered or covered storage conditions. The content of nitrogen (N) and manganese (Mn) was significantly lower in uncovered SMS, while the content of iron (Fe) and copper (Cu) was significantly higher. The chemical nitrogen-phospous-potassium (NPK) fertiliser equivalent value of SMS, when applied at a rate of 10 t/ha, was between €105 and €191 per hectare. Nitrogen-phospous-potassium concentrations per kg wet weight were all higher in SMS that was stored under cover, meaning higher chemical fertiliser savings are possible. The high pH of stored SMS (7.8–8.1) means it could be used with good effect on acid soils instead of ground limestone. The low bulk density of SMS (0.545–0.593 g/cm3) makes it an ideal amendment to soils to improve soil structure and quality. There is some variability in the nutrient content of SMS from different sources, so it is advisable to get the material analysed when including in nutrient management plans.
    • Proteomic investigation of interhyphal interactions between strains of Agaricus bisporus

      O’Connor, Eoin; Owens, Rebecca A.; Doyle, Sean; Amini, Aniça; Grogan, Helen; Fitzpatrick, David; Teagasc Walsh Fellowship Programme; Science Foundation Ireland; 10564231; SFI 12/RI/2346(3) (Elsevier BV, 2020-06)
      Hyphae of filamentous fungi undergo polar extension, bifurcation and hyphal fusion to form reticulating networks of mycelia. Hyphal fusion or anastomosis, a ubiquitous process among filamentous fungi, is a vital strategy for how fungi expand over their substrate and interact with or recognise self- and non-self hyphae of neighbouring mycelia in their environment. Morphological and genetic characterisation of anastomosis has been studied in many model fungal species, but little is known of the direct proteomic response of two interacting fungal isolates. Agaricus bisporus, the most widely cultivated edible mushroom crop worldwide, was used as an in vitro model to profile the proteomes of interacting cultures. The globally cultivated strain (A15) was paired with two distinct strains; a commercial hybrid strain and a wild isolate strain. Each co-culture presented a different interaction ranging from complete vegetative compatibility (self), lack of interactions, and antagonistic interactions. These incompatible strains are the focus of research into disease-resistance in commercial crops as the spread of intracellular pathogens, namely mycoviruses, is limited by the lack of interhyphal anastomosis. Unique proteomic responses were detected between all co-cultures. An array of cell wall modifying enzymes, plus fungal growth and morphogenesis proteins were found in significantly (P < 0.05) altered abundances. Nitrogen metabolism dominated in the intracellular proteome, with evidence of nitrogen starvation between competing, non-compatible cultures. Changes in key enzymes of A. bisporus morphogenesis were observed, particularly via increased abundance of glucanosyltransferase in competing interactions and certain chitinases in vegetative compatible interactions only. Carbohydrate-active enzyme arsenals are expanded in antagonistic interactions in A. bisporus. Pathways involved in carbohydrate metabolism and genetic information processing were higher in interacting cultures, most notably during self-recognition. New insights into the differential response of interacting strains of A. bisporus will enhance our understanding of potential barriers to viral transmission through vegetative incompatibility. Our results suggest that a differential proteomic response occurs between A. bisporus at strain-level and findings from this work may guide future proteomic investigation of fungal anastomosis.
    • Prunus laurocerasus - A crop walkers guide to pests and diseases

      Horticulture Development Department; Grogan, Helen; McGuinness, Brian; Whelton, Andy; Baars, Jan-Robert; Department of Agriculture, Food and the Marine; 15S759 (Teagasc, 2021)
      The large glossy leaves of Prunus laurocerasus are affected by a variety of problems including pests, diseases and nutrition. The most common issue is commonly referred to as ‘shothole’ due to the nature of the disease symptoms and its’ resemblance to shotgun damage. The causal agents of ‘shothole disease’ vary considerably and this will affect how you approach your disease management strategy.
    • Tackling mushroom disease control in an environmentally conscious world

      Grogan, Helen (2021)
      The mushroom industry, like all of agriculture worldwide, is facing the impact of climate change as well as consumers’ desires to address it though modifying what they purchase so as to be as environmentally friendly as possible. At the 2021 ISMS Congress, Dr. Helen Grogan presented the state of the changing climate and opportunities for Integrated Pest Management in the mushroom industry.