Whole-Genome Sequencing and Annotation of 10 Endophytic and Epiphytic Bacteria Isolated from Lolium arundinaceum

We report the whole-genome sequence and annotation of 10 endophytic and epiphytic bacteria isolated from the grass Lolium arundinaceum as part of a laboratory exercise in a Fundamentals of Plant Biochemistry and Pathology undergraduate course (BIOL403) at the Rochester Institute of Technology in Rochester, New York.

Morphological, environmental and management factors affecting nutritive value of tall fescue (Lolium arundinaceum)

The aim of this study was to quantify the relative importance of leaf age and leaf length on the dynamics of neutral detergent fibre (NDF), and 24-h in vitro digestibility of NDF (NDFD) and dry matter (DMD) of tall fescue (Lolium arundinaceum (Schreb) Darbysh.). Mini-swards were conditioned and used to conduct two experiments, the first with 4-cm plant stubble height in spring–summer 2009 and autumn–winter 2011, and the second with 4-cm or 10-cm plant stubble height in spring–summer 2011. Plants were harvested at consecutive leaf-appearance intervals to measure nutritive value up to the four-leaf stage. In parallel, leaf morphogenetic traits (appearance, elongation and lifespan) and sheath length of the successive leaves produced on marked tillers were measured. Leaf NDF contents remained stable with increasing leaf age and length but showed a marked variation across seasons. Leaf NDFD and DMD showed a consistent decrease with increasing leaf age and length, and irrespective of growing season or residual pasture height. The negative effect of leaf age and length on digestibility was related to variations in sheath tube length and associated differences in leaf appearance and elongation rates. These findings highlight the relevance of monitoring the sheath tube length as a complementary measure to leaf stage for further management of the NDFD and DMD of grass forages. Although the focus of this study was tall fescue swards, the same morphogenetic implications on forage nutritive value could apply to other temperate and tropical grass species; however, the testing of this hypothesis warrants carefully controlled investigations.

Managing fescue toxicosis through forage canopy, limestone application, and novel endophytes

Tall fescue [Lolium arundinaceum (Schreb.) Darbysh.] infected with the endophytic fungus Epichlo coenophiala [(Morgan-Jones and W. Gams) C.W. Bacon and Schardl, comb. nov.] produces ergovaline and other alkaloids responsible for fescue toxicosis, a livestock disorder. Cultivars re-infected with endophytes that do not produce toxic ergot alkaloids, referred to as "novel endophytes," have been used to alleviate the symptoms of fescue toxicosis. This research includes a series of experiments with the overall objective of identifying management practices that reduce fescue toxicosis in order to provide recommendations to Missouri farmers. The fist experiment examined the distribution of ergovaline and total ergot alkaloids throughout the vegetative canopy of tall fescue, and concluded that toxin concentrations are highest in the bottom 5 cm of the plant. The second experiment documented that applying limestone decreased ergovaline concentrations by at least 20 [mu]g kg[superscript -1] dry matter. The third experiment evaluated cattle preference among novel endophyte-infected tall fescue cultivars. This experiment concluded that one cultivar, 'BarOptima,' was grazed first and most frequently.

Leaf morphogenesis influences nutritive-value dynamics of tall fescue (Lolium arundinaceum) cultivars of different leaf softness

The objective of this study was to compare the dynamics of neutral detergent fibre (NDF), and the 24-h in-vitro digestibility of NDF (NDFD) and dry matter (DMD) in leaf blades of two tall fescue (Lolium arundinaceum (Schreb.) Darbysh.) cultivars of different leaf softness: a soft- and a tough-leaved cultivar. The experiment was conducted during the summer regrowth of three replicated, dense mini-swards per cultivar arranged in a completely randomised design, all grown under non-limiting water, nitrogen and phosphorus. Cultivars were harvested eight times over 14 weeks to measure morphogenetic traits and nutritive value in six predefined leaf-age categories (from growing to complete senescence). The leaf lifespan and leaf length of the first three successive leaves were measured on 30 marked tillers throughout the experiment. Following analysis of variance, linear regression models were fitted to describe variations of NDF, NDFD and DMD with increasing leaf age and leaf length. Similar leaf NDF contents were found for the two cultivars, which remained stable throughout the leaf lifespan and increased markedly during leaf senescence. Leaf NDFD and leaf DMD both declined with increasing leaf age and length for the two cultivars. However, owing to shorter leaf lifespan of the soft-leaved cultivar, this decline in leaf NDFD and leaf DMD was faster for the soft- than for the tough-leaved cultivar. These results suggest that the soft-leaved cultivar will require more frequent defoliations than the tough-leafed cultivar to prevent decreases in nutritive value.