The colonization of land by plants was a pivotal event in the history of the biosphere, and yet the underlying evolutionary features and innovations of the first land plant ancestors are not well understood. Here we present the genome sequence of the unicellular alga Penium margaritaceum, a member of the Zygnematophyceae, the sister lineage to land plants. The P. margaritaceum genome has a high proportion of repeat sequences, which are associated with massive segmental gene duplications, likely facilitating neofunctionalization. Compared with earlier diverging plant lineages, P. margaritaceum has uniquely expanded repertoires of gene families, signaling networks and adaptive responses, supporting its phylogenetic placement and highlighting the evolutionary trajectory towards terrestrialization. These encompass a broad range of physiological processes and cellular structures, such as large families of extracellular polymer biosynthetic and modifying enzymes involved in cell wall assembly and remodeling. Transcriptome profiling of cells exposed to conditions that are common in terrestrial habitats, namely high light and desiccation, further elucidated key adaptations to the semi-aquatic ecosystems that are home to the Zygnematophyceae. Such habitats, in which a simpler body plan would be advantageous, likely provided the evolutionary crucible in which selective pressures shaped the transition to land.Earlier diverging charophyte lineages that are characterized by more complex land plant-like anatomies have either remained exclusively aquatic, or developed alternative life styles that allow periods of desiccation.
Insects have been proposed as a high-quality, efficient and sustainable dietary protein source. The present study evaluated the protein quality of a selection of insect species. Insect substrates were housefly pupae, adult house cricket, yellow mealworm larvae, lesser mealworm larvae, Morio worm larvae, black soldier fly larvae and pupae, six spot roach, death's head cockroach and Argentinean cockroach. Reference substrates were poultry meat meal, fish meal and soyabean meal. Substrates were analysed for DM, N, crude fat, ash and amino acid (AA) contents and for in vitro digestibility of organic matter (OM) and N. The nutrient composition, AA scores as well as in vitro OM and N digestibility varied considerably between insect substrates. For the AA score, the first limiting AA for most substrates was the combined requirement for Met and Cys. The pupae of the housefly and black soldier fly were high in protein and had high AA scores but were less digestible than other insect substrates. The protein content and AA score of house crickets were high and similar to that of fish meal; however, in vitro N digestibility was higher. The cockroaches were relatively high in protein but the indispensable AA contents, AA scores and the in vitro digestibility values were relatively low. In addition to the indices of protein quality, other aspects such as efficiency of conversion of organic side streams, feasibility of mass-production, product safety and pet owner perception are important for future dog and cat food application of insects as alternative protein source.
Dioecious plant species represent an important component of terrestrial ecosystems. Yet, little is known about sexspecific responses to drought and elevated temperatures. Populus cathayana Rehd, which is a dioecious, deciduous tree species, widely distributed in the northern, central and southwestern regions of China, was employed as a model species in our study. In closed-top chamber experiments, sex-specific morphological, physiological and biochemical responses of P. cathayana to drought and different elevated temperatures were investigated. Compared with the controls, drought significantly decreased the growth and the net photosynthesis rate (A), and increased the intrinsic water use efficiency (WUEi), carbon isotope composition (d
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