Research Notes : Brazil : Effects of seed color on seed deterioration

It has been noted (Dassou and Kueneman, 1984) that soybean varieties with colored seed frequently show tolerance to seed deterioration. In Brazil, naturally occurring, colored-seeded mutants of four soybean lines have been found. The existence of these near-isolines provided an opportunity to assess the role of seed color on seed deterioration in similar genetic background

Research Notes : Constraints in using seed leachate characteristics to estimate seed vigor for varietal seed keeping quality comparisons in soybeans

Summary : Recent research has provided good evidence that characteris-tics of seed leachate, such as electrical conductivity and optical density, can be used as a measure of relative vigor for different seed lots of the same variety. Because plant breeders selecting for better seed longevity must make comparisons among varieties, studies were conducted to determine if leachate characteristics could be used to compare seed vigor among varieties that vary in seed size, seed color and seed coat permeability. Seeds of a yellow-seeded variety (TGm 579) and a black-seeded variety (TGM 618) were soaked with seed coats either intact or removed

Research Notes : Brazil : Varietal differences in soybeans for resistance to physical damage of seed

Introduction: Production of quality soybean seed is frequently problematic in the tropics (Jalani et al., 1982; Khaleque, 1982; Mercer-Quarshie and Nsowah, 1975; Ndimande et al., 1981; Paschal and Ellis, 1978). In general, loss of seed vigor is associated with seed deterioration in the field prior to harvest (Ellis and Sinclair, 1976; Green and Finnel, 1968; Ndimande et al., 1981; Paschal and Ellis, 1978; Potts et al., 1978) and with deterioration in storage (Kueneman, 1982; Minor and Paschal, 1982; Ndimande et al., 1981; Tongdee, 1982; Wien and Kueneman, 1981); seed deterioration is accelerated by hot, humid environments. While there is considerable scope for development of genotypes less prone to deterioration (Dassou and Kueneman, 1984; Kueneman, 1982, 1983; Paschal and Ellis, 1978; Wien and Kueneman, 1981), it is generally recommended that soybeans grown for seed should be sown such that they mature under dry environmental conditions. Often in the tropics, seed production must take place in the dry off-season under irrigation, which increases costs of production

Genetic manipulation of crop plants to enhance integrated nutrient management in cropping systems— 1. Phosphorus: proceedings of an FAO-ICRISAT Expert Consultancy Workshop 15—18 Mar 1994

This Workshop forms part of an overall endeavor to establish a global consortium of researchers focusing their efforts on improving the ability of crop plants to acquire phosphorus, particularly through sources from which it is only sparingly available. These sources include bound forms of soil phosphorus and such fertilizers or amendments as rock phosphate. This volume explains the overall procedures followed, presents the formal papers prepared for the Workshop, and highlights the outcome of the deliberations in the form of a preliminary draft proposal for a global project. A background paper covers the possibilities of favorably manipulating phosphorus acquisition, which include modifying root absorption area by improving rooting characteristics or mycorrhizal associations, manipulating ion absorption mechanisms, and modifying the rhizosphere through root exudations or effects of microorganisms. Position papers prepared by invited specialists examine in detail the prospects for favorable manipulation of specific components of phosphorus acquisition. During the Workshop, research areas with prospects for impact on agriculture in the medium term were identified and appropriate outputs and activities proposed. The promising research areas chosen were modification of root morphology, manipulation of root exudates, enhancement of mycorrhizal effects through crop management practices, and optimization of cropping systems approaches. The Workshop laid the foundation for subsequent activities of formulating detailed project proposals and soliciting support from potential donors for the proposed global consortium

Next steps for conservation agriculture.

The origins, history, and recent advances in Conservation Agriculture (CA) are reported. CA is now practiced worldwide on some 200 million hectares, important for mitigating climate change and ensuring food security. Its bedrock is Zero Tillage (ZT) with crop rotation and retention of crop residues. CA approaches Or-19 ganic Agriculture (OA) when coupled to biological control providing opportunity for OA to become truly sustainable. Ley Farming (LF) and agroforestry with ZT are important for carbon sequestration and land use intensification. Hidden cost: each ton of carbon immobilizes 83 kg of N, 29 kg of P, and 14 kg of S. Industry-backed Regenerative Agriculture (RA) variants have no scientific definition, but generally adopt CA. Sustainable, profitable, and compatible new technologies are emerging and CA needs to embrace them to present a holistic, sustainable package to the farmer. How? A single definition for agricultural sustainability via a multi-stakeholder world congress would standardize certification and de-confuse the market. RA describes exactly what CA does for soil health and all farmers need to unite around a new "Combined Regenerative Agriculture" (CRA) to lobby for adequate payments for environmental services. Expansion of CA is critical for world sustainability. Many gaps and constraints exist, especially for smallholders

Natural experiments and long-term monitoring are critical to understand and predict marine host-microbe ecology and evolution

© The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Leray, M., Wilkins, L. G. E., Apprill, A., Bik, H. M., Clever, F., Connolly, S. R., De Leon, M. E., Duffy, J. E., Ezzat, L., Gignoux-Wolfsohn, S., Herre, E. A., Kaye, J. Z., Kline, D. I., Kueneman, J. G., McCormick, M. K., McMillan, W. O., O’Dea, A., Pereira, T. J., Petersen, J. M., Petticord, D. F., Torchin, M. E., Thurber, R. V., Videvall, E., Wcislo, W. T., Yuen, B., Eisen, J. A. . Natural experiments and long-term monitoring are critical to understand and predict marine host-microbe ecology and evolution. Plos Biology, 19(8), (2021): e3001322, https://doi.org/10.1371/journal.pbio.3001322.Marine multicellular organisms host a diverse collection of bacteria, archaea, microbial eukaryotes, and viruses that form their microbiome. Such host-associated microbes can significantly influence the host’s physiological capacities; however, the identity and functional role(s) of key members of the microbiome (“core microbiome”) in most marine hosts coexisting in natural settings remain obscure. Also unclear is how dynamic interactions between hosts and the immense standing pool of microbial genetic variation will affect marine ecosystems’ capacity to adjust to environmental changes. Here, we argue that significantly advancing our understanding of how host-associated microbes shape marine hosts’ plastic and adaptive responses to environmental change requires (i) recognizing that individual host–microbe systems do not exist in an ecological or evolutionary vacuum and (ii) expanding the field toward long-term, multidisciplinary research on entire communities of hosts and microbes. Natural experiments, such as time-calibrated geological events associated with well-characterized environmental gradients, provide unique ecological and evolutionary contexts to address this challenge. We focus here particularly on mutualistic interactions between hosts and microbes, but note that many of the same lessons and approaches would apply to other types of interactions.Financial support for the workshop was provided by grant GBMF5603 (https://doi.org/10.37807/GBMF5603) from the Gordon and Betty Moore Foundation (W.T. Wcislo, J.A. Eisen, co-PIs), and additional funding from the Smithsonian Tropical Research Institute and the Office of the Provost of the Smithsonian Institution (W.T. Wcislo, J.P. Meganigal, and R.C. Fleischer, co-PIs). JP was supported by a WWTF VRG Grant and the ERC Starting Grant 'EvoLucin'. LGEW has received funding from the European Union’s Framework Programme for Research and Innovation Horizon 2020 (2014-2020) under the Marie Sklodowska-Curie Grant Agreement No. 101025649. AO was supported by the Sistema Nacional de Investigadores (SENACYT, Panamá). A. Apprill was supported by NSF award OCE-1938147. D.I. Kline, M. Leray, S.R. Connolly, and M.E. Torchin were supported by a Rohr Family Foundation grant for the Rohr Reef Resilience Project, for which this is contribution #2. This is contribution #85 from the Smithsonian’s MarineGEO and Tennenbaum Marine Observatories Network.

Genetic variability and ontogeny predict microbiome structure in a disease-challenged montane amphibian

Amphibian populations worldwide are at risk of extinction from infectious diseases, including chytridiomycosis caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd). Amphibian cutaneous microbiomes interact with Bd and can confer protective benefits to the host. The composition of the microbiome itself is influenced by many environment- and host-related factors. However, little is known about the interacting effects of host population structure, genetic variation and developmental stage on microbiome composition and Bd prevalence across multiple sites. Here we explore these questions in Amietia hymenopus, a disease-affected frog in southern Africa. We use microsatellite genotyping and 16S amplicon sequencing to show that the microbiome associated with tadpole mouthparts is structured spatially, and is influenced by host genotype and developmental stage. We observed strong genetic structure in host populations based on rivers and geographic distances, but this did not correspond to spatial patterns in microbiome composition. These results indicate that demographic and host genetic factors affect microbiome composition within sites, but different factors are responsible for host population structure and microbiome structure at the between-site level. Our results help to elucidate complex within- and among- population drivers of microbiome structure in amphibian populations. That there is a genetic basis to microbiome composition in amphibians could help to inform amphibian conservation efforts against infectious diseases

Using “omics” and integrated multi-omits approaches to guide probiotic selection to mitigate chytridiomycosis and other emerging infectious diseases

Emerging infectious diseases in wildlife are responsible for massive population declines. In amphibians, chytridiomycosis caused by Batrachochytrium dendrobatidis, Bd, has severely affected many amphibian populations and species around the world. One promising management strategy is probiotic bioaugmentation of antifungal bacteria on amphibian skin. In vivo experimental trials using bioaugmentation strategies have had mixed results, and therefore a more informed strategy is needed to select successful probiotic candidates. Metagenomic, transcriptomic, and metabolomic methods, colloquially called “omics,” are approaches that can better inform probiotic selection and optimize selection protocols. The integration of multiple omic data using bioinformatic and statistical tools and in silico models that link bacterial community structure with bacterial defensive function can allow the identification of species involved in pathogen inhibition. We recommend using 16S rRNA gene amplicon sequencing and methods such as indicator species analysis, the Kolmogorov–Smirnov Measure, and co-occurrence networks to identify bacteria that are associated with pathogen resistance in field surveys and experimental trials. In addition to 16S amplicon sequencing, we recommend approaches that give insight into symbiont function such as shotgun metagenomics, metatranscriptomics, or metabolomics to maximize the probability of finding effective probiotic candidates, which can then be isolated in culture and tested in persistence and clinical trials. An effective mitigation strategy to ameliorate chytridiomycosis and other emerging infectious diseases is necessary; the advancement of omic methods and the integration of multiple omic data provide a promising avenue toward conservation of imperiled species

A communal catalogue reveals Earth’s multiscale microbial diversity

Our growing awareness of the microbial world’s importance and diversity contrasts starkly with our limited understanding of its fundamental structure. Despite recent advances in DNA sequencing, a lack of standardized protocols and common analytical frameworks impedes comparisons among studies, hindering the development of global inferences about microbial life on Earth. Here we present a meta-analysis of microbial community samples collected by hundreds of researchers for the Earth Microbiome Project. Coordinated protocols and new analytical methods, particularly the use of exact sequences instead of clustered operational taxonomic units, enable bacterial and archaeal ribosomal RNA gene sequences to be followed across multiple studies and allow us to explore patterns of diversity at an unprecedented scale. The result is both a reference database giving global context to DNA sequence data and a framework for incorporating data from future studies, fostering increasingly complete characterization of Earth’s microbial diversity