Effect of one or more microorganisms on the yield components of upland rice under greenhouse conditions

The use of beneficial microorganisms is an important strategy to improve rice production in a sustainable way. The study was carried out to determine the effect of single and combined beneficial microorganism on the development of upland rice. The experiment was performed in greenhouse and arranged in a completely randomized design with 29 treatments and 4 replications. Treatments consisted of rice seeds cultivar BRS A501 CL treated with single and combined multifunctional microorganisms (1 (Serratia marcescens), 2 (Bacillus toyonensis), 3 (Phanerochaete australis), 4 (Trichoderma koningiopsis), 5 (Azospirillum brasilense), 6 (Azospirillum sp.), 7 (Bacillus sp.), 8 to 28 (combination of all these microorganisms in pairs) and 29 (control)). Inoculation of upland rice with sole and combined microorganism on upland rice increased the roots and shoots development, yield components and grain yield of upland rice. The combinations of Bacillus sp. (BRM 63573) and A. brasilense (AbV5), Azospirillum sp. (BRM 63574) + B. toyonensis (BRM 32110) and Phanerochaete australis (BRM 62389) + Serratia marcenscens (BRM 32114) led to improved roots and shoots development; increased number of panicles and grains per pot, 1000 grains weight and grain yield of rice plants. Besides, the combinations allow helped in increased accumulation of nutrients in roots, shoots and grains of rice plants.

Disclosing the native blueberry rhizosphere community in Portugal-an integrated metagenomic and isolation approach

Backgorund

The production of red fruits, such as blueberry, has been threatened by several stressors from severe periods of drought, nutrient scarcity, phytopathogens, and costs with fertilization programs with adverse consequences. Thus, there is an urgent need to increase this crop's resilience whilst promoting sustainable agriculture. Plant growth-promoting microorganisms (PGPMs) constitute not only a solution to tackle water and nutrient deficits in soils, but also as a control against phytopathogens and as green compounds for agricultural practices.

Methods

In this study, a metagenomic approach of the local fungal and bacterial community of the rhizosphere of Vaccinium corymbosum plants was performed. At the same time, both epiphytic and endophytic microorganisms were isolated in order to disclose putative beneficial native organisms.

Results

Results showed a high relative abundance of Archaeorhizomyces and Serendipita genera in the ITS sequencing, and Bradyrhizobium genus in the 16S sequencing. Diversity analysis disclosed that the fungal community presented a higher inter-sample variability than the bacterial community, and beta-diversity analysis further corroborated this result. Trichoderma spp., Bacillus spp., and Mucor moelleri were isolated from the V. corymbosum plants.

Discussion

This work revealed a native microbial community capable of establishing mycorrhizal relationships, and with beneficial physiological traits for blueberry production. It was also possible to isolate several naturally-occurring microorganisms that are known to have plant growth-promoting activity and confer tolerance to hydric stress, a serious climate change threat. Future studies should be performed with these isolates to disclose their efficiency in conferring the needed resilience for this and several crops.

Plant-archaea relationships: a potential means to improve crop production in arid and semi-arid regions

Crop production in arid and semi-arid regions of the world is limited by several abiotic factors, including water stress, temperature extremes, low soil fertility, high soil pH, low soil water-holding capacity, and low soil organic matter. Moreover, arid and semi-arid areas experience low levels of rainfall with high spatial and temporal variability. Also, the indiscriminate use of chemicals, a practice that characterizes current agricultural practice, promotes crop and soil pollution potentially resulting in serious human health and environmental hazards. A reliable and sustainable alternative to current farming practice is, therefore, a necessity. One such option includes the use of plant growth-promoting microbes that can help to ameliorate some of the adverse effects of these multiple stresses. In this regard, archaea, functional components of the plant microbiome that are found both in the rhizosphere and the endosphere may contribute to the promotion of plant growth. Archaea can survive in extreme habitats such as areas with high temperatures and hypersaline water. No cases of archaea pathogenicity towards plants have been reported. Archaea appear to have the potential to promote plant growth, improve nutrient supply and protect plants against various abiotic stresses. A better understanding of recent developments in archaea functional diversity, plant colonizing ability, and modes of action could facilitate their eventual usage as reliable components of sustainable agricultural systems. The research discussed herein, therefore, addresses the potential role of archaea to improve sustainable crop production in arid and semi-arid areas.

Seed coating with beneficial microorganisms for precision agriculture

Seed coating is a technique of covering seeds with adhesive agents to improve seed performance and plant establishment while reducing production cost. To meet the needs of development of precision agriculture, seed coating has been widely used in agriculture as an effective means to alleviate biotic and abiotic stresses, thus enhancing crop growth, yield, and health. Plant growth promoting microorganisms (PGPM) are recognized as essential contributors to improving agricultural productivity via direct application to the rhizosphere and plant tissues, or seed inoculation. However, during conventional inoculation processes, several factors such as insufficient microbial survival, hindrance in the application of biocontrol inocula to the seeds and exposure to unsuitable temperature and light in subsequent seed storage, force us to explore efficient and reliable microbial application tools. Recently, biological seed coating with PGPM is proposed as an alternative to conventional seed treatment (such as fertilizer and protection products) due to its ecological safety and socio-economic aspects. In this review, microbial seed coating technology and its contribution to sustainable precision agriculture are well discussed and highlighted in the extensive table and elaborate schematic drawings.

Bioprospecting from plant waste composting: Actinobacteria against phytopathogens producing damping-off

Strains isolated during composting processes of plant waste, and identified as Actinobacteria, proved to be significant producers of compounds that actively participate in the control of phytopathogens, such as those that cause Damping-off disease. Although most of the actinomycetes analyzed showed to be antagonistic strains against common phytopathogens, only some 30% proved to be capable of producing bioactive substances, such as siderophores, salicylic acid, chitinase enzymes or cyanide, so that antibiosis could be considered the most probable antagonistic mechanism for a high proportion of the strains investigated. 6% of the microorganisms identified in this work, were selected as potential strains to be investigated in depth, since they further stimulated plant growth (germination index tests greater than 100%). Microbacteriaceae was one of the most prominent families.