Hey readers!

A new review from Embrapa Soja traces two decades of bacterial inoculants in Brazilian maize and shows where farmers have adopted them most. Three bacteria from wheat landraces reduced Bipolaris disease as the root microbiome changed, and an Australian study found that mycorrhizal fungi behave differently in combination than on their own.

On the industry side, Rovensa Next moved Trichoderma production from rice to liquid fermentation and reports cutting cultivation time by about half.

Let’s dive in.

The first commercial inoculant based on Azospirillum brasilense strains Ab-V5 and Ab-V6 reached the Brazilian market in 2009. A new review by researchers from Embrapa Soja, including Mariangela Hungria, examines two decades of scientific development, field performance and commercial adoption.

A. brasilense inoculants were applied to approximately 10 million hectares of Brazilian maize in the 2025/26 season. Adoption reached 50.9% in the second maize crop, known as safrinha, compared with 28.4% in the summer crop. The authors suggest that greater exposure to water deficit and lower nitrogen topdressing rates help explain why inoculation has become more widespread in the second crop.

A meta-analysis covering 103 field trials at 54 locations found an average grain yield increase of 5.4% with Ab-V5 and Ab-V6. Another research network, involving 30 experiments at 13 sites over ten years, reported a 3.1% average increase. In that network, inoculated maize receiving 75% of the recommended topdressing nitrogen achieved yields statistically equivalent to uninoculated maize receiving the full rate.

The review also separates microbial performance from mechanism of action. The authors report that the genome of Methylobacterium symbioticum lacks the core nif genes required for any known nitrogenase, which leaves claims of biological nitrogen fixation for this species without support. They attribute its effects on plants to other traits described for the genus, notably cytokinin production.

Brazil’s experience illustrates what sustained research, field validation and technology transfer can achieve for microbial inoculants.

Researchers at Embrapa Environment and the University of São Paulo selected three bacteria from the rhizosphere of Turkish and Iranian wheat landraces grown in Brazilian agricultural soil: Streptomyces virginiae CMAA1738, Paenibacillus ottowii CMAA1739 and Pseudomonas inefficax CMAA1741. All three inhibited Bipolaris sorokiniana on plates. Each strain was then tested on its own in wheat grown in field soil inside a climate room, applied to the seed and again at the stem base after infection, and disease severity fell by about 60% compared with plants given the pathogen alone.

Less disease, however, did not consistently mean less pathogen DNA. A DNA marker for the fungus rose in some bacterial treatments and showed no significant link with how much disease the plants developed.

The more interesting change was in the microbial community around the roots. Inoculation reshaped it and, according to the authors, restored the diversity of plant growth-promoting genes and gene clusters for secondary metabolites that infection had reduced.

Strains like these may protect wheat partly through the community they shape around the roots, which is why pathogen DNA alone may not be enough to judge whether an inoculant is working.

Researchers led by Western Sydney University inoculated tomato with five arbuscular mycorrhizal fungi, alone and in six combinations, and then exposed the plants to the root pathogen Rhizoctonia solani. Cameras photographed every plant daily in a glasshouse phenotyping facility to track growth before and after infection.

The combinations rarely behaved as the single isolates predicted. Without the pathogen, only Funneliformis mosseae paired with Gigaspora margarita grew more than either fungus alone. The mix of all five isolates, and the pairing of the two isolates best known for disease protection, grew closer to the weakest single isolate.

Five of the six combinations reduced the biomass loss caused by R. solani, compared with plants without mycorrhizal fungi. G. margarita and Scutellospora calospora, two isolates that had failed to protect tomato on their own in the team’s earlier work, brought infected plants to biomass levels similar to those of uninfected plants when combined. The F. mosseae and G. margarita pairing, the best for growth, offered no protection, and plant growth nearly stopped after infection.

Performance of each fungus alone did not predict how a mixture would behave, so mycorrhizal consortia need to be tested as combinations. The authors note that the findings could be relevant for glasshouse crops such as tomato, where mycorrhizal inoculants can be used in a more targeted way.

Rovensa Next has developed a liquid fermentation platform for producing Trichoderma koningiopsis, replacing cereal-based solid cultivation with a process designed for greater control and reproducibility. The strain was isolated by SRM Brazil Technology, which has partnered on the project since the start.

Developed by the company’s R&D team in Brazil, the technology combines liquid cultivation with separation, drying and formulation stages. According to Rovensa Next, the new process reduces cultivation time by approximately 50% while improving productivity and minimizing losses during downstream processing.

The company reports that the platform has been developed with semi-industrial scale-up in mind and has undergone field validation, with agronomic performance comparable to positive controls.

Liquid fermentation is already widely used for other microorganisms. The company describes its advance as adapting that process specifically for fungal spore production.

The project took first place in the Innovative Project category at the São Paulo stage of Brazil’s IEL Talent Awards and will compete in the national final in Curitiba in December. Rovensa Next says the platform could also be applied to other fungi of agricultural interest.