Colloquium with Juliana Erika de Carvalho Teixeira Yassitepe and Sylvia Morais de Sousa Tinôco

On 03 March 2026, Juliana Erika de Carvalho Teixeira Yassitepe and Sylvia Morais de Sousa Tinôco (Embrapa and Genomics for Climate Change Research Center, Brazil) will present insights into their current research as part of the Halle Plant Science Colloquium (HPSC).

Speakers: Juliana Erika de Carvalho Teixeira Yassitepe and Sylvia Morais de Sousa Tinôco (Embrapa and Genomics for Climate Change Research Center, Brazil)
Title: 1. Maize transformation and phenotyping for drought stress; 2. Plant-soil-microorganism interactions: enhancing phosphorus acquisition of maize and sorghum in tropical soils

Date: Tuesday, 03 March 2026
Time: 12:30 pm
Location: Lecture hall (GHS) of Biochemistry, Kurt-Mothes-Straße 3 (Weinberg Campus), 06120 Halle (Saale)

Abstracts

1.Maize transformation and phenotyping for drought stress

Developing drought- and heat-tolerant maize is critical to sustaining crop productivity under climate change. At the Genomics for Climate Change Research Center (GCCRC) in Campinas, Brazil, our research focuses on overexpressing and knocking out candidate genes—particularly those with unknown functions—to deepen our understanding of maize tolerance mechanisms to drought and heat stress. We established a maize transformation pipeline in 2019 using Agrobacterium tumefaciens-mediated transformation of immature zygotic embryos from the temperate inbred line B104. Over time, we significantly increased transformation efficiency by implementing ternary vectors and morphogenic regulator (MR) genes. These optimizations enabled the efficient transformation and genome editing of tropical maize lines, surpassing the transformation performance of B104. Seasonal variation remains a key factor influencing embryo quality and transformation efficiency, as embryo production is reduced during colder months. To mitigate this limitation, we are testing a leaf-based transformation protocol that has shown promising results for year-round transformation. To evaluate the resulting transgenic events, we developed an affordable digital phenotyping platform for controlled-environment drought assays, and we use unmanned aerial systems (UAS) equipped with RGB and multispectral cameras to monitor and predict plant responses throughout the crop cycle in the field. Together, these advances demonstrate a comprehensive, scalable pipeline – from gene manipulation to high-throughput phenotyping and predictive modeling – that accelerates the discovery and validation of genes conferring drought and heat resilience in maize. This integrated approach not only enhances our understanding of stress tolerance mechanisms but also provides practical tools for developing climate-resilient maize germplasm adapted to tropical environments.

Marginal soil fertility, soil acidity, aluminum toxicity, and low nutrient levels, especially phosphorus (P), are major limiting factors to cereal production in highly weathered tropical soils. Chemical fertilizers have been instrumental in the intensification of agriculture. However, if applied in excess, they can contaminate the environment, and can significantly increase the production cost. Cereals receive almost half of the world’s phosphate fertilizer applications. Therefore, plant P use efficiency (PUE) should be increased, aiming a more sustainable agriculture. One alternative is to use less soluble P sources associated that are more efficient in PUE. In addition, the symbiosis between P with plant genotypes solubilizing bacteria and/or arbuscular mycorrhizal fungi and plants can contribute to increase the acquisition of this nutrient and promote the growth of cultivated plants. Other factor essential for the plants to more effectively forage for P in the soil, increasing P acquisition under low soil P availability is the root system architecture (RSA) alterations leading to longer and thinner ageotropic lateral roots in the topsoil (where P levels are highest). To date, there are not many genes that directly link root morphology and P acquisition, particularly in crop species cultivated in soils with low-P availability. A receptor-like cytoplasmic kinase gene named PHOSPHORUS-STARVATION TOLERANCE 1 (PSTOL1) is the first gene candidate to P efficiency (tolerance to low soil P) identified. This gene is responsible for a major quantitative trait locus for rice root P uptake. We have identified and characterized the homologous of this gene in maize and sorghum. In parallel, we showed that the most productive maize and sorghum genotypes have higher root angle and area, increasing foraging on the soil surface and P acquisition. Moreover, we showed that the crop type, genotype and fertilizer type are the main factors affecting the grain yield, root system, genetic diversity and abundance of microorganisms. Thus, the combined use of less reactive P sources, which could be more soluble over time by the physicochemical processes and soil microbiota activity, together with more efficient genotypes might reduce the amount of soluble phosphate fertilizers applied annually to crops.

Find out more information about the HPSC talks here.