Biology subjects

Otegui, M. E.

Publications and source records attributed to Otegui, M. E..

7 recordsLinked to original sources

bioRxiv2026

Isogenic reciprocal grafts with transgenic HaHB11 plants dissect shoot and root contributions to yield in field-grown soybean: a multi-omic study

Soybean must coordinate root and shoot signals to optimize yield. Grafting is a powerful tool to study this communication. However, most studies compare contrasting genotypes and cannot separate genotype from graft combination effects. Here we used isogenic soybean lines to dissect root and shoot contributions in the field. These lines differ from controls in a single gene, either HaHB11 or HaHB4, two sunflower HD-Zip I transcription factors associated with increased grain number. Unexpectedly, heterografted plants outperformed homografts in several yield-related traits, an effect not previously documented in soybean. This advantage was reproduced with both HaHB11 and HaHB4 scions, suggesting the effect is not gene-specific. Under non-stress conditions the scion governed yield-related traits, particularly pod number, as well as the leaf transcriptome, whereas both organs left subtle metabolic signatures. The root contribution was minor and confined to the R6-R7 transition, where it was specific to HaHB11. The highest-yielding combination was a control rootstock with an HaHB11 scion (CH11), which increased grain number by [~]30% over the best homograft. CH11 showed higher stomatal conductance and lower leaf temperature; yet CH11 and HaHB11 homografts were remarkably similar, sharing higher stomatal density, differing in only four leaf-expressed genes, and lacking a metabolomic signature. Thus, under non-stress conditions, soybean grain number is governed by the scion and the graft combination, and accompanied by early physiological differences rather than by leaf molecular reprogramming.

plant biology↗

bioRxiv2024

Introgression of the sunflower HaHB4 gene in modern wheat: An advancement in resilience to deal with climate change

Breeding for improved tolerance to water deficit is critical to mitigate climate change impact on wheat yield. In 2020, Argentina approved the first wheat transformed with the sunflower HaHB4 gene (INDOO412-7), which increased yield by 16% compared to the non-transformed parental Cadenza under drought conditions. Previous studies may have overestimated HaHB4 benefits, as Cadenza is a long cycle for the Pampas region. Quantifying the yield advantage of HaHB4 in modern, well-adapted cultivars and elucidating the physiological processes involved, is crucial for identifying optimal environments for this technology. In a broad network of experiments (one greenhouse and 29 field environments), an HaHB4-introgressed line of Algarrobo was compared with the conventional cultivar. Under water deficit during the reproductive phase, the yield advantage of HaHB4 was 15% in the greenhouse and 13% in the field. HaHB4 improved the relative yield by 0.06 to 0.08 % per mm of water deficit. The enhanced water use and water use efficiency conferred by HaHB4, allowed maintaining growth and yield under water deficit. HaHB4 showed the highest benefit with moderate heat stress ({sum}Tmax > 30 {degrees}C [~]40-60 {degrees}Cd). In areas prone to drought combined with heat stress, HaHB4 would enhance yield stability by improving water-limited yield. HighlightsHaHB4-introgressed wheat enhanced water-limited yield by maintaining the crop growth under moderate to severe water deficit combined with mild heat stress through increasing water use and water use efficiency.

plant biology↗

bioRxiv2024

Field-tested HaHB11 and HaHB4 soybean exhibit increased grain number and heat tolerance at the reproductive stage

Soybean is one of the primary sources of vegetable oil and protein worldwide. However, its yield improvement has lagged behind the other major crops. This study explored the potential of the sunflower transcription factor HaHB11 to enhance soybean yield and heat stress tolerance. We generated transgenic soybean plants expressing HaHB11 and evaluated their performance across four field trials. The HaHB11 plants showed a significant increase in grain number per plant compared to controls, which can be related to an increased number of nodes and pods per plant. Flowering dynamics analysis revealed delayed blooming and an increased number of flowers per node, leading to a higher pod set, particularly between nodes four and six. Principal component analysis across field trials identified temperature as a crucial factor influencing grain number, enhancing the differences exhibited by HaHB11 plants. The pollen from transgenic plants germinated better, and tubes were longer than controls under heat stress. Carbohydrate distribution analyses indicated differential allocation of nutrients, supporting the increased pod and grain set in HaHB11 plants. Additionally, vegetation indices can distinguish HaHB11 plants from controls in several developmental stages. These results indicated that HaHB11 enhances soybean yield under heat stress, becoming a promising technology for soybean improvement. HighlightSoybean transformed with the sunflower gene HaHB11 was tested in the field for four campaigns, showing differential allocation of nutrients, increased number of nodes, pods, grains, and heat tolerance.

plant biology↗

bioRxiv2024

Kernel weight and source/sink ratio determination of temperate maize hybrids with different end uses under contrasting environments

Maize (Zea mays L.) production in Argentina changed markedly during the last decade due to the widespread adoption of late sowings, expanding its productive area, and diversifying crop end-uses. This study evaluated environment (two years x two sowing dates) and management practices (two nitrogen levels) effects on kernel weight, its physiological determinants, source/sink ratios, and water-soluble carbohydrates in stem (WSCS) of eight temperate maize hybrids bred for different uses (3 graniferous, 2 dual-purpose, 2 silage). Crop growth simulations allowed the estimation of percent variation in WSCS remobilization (null, partial, or total) for different production systems (18 scenarios) and climate conditions (41 growing seasons). Nitrogen fertilization increased kernel weight in early sowings, with minimal effects in late sowings. WSCS remobilization during kernel filling was higher in late than in early sowings, with no differences among hybrid types. Regarding hybrid types, dual-purpose and silage hybrids showed the highest and the lowest kernel weight respectively, and graniferous hybrids had the highest source/sink ratio during the effective kernel-filling period. Simulations underscored the importance of sowing date and nitrogen supply on WSCS for irrigated and dryland maize farming systems in a temperate environment, with important implications for grain and silage production at the farm level.

plant biology↗

bioRxiv2023

CRONOSOJA: a daily time-step hierarchical model predicting soybean development across maturity groups in the Southern Cone

Accurate prediction of phenology is the most critical aspect for the development of models aimed at estimating seed yield, particularly in species that exhibit variable sensitivity to environmental factors throughout the cycle and among genotypes. With this purpose, we evaluated the phenology of 34 soybean varieties in 43 field experiments located in Argentina, Uruguay, and Paraguay. Experiments covered a broad range of maturity groups (2.2-6.8), sowing dates (from spring to summer), and latitude range (24.9-35.6 {degrees}S), thus ensuring a wide range of thermo-photoperiodic conditions during the growing season. Based on the observed data, daily time-step models were developed and tested, first for each genotype, and then across maturity groups. We identified base temperatures specific for different developmental stages and an extra parameter for calculating the photoperiod effect after the R1 stage (flowering). Also, an optimum photoperiod length for each maturity group was found. Model selection showed that the determinants of phenology across maturity groups were mainly affecting the duration of vegetative and early reproductive stages. Even so, early phases of development were better predicted than later ones, particularly in locations with cool growing seasons, where the model tended to overestimate their duration. Overall, we developed a soybean phenology model that, owing to its process-based nature, is able to simulate phenology well across widespread locations and sowing dates yet, because of its simplicity, can be adopted by a wide audience. The final model was made available at http://cronosoja.agro.uba.ar.

plant biology↗

bioRxiv2021

HaHB11 transformed maize has improved yield under waterlogging and defoliation in control and field conditions

HaHB11 is a sunflower transcription factor previously described as conferring improved yield to maize hybrids and lines. Here we report that transgenic HaHB11 maize lines exhibited a better performance funder waterlogging, both in greenhouse and field trials carried out during three growth cycles. One of these trials was particularly affected by a strong storm during flowering, causing severe defoliation. Controlled defoliation assays indicated that the transgenic genotypes were able to set more grains than controls. Hybrids were generated by crossing B73 HaHB11 lines with the contrasting Mo17 lines and tested in the field. These hybrids exhibited the same beneficial traits as the parental lines when compared with their respective controls. Waterlogging tolerance coursed via the root architecture improvement, including more xylem vessels, reduced tissue damage, less superoxide accumulation, and altered carbohydrate metabolism compared to controls. Multivariate analyses corroborated the robustness of the differential traits observed. Furthermore, canopy spectral reflectance data, computing 29 vegetation indices associated with biomass, chlorophyll, and abiotic stress, helped to identify genotypes as well as their growing conditions. Altogether the results reported here indicate that this sunflower gene constitutes a suitable tool to improve maize plants for environments prone to waterlogging and/or wind defoliation. One sentence summaryPhenotyping and big data analyses indicate that the transcription factor HaHB11 confers waterlogging and defoliation tolerance, and increased yield to maize lines and hybrids in all tested conditions.

plant biology↗

bioRxiv2019

Successful field performance in dry-warm environments of soybean expressing the sunflower transcription factor HaHB4

Soybean yield is limited primarily by abiotic constraints. No transgenic soybean with improved abiotic-stress tolerance is available in the market. We transformed soybean plants with genetic constructs able to express the sunflower transcription factor HaHB4, which confers drought tolerance to Arabidopsis and wheat plants. One line (b10H) carrying the sunflower promoter was chosen among three independent lines because it exhibited the best performance in seed yield (SY). Such line was evaluated in the greenhouse and in twenty-seven field trials developed in different environments of Argentina. In greenhouse experiments, transgenic plants showed increased SY under stress conditions together with wider epycotyl diameter, enlarged xylem area and enhanced water use efficiency than controls. They also exhibited enhanced SY in warm-dry field conditions. This response was accompanied by the increased in seed number that was not compensated by the decreased in individual seed weight. The transcriptome analysis of plants from a field trial with maximum SY difference between genotypes indicated an induction of genes encoding redox and heat shock proteins in b10H. Collectively, our results indicate that soybeans transformed with HaHB4 are expected to have reduced SY penalization when cropped in warm-dry conditions, which constitute the best target environments for this technology. HighlightSoybean transformed with the sunflower gene encoding the transcription factor HaHB4 was evaluated in greenhouse and field trials. Transgenic plants significantly outyielded controls in drought-warm environments due to, at least in part, increased seed number, xylem area, and water use efficiency as well as to the induction of genes encoding redox and heat shock proteins.

plant biology↗