Giovani Greigh de Brito

Expression of an osmotin-like protein from Solanum nigrum confers drought tolerance in transgenic soybean

BackgroundDrought is by far the most important environmental factor contributing to yield losses in crops, including soybeans [Glycine max (L.) Merr.]. To address this problem, a gene that encodes an osmotin-like protein isolated from Solanum nigrum var. americanum (SnOLP) driven by the UBQ3 promoter from Arabidopsis thaliana was transferred into the soybean genome by particle bombardment.ResultsTwo independently transformed soybean lines expressing SnOLP were produced. Segregation analyses indicated single-locus insertions for both lines. qPCR analysis suggested a single insertion of SnOLP in the genomes of both transgenic lines, but one copy of the hpt gene was inserted in the first line and two in the second line. Transgenic plants exhibited no remarkable phenotypic alterations in the seven analyzed generations. When subjected to water deficit, transgenic plants performed better than the control ones. Leaf physiological measurements revealed that transgenic soybean plants maintained higher leaf water potential at predawn, higher net CO2 assimilation rate, higher stomatal conductance and higher transpiration rate than non-transgenic plants. Grain production and 100-grain weight were affected by water supply. Decrease in grain productivity and 100-grain weight were observed for both transgenic and non-transgenic plants under water deficit; however, it was more pronounced for non-transgenic plants. Moreover, transgenic lines showed significantly higher 100-grain weight than non-transgenic plants under water shortage.ConclusionsThis is the first report showing that expression of SnOLP in transgenic soybeans improved physiological responses and yield components of plants when subjected to water deficit, highlighting the potential of this gene for biotechnological applications.

1-Methylcyclopropene and Aminoethoxyvinylglycine effects on yield components of field-grown cotton

A ocorrencia de estresses bioticos e abioticos pode alterar o balanco hormonal e desencadear a ativacao de vias envolvidas nas respostas do algodoeiro a estresses, resultando na abscisao de botoes, flores e macas em desenvolvimento e em menor rendimento de algodao em caroco e de fibras. Como parte desses mecanismos que primariamente regulam as respostas protetivas da planta contra estresses, o etileno e considerado um hormonio chave, envolvido nessas respostas e aumentos em seu nivel de sintese tem sido verificados em plantas submetidas a quaisquer tipos de estresse. Assim, o desenvolvimento de estrategias objetivando mitigar os seus efeitos negativos poderia reduzir a taxa de queda de estruturas reprodutivas e impactar positivamente na produtividade de fibras. Com esse proposito, 1-methylcyclopropeno (1-MCP), um composto inibidor da acao do etileno e aminoethoxyvinylglycina (AVG), um inibidor da sua sintese foram aplicados sobre o algodoeiro para investigar seus efeitos sobre o rendimento de algodao em caroco, de fibras, a percentagem de fibras e o stand final de plantas durante duas estacoes de crescimento (2010 e 2011). Assim, experimentos a campo em delineamento blocos casualizados completo com cinco repeticoes foram conduzidos. Os resultados obtidos evidenciam que os inibidores da sintese e da acao de etileno aumentaram o rendimento de algodao em caroco e de fibras em ambas as estacoes de crescimento. Os resultados obtidos pelo uso do AVG aplicado na fase reprodutiva inicial (primeiro botao floral) evidenciaram os maiores valores para os componentes de rendimento analisados, sendo os primeiros resultados obtidos no Brasil com tal proposito.

Carbon isotope fractionation for cotton genotype selection

The objective of this work was to evaluate the carbon isotope fractionation as a phenomic facility for cotton selection in contrasting environments and to assess its relationship with yield components. The experiments were carried out in a randomized block design, with four replicates, in the municipalities of Santa Helena de Goias (SHGO) and Montividiu (MONT), in the state of Goias, Brazil. The analysis of carbon isotope discrimination (Δ) was performed in 15 breeding lines and three cultivars. Subsequently, the root growth kinetic and root system architecture from the selected genotypes were determined. In both locations, Δ analyses were suitable to discriminate cotton genotypes. There was a positive correlation between Δ and seed‑cotton yield in SHGO, where water deficit was more severe. In this site, the negative correlations found between Δ and fiber percentage indicate an integrative effect of gas exchange on Δ and its association with yield components. As for root robustness and growth kinetic, the GO 05 809 genotype performance contributes to sustain the highest values of Δ found in MONT, where edaphoclimatic conditions were more suitable for cotton. The use of Δ analysis as a phenomic facility can help to select cotton genotypes, in order to obtain plants with higher efficiency for gas exchange and water use.