Non-antibiotic selection systems for soybean somatic embryos: the lysine analog aminoethyl-cysteine as a selection agent

<p>Abstract</p> <p>Background</p> <p>In soybean somatic embryo transformation, the standard selection agent currently used is hygromycin. It may be preferable to avoid use of antibiotic resistance genes in foods. The objective of these experiments was to develop a selection system for producing transgenic soybean somatic embryos without the use of antibiotics such as hygromycin.</p> <p>Results</p> <p>When tested against different alternate selection agents our studies show that 0.16 μg/mL glufosinate, 40 mg/L isopropylamine-glyphosate, 0.5 mg/mL (S-(2 aminoethyl)-L-cysteine) (AEC) and the acetolactate synthase (ALS) inhibitors Exceed^®and Synchrony^®both at 150 μg/mL inhibited soybean somatic embryo growth. Even at the concentration of 2 mg/mL, lysine+threonine (LT) were poor selection agents. The use of AEC may be preferable since it is a natural compound. Unlike the plant enzyme, dihydrodipicolinate synthase (DHPS) from <it>E. coli </it>is not feed-back inhibited by physiological concentrations of lysine. The <it>dapA </it>gene which codes for <it>E. coli </it>DHPS was expressed in soybean somatic embryos under the control of the CaMV 35S promoter. Following introduction of the construct into embryogenic tissue of soybean, transgenic events were recovered by incubating the tissue in liquid medium containing AEC at a concentration of 5 mM. Only transgenic soybeans were able to grow at this concentration of AEC; no escapes were observed.</p> <p>Conclusion</p> <p>Genetically engineered soybeans expressing a lysine insensitive DHPS gene can be selected with the non-antibiotic selection agent AEC. We also report here the inhibitory effects of glufosinate, (isopropylamine-glyphosate) (Roundup^®), AEC and the ALS inhibitors Exceed^®and Synchrony^®against different tissues of soybean</p

Variação genética e ambiental e teores de beta‑conglicinina e glicinina em cultivares de soja brasileiras

The objective of this work was to determine genetic and environmental effects on beta‑conglycinin and glycinin content in Brazilian soybean cultivars. The concentrations of these protein fractions were analyzedby scanning densitometry after electrophoresis, in 90 Brazilian soybean cultivars sown in Ponta Grossa, PR, in 2001. The effects of the sowing location were determined in the cultivar MG/BR 46 (Conquista), sown in16 locations of Goiás and Minas Gerais states (Central Brazil), and in the cultivar IAS 5, sown in 12 locations of Paraná and São Paulo states (Southern Brazil), in 2002 soybean season. A significant variability forbeta‑conglycinin (7S) and glycinin (11S) protein fractions ratio was observed among the 90 Brazilian soybean cultivars. 'MS/BRS 169' (Bacuri) and 'BR‑8' (Pelotas) presented the highest and the lowest 11S/7S ratios(2.76 and 1.17, respectively). Beta‑conglycinin protein fractions presented more variability than glycinin protein fractions. Grouping test classified 7S proteins in seven groups, 11S proteins in four groups, and proteinfraction ratios (11S/7S) in nine groups. Significant effect of sowing locations was also observed on protein fractions contents. There is a good possibility of breeding for individual protein fractions, and their subunits, without affecting protein content.O objetivo deste trabalho foi avaliar os efeitos da variação genética e ambiental sobre os teores de beta‑conglicinina e glicinina em cultivares de soja brasileiras. A concentração dessas frações protéicas foideterminada por densitometria após eletroforese, em 90 cultivares de soja, semeadas em Ponta Grossa, PR, em 2001. Os efeitos dos locais de semeadura foram determinados na cultivar MG/BR 46 (Conquista), semeada em 16 locais de Goiás e Minas Gerais, e na cultivar IAS 5, semeada em 12 locais no Paraná e em São Paulo, em 2002. Foi observada variabilidade significativa quanto à razão entre as frações protéicas da beta‑conglicinina (7S) e da glicinina (11S), entre as 90 cultivares avaliadas, em que a 'MG/BR 169' (Bacuri) apresentou amaior razão 11S/7S (2,76) e a 'BR‑8' (Pelotas) a menor (1,17). As frações protéicas de beta‑conglicinina apresentaram maior varibilidade do que as de glicinina. A análise de agrupamento discriminou as proteínas 7S em sete grupos, as 11S em quatro, e as razões 11S/7S em nove. Efeito significativo dos locais de semeadura também foi observado sobre os teores das frações protéicas. Existe uma boa possibilidade de melhoramento para as frações individuais de proteínas e suas subunidades, sem que o teor de proteína seja alterado

Genetic variation and environmental effects on beta-conglycinin and glycinin content in Brazilian soybean cultivars

The objective of this work was to determine genetic and environmental effects on beta-conglycinin and glycinin content in Brazilian soybean cultivars. The concentrations of these protein fractions were analyzed by scanning densitometry after electrophoresis, in 90 Brazilian soybean cultivars sown in Ponta Grossa, PR, in 2001. The effects of the sowing location were determined in the cultivar MG/BR 46 (Conquista), sown in 16 locations of Goiás and Minas Gerais states (Central Brazil), and in the cultivar IAS 5, sown in 12 locations of Paraná and São Paulo states (Southern Brazil), in 2002 soybean season. A significant variability for beta-conglycinin (7S) and glycinin (11S) protein fractions ratio was observed among the 90 Brazilian soybean cultivars. 'MS/BRS 169' (Bacuri) and 'BR-8' (Pelotas) presented the highest and the lowest 11S/7S ratios (2.76 and 1.17, respectively). Beta-conglycinin protein fractions presented more variability than glycinin protein fractions. Grouping test classified 7S proteins in seven groups, 11S proteins in four groups, and protein fraction ratios (11S/7S) in nine groups. Significant effect of sowing locations was also observed on protein fractions contents. There is a good possibility of breeding for individual protein fractions, and their subunits, without affecting protein content