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

Characteristics of Nitrate Uptake From Nutrient Solution and Root Nitrate Reductase Activity Among Corn (Zea Mays L.) Genotypes

171 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1977.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD

Isolation and characterization of gsv mutants of grain pea (Pisum sativum) having white stem and green leaflets

Two Gsv<SUP>−</SUP> mutants have been isolated in mutagenized grain pea (Pisum sativum). A nuclear gene is affected in each mutant. The Gsv<SUP>−</SUP> plants are recessive homozygotes (gsv/gsv). They bear white stems and green leaves; the petiole, rachis, and veins on stipules and leaflets are also white. In the Gsv<SUP>−</SUP> plants, the stem is devoid of chlorophylls, although normal amounts of chlorophylla andb are present in leaflets. Mature chloroplasts and CO<SUB>2</SUB> reduction ability are present in mesophyll tissue of leaves but absent in stem. The characteristics of Gsv<SUP>−</SUP> mutants allow the conclusion that the genes involved in chloroplast development and photosynthetic functions are regulated by different nuclear genes in mesophyll leaf cells on the one hand and green cells of stem and related tissues in functionally different segments of shoot on the other. It is proposed that segment-wise genetic control of photosynthesis in shoot is a rule among higher plants