Global interest in sugarcane has increased significantly in recent years due to its economic impact on sustainable energy production. Sugarcane breeding and better agronomic practices have contributed to a huge increase in sugarcane yield in the last 30 years. Additional increases in sugarcane yield are expected to result from the use of biotechnology tools in the near future. Genetically modified (GM) sugarcane that incorporates genes to increase resistance to biotic and abiotic stresses could play a major role in achieving this goal. However, to bring GM sugarcane to the market, it is necessary to follow a regulatory process that will evaluate the environmental and health impacts of this crop. The regulatory review process is usually accomplished through a comparison of the biology and composition of the GM cultivar and a non-GM counterpart. This review intends to provide information on non-GM sugarcane biology, genetics, breeding, agronomic management, processing, products and byproducts, as well as the current technologies used to develop GM sugarcane, with the aim of assisting regulators in the decision-making process regarding the commercial release of GM sugarcane cultivars.

Lysine-ketoglutarate reductase activity was detected and characterzed in the developing endosperm of maize (Zea mays L). The enzyme showed specificity for its substrates: lysine, a-ketoglutarate, and NADPH. Formation of the reaction product saccharopine was demonstrated. The pH optimum of the enzyme was cdose to 7, and the Km for lysine and aketoglutarate were 5.2 and 1.8 millmolar, respectively. between 25 and 70%o saturation was collected and taken up in 2.5 ml of extraction buffer. After desalting on a Sephadex G-25 column (1.5 x 16 cm), the protein fraction was assayed for lysineketoglutarate reductase activity using conditions based on those described by Hutzler and Dancis (7). The assay mixture contained K-phosphate (pH 7.0; 300 ,umol), L-lysine (50 ,pmol), a-ketoglutarate (25 ,umol), NADPH (300 nmol), and enzyme (0.1-0.2 mg protein) in a total volume of 3 ml. The mixture was incubated at 30°C, and oxidation of NADPH was monitored in a spectrophotometer at 340 nm.Lysine-ketoglutarate reductase catalyzes the following reaction: lysine + a-ketoglutarate + NADPH -* saccharopine + NADP+ The enzyme has been characterized in human and animal tissues (3,7,8) where it is believed to catalyze the first step of lysine catabolism (4). A similar reaction involving NAD is catalyzed by saccharopine dehydrogenase, an enzyme found in yeast and fungi where the reverse of the above reaction is considered to be the final step of lysine biosynthesis (5,6,12,16). Thus, in some organisms saccharopine is an intermediate of lysine biosynthesis while in the others it appears to be involved in lysine breakdown. Actually, several pathways for lysine catabolism are known (11), but in higher plants no general pathway has been established. Nevertheless, tracer studies with barley seedlings have provided strong evidence for the pathway involving saccharopine as intermediate (10), suggesting that this route may be important for lysine breakdown in cereals at least. However, we are unaware of any studies with enzymes in higher plants in support of this pathway.In this report, we describe the characterization of lysine-ketoglutarate reductase in developing maize endosperm, a tissue known to degrade lysine extensively (14). MATERIALS AND METHODS RESULTS AND DISCUSSIONThe data in Table I show that partially purified extracts of maize endosperm oxidized NADPH in the presence of lysine and a-ketoglutarate. In the absence of one or both of these substrates, the oxidation of NADPH was minimal. Specificity for the substrates is indicated by the fact that several amino acids, including closely related structures such as L-ornithine and D-lysine, would not substitute for L-lysine, nor would oxaloacetate or pyruvate substitute for a-ketoglutarate. NADH would not replace NADPH as electron donor, as was found for the enzyme from human liver (7).To confirm that the activity being measured was truly lysineketoglutarate reductase, it would be essential to demonstrate the formation of saccharopine in the assay. This was attempted using I4CJlysine...

A n open-cell photoacoustic (OCPA) spectroscopic technique is described which can assess genetically rooted differences in the response of live specimens of corn (Zea Mays L.) to the toxic action of aluminium. Specimens f r o m a susceptible and a tolerant inbred line were examined. The differences in their OCPA in vivo leaf spectra were evident and an interpretation is given based o n the genetically controlled response of the inbreds t o aluminium toxicity. A n earlier discrimination among specimens is obtained with this technique than has been possible so far w i t h previous techniques.

O efeito do fotoperíodo curto na morfologia e biologia reprodutiva dos teosintos, Zea mays ssp. mexicana (Schräder) Iltis (raças Central Plateau e Chalco Los Reyes), Z. mays ssp. parviglumis var. huehuetenanguensis (Iltis & Doebley), Z. luxuriam (Durieu & Ascherson) Bird e Z. diploperennis (Iltis, Doebley & Guzman) e do milho mazóide 1-8, Z. mays ssp. mays L., foi estudado na Área Experimental da UNICAMP (SP) 22º54' latitude sul, de fevereiro a julho de 1989. Os representantes da espécie Z. mays ssp. mexicana foram os mais precoces, seguidos do Z. mays ssp. mays, Z. diploperennis, Z. luxurians e Z. mays ssp. parviglumis var. huehuetenanguensis. Pela análise canónica, observou-se que esses acessos de germoplasma estão distribuídos em 4 diferentes grupos, onde as características: início e fim da antese na panícula terminal e início e fim da antese nas panículas dos ramos laterais foram as principais responsáveis pela discriminação das várias populações de teosinto e do milho. Z. mays ssp. parviglumis var. huehuetenanguensis foi colocada num grupo intermediário entre representantes da Seção Zea e da Seção Luxuriantes. Esses resultados corroboram dados recentes de outros pesquisadores baseados em análises isoenzimáticas, e discordam portanto da classificação de Doebley & Iltis (1980), baseada na morfologia das inflorescências masculinas e forma da cúpula que reveste o fruto.
The effect of short daylength on the morphology and reproduction of teosinte, Zea mays ssp. mexicana (Schräder) Iltis (races Central Plateau and Chalco Los Reyes), Z. mays ssp. parviglumis var. huehuetenanguensis (Iltis & Doebley), Z. luxurians (Durieu & Ascherson) Bird and Z. diploperennis (litis, Doebley & Guzman) were studied in comparison with a maize population at the experimental area of UNICAMP (SP), 22º54' S, on February-July 1989. Daily phenological observations showed that Z. mays ssp. mexicana populations were the earliest to flower followed by Z. mays ssp. mays, Z. diploperennis, Z. luxurians and Z. mays ssp. parviglumis var. huehuetenanguensis. According to a canonical analysis it was found that these germplasm accessions were distributed in four different groups according to the traits begining and ending of flowering of terminal panicles, and begining and ending of flowering of panicles of lateral branches. The population of Z. mays ssp. parviglumis var. huehuetenanguensis was placed as a intermediary group between Section Zea and Section Luxuriantes. These findings agree with recent works based on isoenzymatic analysis and disagree with the classification by Doebley & litis (1980) based on morphology of male inflorescence and shape of the cupule