Influence of antibiotics on indirect organogenesis of Teak

Agrobacterium is the largest method employed to transform woody plants. The bacterium is required to introduce the transgene into the plant nuclear genome. After transferring T-DNA to the plant cell, the bacteria affect plant growth negatively and have to be eliminated from plant tissue culture medium through the use of antibiotics. The effect of different antibiotics (timentin, cefotaxime and carbenicillin) on in vitro shoot regeneration of teak (Tectona grandis L. f.) was compared in hypocotyl, mature cotyledon and cotyledonary segments explants. Timentin and cefotaxime (100-300 mg l-1) did not affect shoot regeneration and the number of shoots per explant. Moreover, at these concentrations, the two antibiotics seem to stimulate shoot regeneration. Carbenicillin at a dosage of 300 mg l-1 as well as cefotaxime and timentin at a dosage of 500 mg l-1 induced abundant calli formation and inhibited regeneration. Our data show that cefotaxime and timentin (300 mg l-1) can be harmless to teak regeneration and can be used as bactericide agents during Agrobacterium-mediated transformation of Tectona grandis. Furthermore, we discuss the effect of antibiotic degradation on plant morphogenesis and its effect on regeneration from different explants

Loss of type-IV glandular trichomes is a heterochronic trait in tomato and can be reverted by promoting juvenility

Glandular trichomes are structures with widespread distribution and deep ecological significance. In the Solanum genus, type-IV glandular trichomes provide resistance to insect pests. The occurrence of these structures is, however, poorly described and controversial in cultivated tomato (Solanum lycopersicum). Optical and scanning electron microscopy were used to screen a series of well-known commercial tomato cultivars, revealing the presence of type-IV trichomes on embryonic (cotyledons) and juvenile leaves. A tomato line overexpressing the microRNA miR156, known to promote heterochronic development, and mutants affecting KNOX and CLAVATA3 genes possessed type-IV trichomes in adult leaves. A re-analysis of the Woolly (Wo) mutant, previously described as enhancing glandular trichome density, showed that this effect only occurs at the juvenile phase of vegetative development. Our results suggest the existence of at least two levels of regulation of multicellular trichome formation in tomato: one enhancing different types of trichomes, such as that controlled by the WOOLLY gene, and another dependent on developmental stage, which is fundamental for type-IV trichome formation. Their combined manipulation could represent an avenue for biotechnological engineering of trichome development in plants

Desempenho ponderal de novilhas mestiças Holandês × Zebu submetidas a duas estratégias de suplementação mineral Ponderal performance of crossbred Holstein × Zebu heifers submitted to two mineral supplementations strategies

Avaliou-se o desempenho ponderal de novilhas em regime de pastejo rotacionado consumindo dois tipos de suplemento mineral. Utilizaram-se 25 novilhas Holandês &times; Zebu, 9 como animais reguladores e 16 como animais-prova, divididas em quatro tratamentos: capim-mombaça e sal seletivo (MSS); capim-mombaça e sal comercial (MSC); capim-elefante e sal seletivo (ESS); e capim-elefante e sal comercial (ESC). O ganho médio diário (GMD) foi calculado pesando-se os animais-prova a cada 28 dias após jejum alimentar de 16 horas. Foram avaliados os consumos de matéria seca de lâmina foliar verde (CMSLFV) e a digestibilidade aparente da matéria seca de lâmina foliar verde (DMSLFV) utilizando-se óxido crômico como marcador externo e fibra em detergente neutro indigerível como marcador interno. Foram mensurados os consumos dos suplementos minerais e avaliados os teores de matéria seca, proteína bruta, fibra em detergente neutro e de Ca, P, K, Mg, Na, Cu, Zn, Fe e Mn somente em amostras de lâmina foliar. O delineamento estatístico utilizado foi o inteiramente casualizado em esquema fatorial 2 &times; 2 (gramínea e mistura mineral). Cada tratamento foi composto por quatro animais, de modo que cada animal constituiu uma unidade experimental. Apenas os minerais Cu, Na e Zn foram encontrados em quantidades insuficientes nas forrageiras. Os CMSLFV não foram influenciados por nenhuma das variáveis estudadas nem por suas interações. Houve interação sal mineral &times; gramínea para a DMSLFV. O GMD foi influenciado apenas pelas gramíneas; o desempenho dos animais que consumiram o capim-elefante foi superior. A composição nutricional do capim-elefante foi ligeiramente superior à do capim-mombaça, o que provavelmente proporcionou melhor desempenho aos animais deste tratamento.<br>The ponderal performance of heifers under rotational grazing fed two types mineral supplement was evaluated. A total of 25 heifers Holstein &times; Zebu, including nine regulator animals and 16 test animals, was divided into four treatments: mombaçagrass (Panicum maximum, CV. Mombaça) with selective salt (MSS), mombaçagrass with commercial salt (MSC), elephantgrass (Pennisetum purpureum, CV. Napier) with selective salt (ESS) and elephantgrass with commercial salt (ESC). Average daily live weight gain (DWG) was calculated by weighing the test animal every 28 days after fasting of 16 hours. Dry matter intake (CMSLFV) and apparent digestibility (DMSLFV) of green leaf blade were evaluated with chromium oxide and indigestible neutral detergent fiber, as external and internal markers, respectively. Mineral supplement intake was measured and the levels of dry matter, crude protein, and of Ca. P, K, Mg, Na, Cu, Zn, Fe and Mn only in grass leaves samples. A completely randomized design in 2 &times; 2 factorial arrangement (grass and mineral mix), was used. Each treatment was composed by four animals, and each animal as considered a experimental unit. Only Cu, Na and Zn were deficient in the forages. The CMSLFV were not affected by the studied variables and no significant interactions were observed. There was interaction between salt mix and grass for DMSLF. The DWG was affected only by grasses, the performance that ingested elephantgrass was higher. The nutritional composition of the elephantgrass was slightly better than that of mombaçagrass what probably provided better weight gains for the animals in this treatment

Building the sugarcane genome for biotechnology and identifying evolutionary trends

Sugarcane is the source of sugar in all tropical and subtropical countries and is becoming increasingly important for bio-based fuels. However, its large (10 Gb), polyploid, complex genome has hindered genome based breeding efforts. Here we release the largest and most diverse set of sugarcane genome sequences to date, as part of an on-going initiative to provide a sugarcane genomic information resource, with the ultimate goal of producing a gold standard genome151CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP2009/51632-1; 2009/09217-7; 2008/58243-8; 2009/09116-6; 2011/05317-7; 2008/54201-9sem informação2008/52074-0; 2010/05591-9; 2008/58031-0; 2008/52197-4; 08/52146-