Cloning and Function Analysis of ω-3-Fatty Acid Desaturase 8 Gene from Perilla frutescens / 中国生物化学与分子生物学报

ω-3-Fatty acid desaturase 8 (FAD8), as a dehydrogenase enzyme, plays a key role in the transformation of saturated fatty acids into unsaturated fatty acids, which is helpful to enhance the freezing tolerance of plants. However, it remains unclear whether the expression level of FAD8 in Perilla frutescens is regulated by low temperature. Based on transcriptome data, the FAD8 gene was cloned, characterized and then successfully expressed in tobacco Nicotiana tabacum. The gene was designated as PfFAD8 and has a full-length coding sequence of 1 317 bp coding for 438 amino acids with a predicted molecular weight of 50 kD and a theoretical isoelectric point of 9. 13. Our research indicated that the expression of PfFAD8 in Perilla frutescens was increased under the freezing stress. To further confirm this result, a 35S::PfFAD8 vector were constructed and transformed into N. tabacum by Agrobacterium tumefaciens-mediated transformation. Transgenic tobacco leaves that over-expressed the PfFAD8 gene exhibited significantly higher unsaturated fatty acids (UFA) such as linoleic (C18:2) and palmitic acid (C16:0) content and advanced freezing tolerance. Moreover, PfFAD8 overexpression in transgenic tobacco leaves increases malondialdehyde (MDA) and proline (PRO) content, and enhances defense enzymes activities of superoxide dismutase (SOD) and catalase (CAT) to some extent under the cold condition, which might prevent the decline of UFA. Taken together, PfFAD8 overexpression in Perilla frutescens might be involved in the desaturation process of lipids leading to increased membrane stability and/ or induction of other genes related to freezing tolerance by octadecanoid pathway or lipid peroxidation products. Thus, PfFAD8 overexpression could be useful in the production of freeze-tolerant varieties of N. tabacum.

Transcriptome responses to heat- and cold-stress in ladybirds (Cryptolaemus montrouzieri Mulasnt) analyzed by deep-sequencing

BACKGROUND: Changed temperature not only threaten agricultural production, but they also affect individual biological behavior, population and community of many insects, and consequently reduce the stability of our ecosystem. Insect's ability to respond to temperature stress evolved through a complex adaptive process, thus resulting in varied temperature tolerance among different insects. Both high and low extreme temperatures are detrimental to insect development since they constitute an important abiotic stress capable of inducing abnormal biological responses. Many studies on heat or cold tolerance of ladybirds have focused on measurements of physiological and biochemical indexes such as supercooling point, higher/lower lethal temperatures, survival rate, dry body weight, water content, and developmental duration. And studies of the molecular mechanisms of ladybird responses to heat or cold stress have focused on single genes, such as those encoding heat shock proteins, but has not been analyzed by transcriptome profiling. RESULTS: In this study, we report the use of Digital Gene Expression (DGE) tag profiling to gain insight into transcriptional events associated with heat- and cold-stress in C. montrouzieri. About 6 million tags (49 bp in length) were sequenced in a heat stress group, a cold stress group and a negative control group. We obtained 687 and 573 genes that showed significantly altered expression levels following heat and cold shock treatments, respectively. Analysis of the global gene expression pattern suggested that 42 enzyme-encoding genes mapped to many Gene Ontology terms are associated with insect's response to heat- and cold-stress. CONCLUSIONS: These results provide a global assessment of genes and molecular mechanisms involved in heat and cold tolerance.

Resistência de espécies arbóreas submetidas a extremos climáticos de geada em diferentes sistemas agroflorestais / Resistance of arboreal species submitted to extreme frost in different agroforestry systems

O presente trabalho teve como objetivo avaliar a resposta das espécies arbóreas Schizolobium parahyba (Vell.) Blake (guapuruvu), Mimosa scabrella Benth. (bracatinga), Peltophorum dubium (Spr.) Taubert (canafístula), Parapiptadenia rigida (Benth.) Brenan (angico-vermelho) e o híbrido Eucalyptus urophylla S.T. Blake x Eucalyptus grandis Hill ex Maiden (eucalipto) em consórcio com a cana-de-açúcar (Saccharum spp.) em dois arranjos de sistemas agroflorestais (faixa - 3x3m + 12m e linha - 6x1,5m) submetidos a extremos climáticos de geada, na região Noroeste do Rio Grande do Sul. Os danos (resistência á geada) foram avaliados segundo o sistema de notas utilizado por HIGA et al. (2000) no qual atribuiu-se uma nota de 0 a 10 conforme a intensidade do dano na planta. Para os graus de resistência à geada, adaptou-se metodologia utilizada por CARVALHO (1981), a qual também é em função da intensidade do dano na planta. Diante da condição de geada estudada, observa-se que os diferentes arranjos de sistemas agroflorestais afetam a resistência da espécie guapuruvu, sendo sensível no sistema agroflorestal faixa e moderadamente tolerante no sistema linha. Em ambos os sistemas, as espécies angico-vermelho, bracatinga e eucalipto mostram-se resistentes, enquanto que a canafístula demonstra ser tolerante.

The present research had the aim to evaluate the answers of the arboreal species Schizolobium parahyba (Vell.) Blake (guapuruvu), Mimosa scabrella Benth. (bracatinga), Peltophorum dubium (Spr.) Taubert (canafístula), Parapiptadenia rigida (Benth.) Brenan (angico-vermelho) and the hybrid Eucalyptus urophylla S.T. Blake x Eucalyptus grandis Hill ex Maiden (eucalipto) in consortium with sugar cane (Saccharum spp.) in two agroforestry arrangement systems (strip - 3x3m + 12m and line - 6x1,5m) submitted to climatic extreme frost conditions, in the Northwest of Rio Grande do Sul. The damages (resistance to frost) were appraised according to the system of notes used by HIGA et al. (2000) in which a note from 0 to 10 was attributed according to the intensity of the damage to the plant. For the resistance degrees to frost, it was adapted the methodology used by CARVALHO (1981), which is also in function of the intensity of the damage to the plant. Upon the frost condition studied, it was observed that the results demonstrated that different of agroforest system arrangements damaged the resistance of the guapuruvu specie, being sensitive in the agroforest system strip and moderatelly tolerant in the system line. In both systems, the species angico-vermelho, bracatinga e eucalipto showed resistance, while the canafístula demonstrated to be tolerant.

Tolerância ao frio do amendoim forrageiro / Cold tolerance of forage peanut

A produtividade de uma pastagem perene tropical, em regiões de clima temperado, é dependente de seu comportamento em relação às condições de temperatura. A avaliação da sensibilidade das plantas, através da sua exposição a temperaturas inferiores a 2°C em ambiente controlado, pode ser um procedimento bastante eficiente na predição de resistência, em função de assegurar uma homogeneidade dos níveis de frio. Considerando-se à reduzida disponibilidade de trabalhos científicos relacionados com a avaliação de leguminosas forrageiras tropicais quanto à tolerância ao frio, este experimento teve como objetivo avaliar o comportamento do amendoim forrageiro (cv. "Amarillo") sob temperaturas inferiores a 2°C. O delineamento experimental adotado foi completamente casualizado com 15 repetições e dois tratamentos, com exposição (CE) e sem exposição ao frio (SE). Os caracteres mensurados foram: número de folhas por estolho, espessura do estolho e número de brotações novas. Os resultados indicaram que a exposição do amendoim forrageiro a um intervalo de temperatura de -1,0 a 1,3°C por um período de 3 horas é capaz de causar estresse de frio nas plantas, provocando uma redução no número de folhas e estimulando a formação de novas brotações, sem provocar a morte das plantas.

The yield of tropical perennial forages in temperate climate areas depends on its cold tolerance. The exposure of genotypes to temperatures below 2oC, under controlled conditions is an efficient methodology to predict cold tolerance, since it maintains homogeneous levels of cold. Due to absence of information related to cold tolerance of tropical forages, this experiment was developed aiming to evaluate the behavior of forage peanut exposed to temperatures below 2oC. The design adopted was completely randomized with 15 replications and two treatments: exposed and not exposed to cold. The traits measured were: number of leaves per stolon; thickness of stolon and number of new shoots. The results showed that the exposition of the forage peanut to a range of temperature from -1.0 to 1.3 °C, for 3 hours, causes cold stress in the plants, resulting in a reduction of the number of leaves per solon and stimulating the emergency of new shoots, but did not kill the plants.

Comparison of the vascular reaction to cold of the finger among groups of swimmers, track and field athletes, gymnasts and non-athletes / 体力科学

The difference in vascular reaction to cold among 5 groups of 17 swimmers with experience of 3 years or longer, 13 swimmers with experience of 2 years or less, 12 track and field athletes, 7 gymnasts and 9 non-athletes were studied. Four components which are useful indexes of cold tolerance showed statistically significant differences among 5 groups. From test results of linear comparison between each group, it was determined that athletes compared with non-athletes, and swimmers with other athletes possess better cold tolerance. But there was no significant difference between swimmers with different types in swimming experience years or between outdoor-and indoor-athletes.