ABSTRACT
Polyploid plants can exhibit transcriptional modulation in homeologous genes in response to abiotic stresses. Coffea arabica, an allotetraploid, accounts for 75% of the world's coffee production. Extreme temperatures, salinity and drought limit crop productivity, which includes coffee plants. Mannitol is known to be involved in abiotic stress tolerance in higher plants. This study aimed to investigate the transcriptional responses of genes involved in mannitol biosynthesis and catabolism in C. arabica leaves under water deficit, salt stress and high temperature. Mannitol concentration was significantly increased in leaves of plants under drought and salinity, but reduced by heat stress. Fructose content followed the level of mannitol only in heat-stressed plants, suggesting the partitioning of the former into other metabolites during drought and salt stress conditions. Transcripts of the key enzymes involved in mannitol biosynthesis, CaM6PR, CaPMI and CaMTD, were modulated in distinct ways depending on the abiotic stress. Our data suggest that changes in mannitol accumulation during drought and salt stress in leaves of C. arabica are due, at least in part, to the increased expression of the key genes involved in mannitol biosynthesis. In addition, the homeologs of the Coffea canephora subgenome did not present the same pattern of overall transcriptional response, indicating differential regulation of these genes by the same stimulus. In this way, this study adds new information on the differential expression of C. arabica homeologous genes under adverse environmental conditions showing that abiotic stresses can influence the homeologous gene regulation pattern, in this case, mainly on those involved in mannitol pathway.
Subject(s)
Coffea/genetics , Mannitol/metabolism , Biosynthetic Pathways/genetics , Coffea/metabolism , Dehydration/metabolism , Fructose/metabolism , Gene Expression Regulation, Plant , Genes, Plant , Heat-Shock Response , Phylogeny , Plant Proteins/genetics , Plant Proteins/metabolism , Salt Tolerance , Transcription, GeneticABSTRACT
The success of sericiculture greatly depends on the availability of mulberry cultivars with agronomic characteristics that maximize the production and quality of silkworm, Bombyx mori L., cocoons. The effect of the cultivars Miura (standard) and Korin, and the hybrids SM 14, SM 63, SK 1, SK 4 and FM 86 was evaluated on silkworm development, and on cocoon production and quality, at the Instituto Agronômico do Paraná, IAPAR, in Londrina, PR, Brazil (23 +/- 3 degrees C; 61 +/- 8% RH). The experiment was arranged in a randomized block design with four replicates. Larvae feeding either on 'SK 4' or on 'Korin' showed a higher weight compared to that of larvae feeding on 'Miura'. Cocoon weight (both sexes) and pupae weight (male) obtained with larvae fed on SK 4 were higher compared with that of insects that fed on Miura; there was no difference among the remaining treatments. Silk net weight was independent of the cultivar used. Cocoon shell weight was similar amongst insects raised on 'Miura' and on the other mulberry materials. The percentage of cocoon spinning was higher than 90% in all treatments, with the spinning concentrating in the first two days. The proportion of first grade cocoons varied from 80% (SK4) to 90%. The results obtained with the studied cultivars were either similar or superior to that of the standard cultivar Miura with emphasis to 'SK 4', thus showing the potential use of these cultivars in sericulture in the state of Paraná.
Subject(s)
Bombyx/growth & development , Morus/classification , AnimalsABSTRACT
O êxito da sericicultura depende em grande parte da disponibilidade de cultivares de amoreira com características agronômicas que maximizem a produção e a qualidade dos casulos do bicho-da-seda, Bombyx mori L. Os efeitos das cultivares Miura (padrão) e Korin, e dos híbridos SM 14, SM 63, SK 1, SK 4 e FM 86 sobre o desenvolvimento, produção e qualidade do casulo do bicho-da-seda foram avaliados no Instituto Agronômico de Paraná, IAPAR, Londrina, PR (23 ± 3°C; 61 ± 8 por cento RH). Utilizou-se delineamento experimental de blocos ao acaso com quatro repetições. Lagartas alimentadas com folhas do híbrido SK 4 ou da cultivar Korin tiveram aumento significativo de peso em comparação com as alimentadas com folhas da cultivar padrão. O peso de casulos (ambos os sexos) e o peso de pupa (macho), obtidos com insetos criados com SK 4, foram superiores aos de insetos criados com a cultivar Miura; não houve diferença entre os demais tratamentos. O teor de seda líquida não foi influenciado pelas cultivares testadas. O peso de casca sérica obtido com lagartas alimentadas com Miura foi similar ao de lagartas alimentadas com os demais materiais. O encasulamento concentrou-se nos dois primeiros dias e foi superior a 90 por cento em todos os tratamentos. A porcentagem de casulos de primeira variou de 80 por cento (SK 4) a 90 por cento. Em geral, os resultados obtidos com as cultivares estudadas foram semelhantes ou superiores ao padrão Miura, com ênfase para o híbrido SK 4, demonstrando o potencial de uso dessas cultivares na sericicultura paranaense.
The success of sericiculture greatly depends on the availability of mulberry cultivars with agronomic characteristics that maximize the production and quality of silkworm, Bombyx mori L., cocoons. The effect of the cultivars Miura (standard) and Korin, and the hybrids SM 14, SM 63, SK 1, SK 4 and FM 86 was evaluated on silkworm development, and on cocoon production and quality, at the Instituto Agronômico do Paraná, IAPAR, in Londrina, PR, Brazil (23 ± 3°C; 61 ± 8 percent RH). The experiment was arranged in a randomized block design with four replicates. Larvae feeding either on SK 4 or on Korin showed a higher weight compared to that of larvae feeding on Miura". Cocoon weight (both sexes) and pupae weight (male) obtained with larvae fed on SK 4 were higher compared with that of insects that fed on Miura; there was no difference among the remaining treatments. Silk net weight was independent of the cultivar used. Cocoon shell weight was similar amongst insects raised on Miura and on the other mulberry materials. The percentage of cocoon spinning was higher than 90 percent in all treatments, with the spinning concentrating in the first two days. The proportion of first grade cocoons varied from 80 percent (SK4) to 90 percent. The results obtained with the studied cultivars were either similar or superior to that of the standard cultivar Miura with emphasis to SK 4, thus showing the potential use of these cultivars in sericulture in the state of Paraná.
