Soybean is an important crop for Brazilian agribusiness. However, many factors can limit its production, especially root-knot nematode infection. Studies on the mechanisms employed by the resistant soybean genotypes to prevent infection by these nematodes are of great interest for breeders. For these reasons, the aim of this work is to characterize the transcriptome of soybean line PI 595099-Meloidogyne javanica interaction through expression analysis. Two cDNA libraries were obtained using a pool of RNA from PI 595099 uninfected and M. javanica (J2) infected roots, collected at 6, 12, 24, 48, 96, 144 and 192 h after inoculation. Around 800 ESTs (Expressed Sequence Tags) were sequenced and clustered into 195 clusters. In silico subtraction analysis identified eleven differentially expressed genes encoding putative proteins sharing amino acid sequence similarities by using BlastX: metallothionein, SLAH4 (SLAC1 Homologue 4), SLAH1 (SLAC1 Homologue 1), zinc-finger proteins, AN1-type proteins, auxin-repressed proteins, thioredoxin and nuclear transport factor 2 (NTF-2). Other genes were also found exclusively in nematode stressed soybean roots, such as NAC domain-containing proteins, MADS-box proteins, SOC1 (suppressor of overexpression of constans 1) proteins, thioredoxin-like protein 4-Coumarate-CoA ligase and the transcription factor (TF) MYBZ2. Among the genes identified in non-stressed roots only were Ser/Thr protein kinases, wound-induced basic protein, ethylene-responsive family protein, metallothionein-like protein cysteine proteinase inhibitor (cystatin) and Putative Kunitz trypsin protease inhibitor. An understanding of the roles of these differentially expressed genes will provide insights into the resistance mechanisms and candidate genes involved in soybean-M. javanica interaction and contribute to more effective control of this pathogen.

O trabalho teve como objetivo avaliar um sistema de micropropagação para a cultivar Prata-Anã, observando-se os principais fatores de eficiência e limitação no processo produtivo da muda. Os explantes foram estabelecidos em meio nutritivo MS, suplementado com 5mg/L de BAP (benzilaminopurina) e 30g/L de sacarose solidificado com 8g/L de ágar e pH ajustado em 5,7. A fase de multiplicação foi composta pelo mesmo meio de cultura e a de enraizamento constituída pela metade da concentração dos sais de MS e de sacarose, sem regulador de crescimento. Perdas por contaminação bacteriana foram maiores durante o estabelecimento in vitro e por fungos, nos dois últimos subcultivos. As maiores taxas de multiplicação ocorreram entre o 4º e o 5º subcultivos e, ao final do processo, observou-se maior proporção de brotos na classe entre 30 e 60mm. Com relação à eficiência da utilização da mão-de-obra no laboratório, observou-se que o processamento diário de frascos por operador foi baixo nas fases de estabelecimento, primeiro subcultivo e enraizamento, quando comparado com as fases de multiplicação exponencial dos explantes. Apesar de não terem sido constatadas perdas na fase de aclimatação, foi observada a ocorrência de 1% do total das plântulas com anomalias morfológicas.

The purpose of this work was to evaluate a micropropagation system to cultivar Prata-Anã, observing the main factors of efficiency and limitation in the plantlet production process. The explants were established in the medium MS, supplemented with 5mg/L BAP (benzilaminopurine), 30g/L sucrose, 8g/L agar and pH 5.7. The bud multiplication was carried out in the same medium described above and the plantlet rooting phase was done with half concentration of salt and sucrose, without plant growth regulator. Losses by bacterial contamination were higher during the in vitro establishment and by fungus in the last two subcultures. The highest multiplication rates occurred between the fourth and the fifth subcultures and at the end of the process it was observed higher proportion of plantlets between 30 and 60mm. In relation to the efficiency of the number of glasses processed per operator in the laboratory it was low in the establishment, phase first subculture and rooting, when compared with the exponential multiplication phase of the explants. Even though it was noticed losses in the acclimatization phase, it was observed the occurrence of 1% of plantlets with morphological variation.

Explantes de bananeira cv. Caipiras (AAA) foram cultivados in vitro. Nas subculturas de estabelecimento e multiplicação, o meio utilizado foi MS + 5 mg/l de BAP e, na de enraizamento, 50%MS sem BAP. Na avaliação das subculturas, a maior contaminação ocorreu no estabelecimento (74,7%), seguindo decrescente até o enraizamento, com 5,6%. O número de brotos por frasco diminui ao longo das subculturas, atingindo 3,7 brotos na subculturas 1 e 1,7 na subcultura 4. O tamanho dos brotos permaneceu entre 24 e 26 mm, nas subculturas de 1 a 3, diminuindo na subcultura 4, com 22 mm. Como conseqüência, a classe de brotos menores (x <FONT FACE=Symbol>£</FONT> 20 mm) predominou, variando de 56% na subcultura 1 para 65% na subcultura 4. No enraizamento, a predominância (62%) foi de brotos na faixa entre 30 e 60 mm, com média de 4,6 brotos por frasco. A avaliação geral do processo indicou um rendimento real de 70,9 mudas/rizoma.

Banana explants cv. Caipira (AAA) was cultivated in vitro. In the establishment and multiplication phases the medium used was MS+5mg/l BAP and in the rooting phase, 50%MS without BAP. In the subcultures evaluations, the highest contamination rate occurred at the establishment (74,7%), decreasing until rooting, with 5,6%. The number of shoots per flask along the subcultures was 3,7 in the first subculture and 1,7 in the fourth. The shoots' size remained between 24 and 26 mm in the subcultures 1 to 3, reducing in the subculture 4 with 22 mm. As a consequence, the class of smaller shoots (x <FONT FACE=Symbol>£</FONT> 20 mm) was predominant, from 56% in the subculture 1 to 65% in the subculture 4. During rooting, the predominance (62%) of shoots was between 30 and 60 mm, with 4,6 shoots per flask. The general evaluation of the process indicated an efficiency of 70,9 plantlets per rhizome.