Dehydrin-Like Proteins in Soybean Seeds in Response to Drought Stress during Seed Filling

There is no information on accumulation of dehydrin proteins during seed development and maturation of soybean [Glycine max (L.) Merr.] in response to drought stress. Our objective was to study accumulation of dehydrin-like proteins in developing soybean seeds in response to drought stress. A greenhouse experiment and a field experiment were conducted. In the greenhouse experiment, three treatments were imposed on soybean plants after beginning of linear seed filling (R5): well-watered (WW), gradual stress (GS) imposed before severe stress, and sudden severe stress (SS). In the field treatments were irrigation (I) and nonirrigation (NI) (rainfed) conditions imposed from R5 to R8 (mature seeds). Greenhouse results indicated dehydrin-like proteins (28 and 32 kDa) were detected 18 d after R5 (R5.8) in developing seeds from drought-stressed plants but not in seeds from the well-watered plants. In the mature seeds, dehydrin-like proteins (28, 32, and 34 kDa) were detected in seeds from drought-stressed plants as well as the well-watered plants. In the field, dehydrin-like proteins accumulated similarly under irrigation and nonirrigation conditions, with the first detection for dehydrins (28 and 32 kDa) at 22 d after R5 (R6). Accumulation of dehydrin-like proteins was maximal in seeds harvested at 43 d after R5 (seed physiological maturity)

Chromosome comparison between two species of Phyllostomus (Chiroptera - Phyllostomidae) from Eastern Amazonia, with some phylogenetic insights

The karyotypes of Phyllostomus discolor and P. hastatus from Eastern Amazonia were studied by G-, C-, G/C sequential and Ag-NOR techniques. Both species presented 2n = 32, with the autosome complement composed of 30 bi-armed in P. discolor and 28 bi-armed plus 1 acrocentric in P. hastatus. In both species, the X chromosome is medium submetacentric while the Y is minute acrocentric. The present study found only one difference between the karyotypes of P. discolor and P. hastatus: the smallest autosome (pair 15) is bi-armed in discolor and acrocentric in hastatus, a result best explained by pericentric inversion. The C-banding revealed constitutive heterochromatin only at the centromeric regions of all chromosomes, with the NOR site located at the distal region of short arm of pair 15, in both species. The taxon P. discolor is considered primitive for genus Phyllostomus and the bi-armed form of pair 15 is the assumed primitive condition which, rearranged by a pericentric inversion originated the acrocentric from found in P. hastatus.<br>Os cariótipos de Phyllostomus discolor e P. hastatus da Amazônia oriental são estudados por bandeamentos G, C, G/C sequencial e coloração Ag-NOR. Ambas as espécies apresentaram 2n = 32, sendo o complemento autossômico composto por 15 pares bi-armed em P. discolor e 14 bi-armed mais 1 par acrocêntrico em P. hastatus. O cromossomo X é um submetacêntrico médio e o Y é um pequeno acrocêntrico em ambas as espécies. O presente estudo encontrou apenas uma diferença entre os cariótipos de P. discolor e P. hastatus: o menor autossomo (par 15) é metacêntrico em discolor e acrocêntrico em hastatus. Este resultado é melhor explicado por uma inversão pericêntrica. O bandeamento C revelou heterocromatina constitutiva na região centromérica de todos os cromossomos, e os sítios NOR foram localizados na região distal do par 15, em ambas as espécies. O táxon P. discolor é considerado primitivo para o gênero Phyllostomus e supõe-se que a forma metacêntrica do par 15 seja a condição primitiva, que foi rearranjada por uma inversão pericêntrica, originando a forma acrocêntrica encontrada em P. hastatus