ABSTRACT. The black locust (Robinia pseudoacacia) is a forest legume that is highly valued as a honey plant and for its wood. We explored the effect of short-term spaceflight on development of R. pseudoacacia seedlings derived from seeds that endured a 15-day flight; the genetic diversity and variation of plants sampled from spacemutagenized seeds were compared to plants from parallel groundbased control seeds using molecular markers and morphological traits. In the morphology analysis, the space-mutagenized group had 4269 ©FUNPEC-RP www.funpecrp.com.br Genetics and Molecular Research 11 (4): 4268-4277 (2012) Genetic diversity and variation of Robinia pseudoacacia apparent variation compared with the control group in morphological traits, including plant height, basal diameter, number of branches, branch stipular thorn length, branch stipular thorn middle width, leaflet vertex angle, and tippy leaf vertex angle. Simple sequence repeat (SSR) and sequence-related amplified polymorphism (SRAP) molecular marker analyses showed a slightly higher levels of genetic diversity in the space-mutagenized group compared to the control group. In the SRAP analysis, the space-mutagenized group had 115 polymorphic bands vs 98 in the controls; 91.27% polymorphic loci vs 77.78% in the controls; 1.9127 ± 0.2834 alleles vs 1.7778 ± 0.4174 in the controls; Nei's genetic diversity (h) was 0.2930 ± 0.1631 vs 0.2688 ± 0.1862 in the controls, and the Shannon's information index (I) was 0.4452 ± 0.2177 vs 0.4031 ± 0.2596 in the controls. The number of alleles was significantly higher in the space-mutagenized group. In the SSR analysis, the space-mutagenized group also had more polymorphic bands (51 vs 46), a greater percentage of polymorphic loci (89.47% vs 80.70%); h was also higher (0.2534 ± 0.1533 vs 0.2240 ± 0.1743), as was I (0.3980 ± 0.2069 vs 0.3501 ± 0.2412). These results demonstrated that the range of genetic variation in the populations of R. pseudoacacia increased after spaceflight. It also suggested that the SSR and SRAP markers are effective markers for studying mutations and genetic diversity in R. pseudoacacia. The data provide valuable molecular evidence for the effects of the space environment on R. pseudoacacia and may contribute to future spacebreeding programs involving forest trees.

ABSTRACT. Japanese scallop (Mizuhopecten yessoensis) is a coldwater shellfish, and a species of economic importance in China. In this study, we developed and evaluated simple sequence repeat (SSR) markers from the expressed sequence tags (ESTs) of M. yessoensis. The characteristics of 12 EST-SSR loci were investigated in 30 individual scallops, and the result revealed that the number of alleles per locus ranged from 2-4, with an observed heterozygosity ranging from 0.0333-0.7692, and an expected heterozygosity ranging from 0.0333-0.6312. Only two loci were found to depart significantly from the HardyWeinberg equilibrium (P < 0.05). The result of our study suggested that these markers could be considered as potential markers for studying the population structure of M. yessoensis and its intraspecific variation. The Japanese scallop Mizuhopecten yessoensis is a cold-water shellfish, and its original habitat is distributed across various regions of the world, including the northern part of Japan, the far eastern part of Russia, and the eastern part of the Korean Peninsula. Due to its large body mass, good taste, and nutritional value, M. yessoensis has become a high-value food. In 1983, M. yessoensis was introduced to China from Japan, and since then much research effort has focused on the development of better techniques for cultivating this species of scallop. However, despite increased cultivation, recent declines in quality and yield have prompted many studies on the genetic diversity of M. yessoensis (Wang et al., 2009;Liu et al., 2010) to address concerns regarding its protection and genetic diversity in the hope of preventing a decline in its population.Few studies have used DNA-based methods to study the population structure of M. yessoensis (Sato et al., 2005;Wang et al., 2009). Microsatellite DNAs, also known as simple sequence repeats (SSRs), are short (1-6 bp in length) tandem-repeat sequences that are widely dispersed in eukaryotic genomes. SSRs have been extensively used to study the genetic diversity and population structure of many species because of their high level of polymorphisms, co-dominant inheritance, and distribution throughout the genome (Xu et al., 2010;Yang et al., 2011;Zheng et al., 2012). Expressed sequence tags (ESTs) represent part of the transcribed genome of an organism and are an important resource for identifying microsatellites . In this study, we identified the microsatellites from M. yessoensis ESTs and analyzed the polymorphisms present in the EST-SSRs.The SSRs of M. yessoensis genome were obtained by screening 3009 M. yessoensis ESTs obtained in our laboratory and 4711 M. yessoensis ESTs obtained from GenBank (at http://www.ncbi.nlm.nih.gov/Genbank/). The SSR sequences were identified using the software MISA (http://pgrc.ipk-gatersleben.de/misa/) and 58 of these EST-SSRs were randomly selected for polymerase chain reaction (PCR) using M. yessoensis genomic DNA as template. PCR primers were designed using the Primer 5.0 software with default parameters.M. yessoensis genomic D...