Overexpression of an aquaporin protein from Aspergillus glaucus confers salt tolerance in transgenic soybean.

Salt stress is an important abiotic factor that causes severe losses in soybean yield and quality. Therefore, breeding salt-tolerant soybean germplasm resources via genetic engineering has gained importance. Aspergillus glaucus, a halophilic fungus that exhibits significant tolerance to salt, carries the gene AgGlpF. In this study, we used the soybean cotyledonary node transformation method to transfer the AgGlpF gene into the genome of the soybean variety Williams 82 to generate salt-tolerant transgenic soybean varieties. The results of PCR, Southern blot, ddPCR, and RT-PCR indicated that AgGlpF was successfully integrated into the soybean genome and stably expressed. When subjected to salt stress conditions via treatment with 250 mM NaCl for 3 d, the transgenic soybean plants showed significant tolerance compared with wild-type plants, which exhibited withering symptoms and leaf abscission after 9 d. The results of this study indicated that the transfer of AgGlpF into the genome of soybean plants produced transgenic soybean with significantly improved salt stress tolerance.

Cobitis xui, a new species of spined loach (Teleostei: Cobitidae) from the Pearl River drainage in southern China.

A new spined loach of the genus Cobitis Linnaeus is described from the Buquan River, located in Guangxi Zhuang Autonomous Region, China. The species differs from other members of Cobitis in China by a combination of morphological characters, none of them unique: body depth 14.3‒18.4% SL; lamina circularis long and knife-shaped; Gambetta zones present on the dorsolateral sides of the body (L1‒L5); 8‒11 large transverse elongated blotches on L5; 9‒12 large transverse elongated blotches on L1; maxillary barbels longer than eye diameter; 4‒5 narrow rows of dark spots on the caudal fin; caudal fin with 14 branched rays; a rectangular spot slightly smaller than eye diameter on the upper side of caudal fin base; and caudal-peduncle depth 79.5‒93.1% its length.

[Fish population structure in the fishway of Changzhou hydro-junction].

The fishway of Changzhou hydro-junction, located in the main stream of Xijiang River, is the biggest fishway in China up to now. Efficiency assessment of the Changzhou fishway is important for fish resource and ecosystem protection of the Pearl River, and can provide basic data for design, construction and management of other fishways in China. A total of 40 fish species in the Changzhou fishway were sampled on 11 occasions from April to June during 2011-2014 by using blocking method. Migratory species such as marbled eel, eel, Fugu ocellatus and the four domestic fish ( black carp, grass carp, silver carp and bighead carp) appeared in the fishway. The dominant species included Pelteobagrus vachelli (29.1%), Spualiobarbus' curriculus (16.8%), Hemiculter leucisculus (14.7%), Pseudolaubuca sinensis (12.0%), Squalidus argentatus (10.8%), Anguilla japonica (7.3%) and Cirrhinus molitorella (2.7%). Species accumulation curve indicated that up to 61 species would be monitored in the fishway with increasing the sampling frequency, indicating its good passage efficiency. Fish diversity in the Changzhou fishway was significantly lower than that in the downstream in Xijiang River, and two dominant species in the downstream of the Changzhou Dam, Megalobrama hoffmanni and Mystus guttatus, were not monitored in the fishway in this study, revealing that attraction efficiency of the fishway was different for different fish species. The canonical correspondence analysis showed that dam water level was the most important factor for the fishway effectiveness, it was necessary to adjust the operation mode of the Changzhou dam to instigate more fish migration by the fishway. According to the present situation of fishery resources of the Pearl River, it was suggested to include four domestic fish, M. hoffmanni, S. curriculus and C. molitorella as target species of the Changzhou fishway, and consider more about ecological characteristics of these species.

Spatiotemporal patterns of the fish assemblages downstream of the Gezhouba Dam on the Yangtze River.

An explicit demonstration of the changes in fish assemblages is required to reveal the influence of damming on fish species. However, information from which to draw general conclusions regarding changes in fish assemblages is insufficient because of the limitations of available approaches. We used a combination of acoustic surveys, gillnet sampling, and geostatistical simulations to document the spatiotemporal variations in the fish assemblages downstream of the Gezhouba Dam, before and after the third impoundment of Three Gorges Reservoir (TGR). To conduct a hydroacoustic identification of individual species, we matched the size distributions of the fishes captured by gillnet with those of the acoustic surveys. An optimum threshold of target strength of -50 dB re 1 m(2) was defined, and acoustic surveys were purposefully extended to the selected fish assemblages (i.e., endemic Coreius species) that was acquired by the size and species selectivity of the gillnet sampling. The relative proportion of fish species in acoustic surveys was allocated based on the composition (%) of the harvest in the gillnet surveys. Geostatistical simulations were likewise used to generate spatial patterns of fish distribution, and to determine the absolute abundance of the selected fish assemblages. We observed both the species composition and the spatial distribution of the selected fish assemblages changed significantly after implementation of new flow regulation in the TGR, wherein an immediate sharp population decline in the Coreius occurred. Our results strongly suggested that the new flow regulation in the TGR impoundment adversely affected downstream fish species, particularly the endemic Coreius species. To determine the factors responsible for the decline, we associated the variation in the fish assemblage patterns with changes in the environment and determined that substrate erosion resulting from trapping practices in the TGR likely played a key role.