The mutation of the gene encoding a stearoyl-acyl carrier protein fatty acid desaturase (ssi2) has been proved to enhance pathogen resistance in several plants, while it’s potential to regulate biotic and abiotic stresses in wheat is still unclear.  In this study, we cloned TaSSI2 gene in wheat and provided several evidences of its involvement in multiple biological functions.  By using barley stripe mosaic virus (BSMV)-induced gene silencing (VIGS) in wheat, it was found that TaSSI2 negatively regulated both powdery mildew and Fusarium head blight (FHB) resistance, which was consistent with the phenotype observed in knock-out mutants of Kronos.  The expression of TaSSI2 was down-regulated by in vitro treatments of methyl jasmonate (MeJA), but positively regulated by salicylic acid (SA) and abscisic acid (ABA), implying the cross-talk between different hormone signaling pathways involved in wheat to regulate biotic stresses is still to be elucidated.  Furthermore, the up-regulated expression of PR4 and PR5 indicated that TaSSI2 probably regulated FHB resistance by depressing the SA signaling pathway in wheat.  In addition, the over-expression of TaSSI2 increased the content of linolenic acid (18:3) and subsequently enhanced drought tolerance of transgenic Brachypodium.  This phenomenon might be associated with its subcellular localization in the whole cytosol, partly overlapping with Golgi apparatus and the secreted vesicles.  As a stearoyl-acyl carrier protein fatty acid desaturase, TaSSI2 was proposed to be involved in cell lipid metabolism and carried targets out of the cell from membrane or wax synthesis, resulting in enhanced drought tolerance in plant.

Follistatin (FS) is a secreted protein, which was originally isolated from porcine follicular fluid. Expression of follistatin is tightly regulated during porcine growth and development. To study the essential transcriptional regions of the porcine FS promoter, ten primer pairs were designed to amplify segments with different lengths of the FS promoter from –1 800 to +16 bp. The products were then inserted into the pGL3-basic vector to analyze the relative luciferase activity. The results showed that the most remarkable changes of promoter activity were observed between constructs (–302/+16 bp)-FS and (–180/+16 bp)-FS (P<0.01). Further research showed that the reconstructed reporter plasmid lacking myeloid zinc finger 1 (MZF1) binding sequence had significantly decreased luciferase activity (P<0.05). Furthermore, the FS protein expression was significantly increased in PK15 cells while the MZF1 was overexpressed, suggesting that the short sequence “TCCCCACC” (the recognition site of transcription factor MZF1) was the most important for FS transcription activation in the porcine.

To determine the genetic diversity and population structure of sweet potato accessions cultivated in China, and to establish the genetic relationships among their germplasm types, a representative collection of 240 accessions was analyzed using inter-simple sequence repeat (ISSR) markers. The mean genetic similarity coefficient, Nei’s gene diversity, and shared allele distance of tested sweet potato accessions were 0.7302, 0.3167 and 0.2698, respectively. The 240 accessions could be divided into six subgroups and five subpopulations based on neighbor-joining (NJ) clustering and STRUCTURE results, and obvious genetic relationships among the tested sweet potato accessions were identified. The marker-based NJ clustering and population structure showed no distinct assignment pattern corresponding to flesh color or geographical ecotype of the tested sweet potato germplasm. Analysis of molecular variance (AMOVA) revealed small but significant difference between white and orange-fleshed sweet potato accessions. Small but significant difference were also observed among sweet potato accessions from the Southern summer-autumn sweet potato region, the Yellow River Basin spring and summer sweet potato region and the Yangtze River Basin summer sweet potato region. This study demonstrates that genetic diversity in the tested sweet potato germplasm collection in China is lower than that in some reported sweet potato germplasm collections from other regions. Pedigree investigations suggest that more diverse Chinese sweet potato varieties should be formed by broadening the selection scope of breeding parents and incorporating the introduced varieties into future breeding programs.

Huahui 1 is an elite transgenic male sterile restorer line of wild rice abortive-type that expresses a Bacillus thuringiensis (Bt) δ-endotoxin and provides effective and economic control of lepidopteran insects. To exploit Huahui 1 to develop a new Bt rice, the insertion site of the Bt gene was determined by thermal asymmetric interlaced PCR (TAIL-PCR). Bt was located in the promoter region of LOC.Os10g10360, approximately 5.35 Mb from the telomere of the short arm of chromosome 10. For the first time, a Bt cytoplasmic male sterile (CMS) system was developed by introgressing Bt from Huahui 1. The recipient CMS system used consisted of Indonesia paddy rice-type II-32B (maintainer line) and II-32A (male sterile line). Marker-assisted selection was used to increase selection efficiency in the backcrossing program. In BC5F1, the Bt plant 85015-8 was selected for further analyses, as it had the highest SSR marker homozygosity. In addition, the linkage drag of the foreign Bt gene in 85015-8 was minimized to 8.01-11.46 Mb. The foreign Bt gene was then delivered from 85015-8 into II-32A. The resultant Bt II-32A and Bt II-32B lines were both resistant to lepidopteran in field trials, and agronomic traits were not disturbed. The maintainability of II-32B, and the male sterility and general combining ability of II-32A, were not affected by the Bt introgression. This study demonstrates a simple and fast approach to develop Bt hybrid rice.

To investigate the tissue deposition and elimination of melamine (MEL) in broilers, a total of 1 920 commercial 1-d-old male Cobb broilers were randomly allotted to 6 treatments with diets contaminated by MEL at 0, 2, 10, 30, 50, 100 mg kg-1 of diet for 42 d, and followed MEL withdrawal from diet at 50 or 100 mg kg-1 of diet for 96 h. The MEL was found in residue of plasma, liver, kidney, breast, and leg muscle with the highest level in kidney and in dose response manner (except in kidney), but no time response (except in plasma). The MEL residue in organ tissue was below the safe level of 50 μg mL-1 in blood or 50 μg kg-1 in tissues proposed by the US FSIS when MEL in diet was lower (2 mg kg-1). The MEL in tissues was eliminated by withdrawal MEL from diets. The elimination half-life of MEL was from 3.2 to 6.6 h, and the clearance time, when MEL residue concentration under limit detection, was from 18.0 to 31.4 h.