The enzyme Δ³,Δ²-dienoyl-CoA isomerase (ECI1) plays a crucial role in the mitochondrial β-oxidation of fatty acids with a double-bond in odd and even positions. The ECI1 gene might be a qualified candidate for studies pertaining to lipid deposition and meat quality in swine. In the present study, ECI1 cDNA of the Tibetan pig was obtained by in silico cloning and verified by PCR analysis. Single-nucleotide polymorphisms (SNPs) of ECI1 were screened by PCR-sequencing and genotypes of those SNPs were tested by PCR-restriction fragment length polymorphism (PCR-RFLP) in Diannan small-ear pigs (DSP, n=40), Tibetan pigs (TP, n=60) and Yorkshire pigs (YP, n=30). The expression levels of ECI1 were analyzed by real-time quantitative PCR and Western blotting in tissues of the liver, backfat, and longissimus dorsi (LD) muscle of DSP (n=8), TP (n=8) and YP (n=8). Single factor linear correlation analysis was applied separately for each breed to evaluate correlations between ECI1 gene expression in the LD muscle and intramuscular fat (IMF) content. We obtained an ECI1 gene length of 1 401 bp from the cDNA that contained a full coding region of 909 bp. Three novel SNPs (g.42425337G>A; g.42424666A>G; and g.42422755A>G) were detected, and only g.42424666A>G exhibited three genotypes among the three breeds. The ECI1 expression levels in the LD muscle of DSP and TP were significantly higher than that of YP (P<0.05). Moreover, TP had the highest ECI1 expression in backfat (P<0.01), and a positive correlation was observed between gene expression and IMF content. The results suggest that differences in ECI1 gene expression might be related to lipid deposition and meat quality in pig.

Drought stress is a major abiotic stress of common bean (Phaseolus vulgaris L.) throughout the world. Increasing the proline accumulation contributes to enhance crop drought tolerance. A cDNA for δ-ornithine aminotransferase (δ-OAT), an enzyme involved in the biosynthesis of proline, was isolated from Phaseolus vulgaris (PvOAT). PvOAT exhibits 87.4 and 39.8% similarity of the deduced amino acid sequences with δ-OAT from Glycine max and Vigna aconitifolia, respectively. The transcriptional analysis revealed that PvOAT was strongly induced by drought stress. And the expression of PvOAT was higher in leaves than that in the root and stem of common bean by drought stress. Similar increase of the proline accumulation was observed in leaves and roots of common bean by drought stress. Furthermore, the proline content, the PvOAT expression and the PvOAT enzyme activity in cultivar F5575 was significantly (P<0.01) higher than that in cultivar F4851 under drought-stress conditions. Interestingly, it had been observed that, in the later stage of drought stress, the proline steadily maintained at the maximum level maybe result from the PvOAT enzyme activity increasing steadily. These results indicated that the expression of PvOAT and the accumulation of proline induced by drought stress treatment were related to the degree of common bean drought tolerance. So our results support the view that δ-OAT is associated with proline synthesis under drought stress conditions.