Identification and characterization of microRNAs in the ovaries of multiple and uniparous goats (Capra hircus) during follicular phase.

BACKGROUND: Superior kidding rate is an important economic trait in production of meat goat, and ovulation rate is the precondition of kidding rate. MicroRNAs (miRNAs) play critical roles in almost all ovarian biological processes, including folliculogenesis, follicle development, follicle atresia, luteal development and regression. To find out the different ovarian activity and follicle recruitment with miRNA-mediated posttranscriptional regulation, the small RNAs expressed pattern in the ovarian tissues of multiple and uniparous Anhui White goats during follicular phase was analyzed using Solexa sequencing data. RESULTS: 1008 miRNAs co-expressed, 309 and 433 miRNAs specifically expressed in the ovaries of multiple and uniparous goats during follicular phase were identified. The 10 most highly expressed miRNAs in the multiple library were also the highest expressed in the uniparous library, and there were no significantly different between each other. The highest specific expressed miRNA in the multiple library was miR-29c, and the one in the uniparous library was miR-6406. 35 novel miRNAs were predicted in total. GO annotation and KEGG Pathway analyses were implemented on target genes of all miRNA in two libraries. RT-PCR was applied to detect the expression level of 5 randomly selected miRNAs in multiple and uniparous hircine ovaries, and the results were consistent with the Solexa sequencing data. CONCLUSIONS: In the present study, the different expression of miRNAs in the ovaries of multiple and uniparous goats during follicular phase were characterized and investigated using deep sequencing technology. The result will help to further understand the role of miRNAs in kidding rate regulation and also may help to identify miRNAs which could be potentially used to increase hircine ovulation rate and kidding rate in the future.

Effects of non-uniform root zone salinity on growth, ion regulation, and antioxidant defense system in two alfalfa cultivars.

A split-root system was established to investigate the effects of uniform (0/0, 50/50, and 200/200 mM salt [NaCl]) and non-uniform (0/200 and 50/200 mM NaCl) salt stress on growth, ion regulation, and the antioxidant defense system of alfalfa (Medicago sativa) by comparing a salt-tolerant (Zhongmu No.1) and salt-sensitive (Algonquin) cultivar. We found that non-uniform salinity was associated with greater plant growth rate and shoot dry weight, lower leaf Na+ concentration, higher leaf potassium cation (K+) concentration, lower lipid peroxidation, and greater superoxide dismutase (EC 1.15.1.1), catalase (EC 1.11.1.6), and peroxidase (EC 1.11.1.7) activities, compared to uniform salt stress in both alfalfa cultivars. Under non-uniform salinity, a significant increase in Na+ concentration and Na+ efflux and a decline in K+ efflux in the no-saline or low-saline part of the roots alleviated salt damage. Our results also demonstrated that proline and antioxidant enzymes accumulated in both the no- or low-saline and high-saline roots, revealing that osmotic adjustment and antioxidant defense had systemic rather than localized effects in alfalfa plants, and there was a functional equilibrium within the root system under non-uniform salt stress. The salt-tolerant cultivar Zhongmu No.1 exhibited greater levels of growth compared to Algonquin under both uniform and non-uniform salt stress, with Na+ tolerance and efflux abilities more effective and greater antioxidant defense capacity evident for cultivar Zhongmu No.1.