Genomic insights into the evolutionary history and diversification of bulb traits in garlic.

BACKGROUND: Garlic is an entirely sterile crop with important value as a vegetable, condiment, and medicine. However, the evolutionary history of garlic remains largely unknown. RESULTS: Here we report a comprehensive map of garlic genomic variation, consisting of amazingly 129.4 million variations. Evolutionary analysis indicates that the garlic population diverged at least 100,000 years ago, and the two groups cultivated in China were domesticated from two independent routes. Consequently, 15.0 and 17.5% of genes underwent an expression change in two cultivated groups, causing a reshaping of their transcriptomic architecture. Furthermore, we find independent domestication leads to few overlaps of deleterious substitutions in these two groups due to separate accumulation and selection-based removal. By analysis of selective sweeps, genome-wide trait associations and associated transcriptomic analysis, we uncover differential selections for the bulb traits in these two garlic groups during their domestication. CONCLUSIONS: This study provides valuable resources for garlic genomics-based breeding, and comprehensive insights into the evolutionary history of this clonal-propagated crop.

The effect of cultivar, sowing date and transplant location in field on bolting of Welsh onion (Allium fistulosum L.).

BACKGROUND: Bolting reduces the quality and commercial yield of Welsh onion (Allium fistulosum L.) in production. However, seed production is directly dependent on flower induction and bolting. The Welsh onion belongs to the green plant vernalisation type, specific seedling characteristics and sufficient accumulated time at low temperature are indispensible for the completion of its vernalisation process. Only if these conditions for vernalisation are fulfilled, the plants will bolt in the following year. The present investigation evaluated the effects of cultivar, sowing date and transplant location in field on the bolting of Welsh onion at the Horticultural Farm of the College of Horticulture, Northwest A&F University, Yangling, Shannxi Province, China in two succeeding production years: 2010-2011 and 2011-2012. A strip split plot layout within a randomised complete block design with three replications was used. RESULTS: The results revealed that all three factors (cultivar, sowing date and transplant location) and their interaction had significant effects on the initiation and final rate of bolting observed by 30 April. The earliest bolting date (14 February, 2011 and 15 February, 2012) and the highest bolting rate (100% in 2011 and 62% in 2012) occurred when the JinGuan cultivar was sown on 20 August and transplanted in a plastic tunnel, whereas the latest date and lowest rate (no bolting observed until 30 April) of bolting occurred when the XiaHei cultivar was sown on 29 September and transplanted in an open field. CONCLUSIONS: These results suggest that we can control bolting in Welsh onion production by choosing an appropriate cultivar, sowing date and transplant location. Choosing a late bolting cultivar, such as cultivar XiaHei, sowing around October, and transplanting in the open field can significantly delay bolting, while a sowing date in late August should be selected for seed production, and the seedlings should be transplanted in a plastic tunnel to accelerate development of the flower buds.

A high ratio of dietary n-3/n-6 polyunsaturated fatty acids improves obesity-linked inflammation and insulin resistance through suppressing activation of TLR4 in SD rats.

Dietary ratios of n-3/n-6 polyunsaturated fatty acids (PUFAs) have been implicated in controlling markers of metabolic disorders, including obesity, insulin resistance (IR), inflammation, and lipid profiles, which are also presumed to be partly related to type 2 diabetes mellitus (T2DM). However, molecular mechanisms of the different PUFAs related to metabolic disorders have not been systematically addressed. The present study aimed to investigate the impact of dietary n-3/n-6 PUFA ratios on obesity and IR and, further, to determine the underlying mechanisms. For 16 weeks, 32 SD male rats, randomly divided into four groups (n = 8 per group), received one of the following diets: normal chow, high saturated fatty acid (SFA), high n-3/n-6 PUFA ratio (1∶1, PUFA¹:¹), or low n-3/n-6 PUFA ratio (1∶4, PUFA¹:4). Following the experimental diet period, metabolic parameters related to obesity and IR were measured. Compared to SFA diet-fed rats, PUFA¹:¹ diet-fed rats exhibited decreased body and visceral fat weight, lowered blood lipids, and improved glucose tolerance and insulin sensitivity. Interestingly, these changes were accompanied with decreased expression levels of circulating pro-inflammatory cytokines, including tumor necrosis factor α, interleukin-6, and C-reactive protein. Moreover, the TLR4 protein and mRNA levels were markedly down-regulated by PUFA¹:¹ compared with SFA; however, PUFA¹:4 diet-fed rats failed to exhibit these changes. Cumulatively, our data highlight a role for a PUFA¹:¹ diet in the prevention of obesity and related metabolic disorders by suppressing the activation of TLR4, a critical modulator of pro-inflammatory cytokines.

[Effects of dietary different ratios of high n - 3/n - 6 polyunsaturated fatty acids on insulin resistance in rats].

OBJECTIVE: To study the effects of dietary different ratios of high-fat n - 3/ n - 6 polyunsaturated fatty acids (PUFAs) on insulin sensitivity and pro-inflammatory cytokines expression in serum of rats. METHODS: 40 young male SD rats (n = 10) after adaptive feeding 7d were randomly divided into 4 groups, fed by common diet, high fat diet, high fat with n - 3/n - 6 1 : 1 PUFAs diet, and high fat with n - 3/n - 6 1 : 4 PUFAs diet. The animals were weighted weekly and sacrificed at 16 weeks, then blood lipids, serum insulin sensitivity and pro-inflammatory cytokines (IL-6, TNF-alpha and hs-CRP) were determined. RESULTS: Compared with normal control group, three high fat groups result in a significant increase of body weight gain. Insulin sensitivity of high fat 1 : 1 group had no significant difference with normal control, but is significantly higher than high-fat and high-fat 1 : 4 group (P < 0.05). Compared with high fat group, pro-inflammatory cytokines expression of high fat 1 : 1 group decreased significantly (P < 0.05). CONCLUSION: High dietary polyunsaturated fatty acids appears associated with a trend towards obesity risk, however, increase of the proportion of n - 3 PUFAs dietary composition effectively decreased the expression of pro-inflammatory cytokines, then, improved insulin sensitivity and prevented insulin resistance.

Effects of dietary fish oil on learning function and apoptosis of hippocampal pyramidal neurons in streptozotocin-diabetic rats.

Previous research has demonstrated that diabetes induces learning and memory deficits. However, the mechanism of memory impairment induced by diabetes is poorly understood. Dietary fatty acids, especially polyunsaturated fatty acids, have been shown to enhance learning and memory and prevent memory deficits in various experimental conditions. The present study investigated the effects of fish oil supplementation on the neuron apoptosis in the hippocampus of streptozotocin (STZ)-induced diabetes rats. The effects of diabetes and fish oil treatment on the spatial learning and memory were also evaluated using the Morris Water Maze. Diabetes impaired spatial learning and memory of rats. Diabetes increased the expression of Bax and caspase-3, which led the apoptosis of the CA1 pyramidal neurons, and further contributed to the deficits in learning and memory processing. Fish oil dietary supplementation in diabetic rats conducts neuron-protective function through an anti-apoptotic pathway and significantly improves the ability of learning and memory. These results partially explain the mechanism of the effect of diabetes and fish oil treatment on learning and memory, supporting a potential role for fish oil as an adjuvant therapy for the prevention and treatment of diabetic complications.

Effect of calcium on the proliferation and differentiation of murine corneal epithelial cells in vitro.

AIM: To investigate the effect of calcium on the proliferation and differentiation of murine corneal epithelial cells in vitro. METHODS: Mouse corneal epithelial cells were cultured in serum-free low-Ca(2+) medium (KSFM) and KSFM supplemented with 0.9mmol/L Ca(2+). Population doublings (PDs) were determined. The expression of corneal epithelial cell markers p63, keratin 19 (K19) and involucrin was investigated by RT-PCR analysis and semiquantitative analysis of Western blotting. RESULTS: Cells in KSFM were stably subcultured over 25 passages, however, none of the cell lines could pass P4 in KSFM with Ca(2+). In KSFM, the cells was were homogeneous and small cells with typical cobblestone appearance; and expressed p63, K19 and involucrin. After medium was supplemented with calcium, cells became a heterogeneous mix of small and large cells. Furthermore, semiquantitative analysis of Western blotting showed that the expression of involucrin was increased significantly. CONCLUSION: Calcium has the effect of inhibiting proliferation and triggering differentiation on mouse corneal epithelial cells.

[Effects of dietary different ratios of n-3 to n-6 polyunsaturated fatty acids influence lipid metabolism and appetite of rats].

OBJECTIVE: To study the effects of dietary different ratios of n-3 to n-6 polyunsaturated fatty acids on food intake of SD rats and potential mechanisms. METHODS: According to their serum total cholesterol level, male rats were randomly divided into 6 groups, and were fed common feed diet, high fat diet, high fat with n-3/n-6 1:1 PUFA diet, high fat with n-3/n-6 1:5 PUFA diet, common feed with n-3/n-6 1:1 PUFA diet, and common feed with n-3/n-6 1:5 PUFA diet, respectively. Weights were measured about every 6 days, and food intake were measured everyday. At 0, 15, 30 and 45 days, triglycerides (TG) and total cholesterol (TC) in the plasma were measured using kits. After 45 days, the rats were sacrificed. RT-PCR was used for measuring the expression of neuropepide Y (NPY) and AMP-activated protein kinase-alpha2 (AMPK-alpha2) mRNA in the hypothalamus. RESULTS: Four diets with any ratio of n-3/n-6 PUFA resulted in significant restraint of body weight gain, TC and TG level in the plasma, NPY and AMPK-alpha2 mRNA level in the hypothalamus compared to high fat diets (P < 0.05). These situations in two groups with common diet and one group with high diet added 1:1 PUFA are more significant than the high fat diet group. CONCLUSION: These results indicate that dietary PUFA improved lipid metabolism which may be related with appetite control through AMPK path.