Heritability of the resistance to pepper huasteco yellow vein virus in wild genotypes of <Emphasis Type="Italic">Capsicum annuum</Emphasis>

Pepper huasteco yellow vein virus (PHYVV) is the main virus of pepper crop in Mexico. No resistant cultivars are available and resistance breeding is hampered by the lack of knowledge of heritability (h ²) of PHYVV resistance. This is a continuation of previous studies and the objectives were to analyze the h ² and the behavior of the resistant trait to PHYVV. Four resistant assays were done with three resistant wild lines (UAS12, UAS13 and UAS10) of Capsicum annuum in the S4, S5, S6 and S7 generation under greenhouse conditions. Plants from all tests were inoculated with PHYVV through Bemisia tabaci. Line UAS12 was the most resistant showing a significantly proportion of resistant plants, less disease symptoms and longer incubation time, followed by the lines UAS13 and UAS10 in all assays. Distribution of symptoms showed a bimodal tendency in all the trials, suggesting that two groups of genes are involved in this resistance trait. The lines UAS12, UAS13 and UAS10 showed the same pattern of response to selection with an average of h ² of 0.17, 0.06, 0.02 and 0.00 in the S4, S5, S6 and S7, respectively. These results indicate that all lines responded positively to the selection in the S4, S5 and S6, whereas in the S7 there was no response by the possible exhaustion of variation. Line UAS12 is the most promising genotype and the lines UAS13 and UAS10 are genetic resources that can be supplemented to breed the resistance of PHYVV. These results provides basic information for resistance breeding.     

Sensitivity of Seeds to Chemical Mutagens,Detection of DNA Polymorphisms and Agro-Metrical Traits in M1 Generation of Coffee (Coffea arabica L.)

Journal of Crop Science and Biotechnology - Coffee (Coffea Arabica L.) is threatened by biotic and abiotic stresses. Nevertheless, the breeding of Arabica coffee is restricted due to its low...     

Black carbon estimation in French calcareous soils using chemo‐thermal oxidation method

We studied the black carbon (BC) content of ca. 405 samples from French topsoil and artificial soil and carbonate mixtures. Our protocol involved three main steps: (i) decarbonation by HCl, (ii) elimination of non‐pyrogenic organic carbon in a furnace at 375 °C, and (iii) quantification of residual carbon by CHN analysis. BC content increased for calcareous soils according to their carbonates content. Subsequent analyses confirmed the existence of a methodological artefact for BC determination only in calcareous soils. Decarbonation changes the thermal properties of organic matter, creating more recalcitrant carbon than in the initial sample. Higher CaCO₃ and organic carbon content results in a more pronounced artefact. The reversal of the first two steps of the chemo‐thermal oxidation method (i.e. thermal oxidation before soil decarbonation) eliminates this artefact. Overall, our results suggest that BC content may have been overestimated in a large number of studies on calcareous soils.     

Abscisic Acid May Alter the Salicylic Acid‐Related Abiotic Stress Response in Maize

The effect of 0, 0.05 or 0.1 mm abscisic acid treatment on chilling tolerance and salicylic acid‐related responses was investigated in young maize seedlings (Zea mays L., hybrid Norma). Although the pre‐treatment of maize seedlings with abscisic acid slightly decreased the chlorophyll content, it also reduced the level of chilling injury caused by 6 days of cold treatment at 5 °C. Under normal growth conditions, increased levels of bound salicylic acid and of bound ortho‐hydroxycinnamic acid were observed in the leaves during abscisic acid treatment. In the roots, abscisic acid did not affect the free and bound salicylic acid levels, but increased the amount of free and bound ortho‐hydroxycinnamic acid. The activity of glutathione‐S‐transferase increased on the 3rd day of abscisic acid treatment, whereas it did not change when followed by cold stress, compared with the control leaves. In the roots, the activities of glutathione reductase, glutathione‐S‐transferase and ascorbate peroxidase increased during the abscisic acid treatment, and those of glutathione‐S‐transferase and ascorbate peroxidase were also stimulated when abscisic acid pre‐treatment was followed by cold stress, compared with the control roots. Our results suggest that an overlap may exist between the abscisic acid‐induced cold acclimation and the salicylic acid‐related stress response.     

车前子提取物抑制扑热息痛诱导小鼠肝损伤的作用研究

【目的】研究车前子提取物干预扑热息痛(Acetaminophen,APAP)引起小鼠肝损伤的作用,并探究其潜在作用机制。【方法】运用半仿生酶法提取车前子活性成分,采用液相色谱-质谱联用(LC-MS)检测其主要成分。体内研究车前子提取物对APAP肝损伤的保护作用,将60只雌性昆明小白鼠随机分为正常对照组(NC)、APAP肝损伤模型组(LD)、车前子对照组(PA)以及APAP干预的车前子提取物高、中、低剂量组(HPA+LC、MPA+LD、LPA+LD)。其中NC组和LD组小鼠灌胃生理盐水、PA组小鼠灌胃200μg/mL车前子提取物,HPA+LD,MPA+LD和LPA+LD组小鼠分别灌胃车前子提取物200,100,50μg/mL,每天2次,连续6 d;末次给药12 h后,采血并分离肝脏,检测血清谷丙转氨酶(ALT)和谷草转氨酶(AST)活性,评价肝脏损伤程度;检测肝脏中超氧化物歧化酶(SOD)活性及谷胱甘肽(GSH)、过氧化氢(H_2O_2)和丙二醛(MDA)含量,评价肝脏的氧化应激程度;检测CYP2E1 mRNA和蛋白表达,并通过细胞色素P450酶2E1(Cytochrome 2E1,CYP2E1)法体外筛选车前子抗APAP肝损伤可能的有效成分。【结果】LC-MS检测发现,车前子提取物有37种主要成分;血清生化指标检测发现,不同剂量的车前子提取物明显减少APAP诱导的氧化产物,增强抗氧化防御能力,减轻肝脏损伤且呈剂量依赖性;车前子提取物显著降低CYP2E1 mRNA和蛋白表达,说明车前子抑制CYP2E1的活性;车前子提取物中抗APAP肝损伤的有效成分为车前草苷D、车前草苷E、高车前素和高车前苷。【结论】车前子提取物的有效成分为车前草苷D、车前草苷E、高车前素和高车前苷。车前子提取物对APAP诱导的肝损伤具有保护作用,其潜在作用机制可能与抑制肝脏CYP2E1的表达和活性有关。