家畜自然抗病力的遗传控制和培育(下)

四、家畜的自然抗病力及其研究方法研究家畜遗传性的自然抗病力,关键是要选择可靠的方法。主要涉及到如下几个步骤和所用的方法;即自然的接触病原体、评价抗病力和遗传分析,三者构成了研究的关键所在。接触病原体可以通过自然暴露或实验性对照接种。后者的优点是不仅能保证所有的实验动物都接触到病原体。

The Resistance of Chinese Wild Vitis to Uncinula necator and its Inheritance in F_1 Generation

By natural field identification, the resistance of Chinese wild Vitis to Uncinula necator and its inheritance in F1 generation were studied with 35 clones of 9 Chinese wild Vitis species, 171 F1 individuals of 4 inter-species cross between Chinese wild Vitis and Vitis vinifera cultivars, and 16 individuals of selfpollinated Chinese wild Vitis. Results showed that the phenotypes of resistance to Uncinula necator in Chinese wild Vitis and its F1 generation were rich and diverse. Based on the segregation of resisitance to Uncinula necator in the progenies resulted from both interspecific hybridization and self-pollination, of Chinese native wild Vitis species and clones were controlled by polygenes showing dominant independent heredity. Minor resistant genes were also exist in Chinese wild susceptible Vitis species and clones.

Yield Characteristics of a New High-quality Disease-resistant Wheat Variety Chuanmai 618

[Objectives]The paper was to analyze the yield characteristics of a new high-quality disease-resistant wheat variety Chuanmai 618.[Methods]The yield characteristics of Chuanmai 618 were analyzed using the AMMI model and GGE biplot based on data from a 2-year regional test and a 1-year production test.[Results]The analysis of the AMMI model for the 2-year regional test indicated that Chuanmai 618 had a moderate yield and good stability.During the production test,Chuanmai 618 had an average yield of 450.52 kg/666.7 m^(2),an effective spike of 235700 spike/666.7 m^(2),a 1000-seed weight of 47.93 g,and a kernel number per spike of 47.28.The AMMI analysis sequencing graph showed that the varieties were ranked in the following order:Zhongkemai 1816>Chuanmai 618>Shumai 1958>Chuanyu 42>Mianmai 367>Xikemai 5518.According to the GE analysis,Chuanmai 618 had comparative advantages.[Conclusions]The new wheat variety Chuanmai 618 is a high-quality disease-resistant variety with good yield and stability.

10 Cultivars of the Rejuvenation Rose Group

On the basis of six-years’study (1986-1991) in the field of distant crossing, ten rose cultivars-elect of the to be established Rejuvenation Rose Group are recommended here for the first time. These cultivars have performed satisfactory ornamental characteristics and hardiness in Beijing.

Transcriptome analysis of the spleen of heterophils to lymphocytes ratio-selected chickens revealed their mechanism of differential resistance to Salmonella

Salmonella is one of the most common food-borne pathogens and its resistance in chicken can be improved through genetic selection.The heterophils/lymphocytes(H/L)ratio in the blood reflects the immune system status of chicken.We compared the genome data and spleen transcriptomes between the H/L ratio-selected and non-selected chickens,after Salmonella infection,aiming to identify the key genes participating in the antibacterial activity in the spleen.The results revealed that,the selected population had stronger(P<0.05)liver resistance to Salmonella typhimurium(ST)than the non-selected population.In the selected and non-selected lines,the identified differentiation genes encode proteins involved in biological processes or metabolic pathways that included the TGF-beta signaling pathway,FoxO signaling pathway,and Salmonella infection pathway.The results of the analysis of all identified differentially expressed genes(DEGs)of spleen revealed that the G protein-coupled receptor(GPCR)and insulin-like growth factor(IGF-I)signaling pathways were involved in the Salmonella infection pathway.Integrated analysis of DEGs and FST(fixation index),identified candidate genes involved in Salmonella infection pathway,such as GPR39,NTRK2,and ANXA1.The extensive genomic changes highlight the polygenic genetic of the immune response in these chicken populations.Numerous genes related to the immune performance are differentially expressed in the selected and non-selected lines and the selected lines has a higher resistance to Salmonella.

The tissue expression level of BPI gene in piglets from newborn to weaning and its relationship with Gram-negative bacterial infection

The bactericidal/permeability increasing protein (BPI) has an important function of nonspecific killing of Gram-negative bacteria. In this study, qPCR was used to detect the expression of the BPI gene in twelve tissues of Meishan piglets from birth to weaning. BPI gene overexpression, bacterial adhesions count and indirect immunofluorescence were applied to analyze the relationship between BPI gene expression and the infectivity of Escherichia coli and Salmonella. The results showed that the BPI gene was expressed highly in duodenum, jejunum and ileum (fold changes of relative expression levels were more than 10 000, 500 and 200, respectively). The expression of the BPI gene at 35 days of age was significantly higher (P<0.01) than that at all other days. Transcription of the BPI gene was up-regulated 2 401-fold in porcine intestinal epithelial (IPEC-J2) cells that were transfected with the BPI gene overexpression lentivirus (IPEC-J2-BPI), and significantly higher (P<0.01) than that in negative control cells (IPEC-J2-NC). Protein expression levels in IPEC-J2-BPI cells were also increased. When IPEC-J2 cells were incubated with E. coli and Salmonella, respectively, for 2, 4, 6, 8, 10 and 12 h, the number of bacterial adhesions in IPEC-J2-BPI cells was significantly less (P<0.05) than that in IPEC-J2-NC cells. The results of indirect immunofluorescence analysis showed that the number of bacterial adhesions in IPEC-J2-BPI cells was significantly less (P<0.01) than that in IPEC-J2-NC cells. These results demonstrated that the BPI gene might play an important role in regulating weaning stress especially intestinal-mediated immune response. Overexpression of the BPI gene at the cellular level could significantly enhance the anti-bactericidal ability against Gram-negative bacteria such as E. coli and Salmonella. This has important biological significance in piglet resistance to bacterial diarrhea.

Association between microsatellite markers and bovine tuberculosis in Chadian Zebu cattle

Bovine tuberculosis (BTB) is a considerable threat to livestock keepers and public health in many developing and underdeveloped countries. We investigated associations between 20 microsatellite markers and three phenotypes for BTB in a sample of the Chadian cattle population. The phenotypes measured were: 1) single intra-dermal comparative cervical tuberculin test (SICCT) performed on live animals, 2) presence of lesion post-slaughter, 3) a bacteriological tissue culture test for Mycobacterium bovis using the samples with observed lesions and 4) a predicted Bayesian model (BM) estimate of a true BTB disease status using all tested animals. All traits were recorded in binary form and as either 1 = presence or 0 = absence. A total of 224 animals for SICCT, lesion and BM traits and 96 animals with bacteriological culture test were genotyped. Generalised linear models were fitted to the binary BTB phenotypes that consisted of age (covariate), sex (2 levels), breed (2 levels) and markers (alleles: 5 - 14 levels) as explanatory variables and implemented in R using glm with a logit link function. The model was fitted for each marker, separately. Six out of 20 markers tested were significantly associated with at least one trait considered;these were ILSTS005, ILSTS006, TGLA227, BM2113 and CSRM66. Genomic regions around these markers may serve as a basis for further functional investigations. This is the first study to report association of microsatellite markers with bovine tuberculosis traits in African or Chadian cattle population.

A new way of creating new wheat germplasms resistant to wheat diseases

The improvement of wheat cultivar cannot be done without resistant germplasms. Distant hybridization has been a useful way in the creation of new. disease-resistant wheat germplasms. Using distant hybridization, the disease-resistant genes of the near genera of wheat can be transferred to the common wheat. However, the separation generation of distant hybrids is relatively long, and no effective approach has been developed to shorten this generation. It is very difficult to obtain stable wheat lines which have