Beyond occurrence: Body condition and stress hormone as integrative indicators of habitat availability and fragmentation in the common toad

Availability and fragmentation of habitat are today identified as key determinants of population maintenance. Disentangling their relative effects is of crucial importance to adequately manage landscapes. However, the classical use of occurrence or abundance data as proxy to assess the responses of populations could be insufficient to detect less drastic impacts than short-term population extinction. We evaluated the effects of both habitat availability and fragmentation at three spatial scales on both the occurrence and two “physiological state” indicators (body condition and level of stress hormone) reflecting the physical state of common toads (Bufo bufo). Our study showed that occurrence was negatively affected only by habitat availability at the largest spatial scale whereas the both physiological state indicators studied at the population scale are significantly altered by both habitat availability and fragmentation at the finest spatial scale. Results obtained with occurrence and physiological state approaches substantially diverge, which highlights the need to also investigate proximal processes to deeply understand how populations are threatened by landscape modifications. The use of physiological state indicators, particularly of body condition, powerful and easy to obtain, could be particularly relevant to detect early warnings of population decline allowing a management before extinction. Only a complete investigation of the potential impacts of landscape on the different population processes could offer a realistic picture of the requirements of populations to avoid drastic alterations.     

Are rhododendron hybrids distinguishable on the basis of morphology and microsatellite polymorphism?

Sequence Tagged Microsatellite Sites (STMSs) and morphological trait markers were used to evaluate 33 rhododendron germplasm for genetic diversity assessment and discrimination power. The average genetic diversity estimates were 0.724 (morphological traits) and 0.174 (STMSs) marker datasets. The Shannon index was higher for morphological traits (1.797) than STMS (0.302). The correlation coefficients obtained by the Mantel matrix correspondence test, which was used to compare the cophenetic matrices for the two markers, showed that estimated values of relationships given for morphological and STMS were not significantly related (p > 0.05). The dataset from STMS, supported by the total probability of identity (1.13 × 10⁻⁹) and total paternity exclusion probability (0.9999), allowed all accessions to be uniquely identified. In summary, STMS marker proved to be an efficient tool in assessing the genetic variability among old broad leaf rhododendron genotypes. The pattern of variation appeared to be consistent, and it can be used for germplasm conservation and management for restoration of historical genetic resources.     

Within-stem variation in wood properties of triploid hybrids of Populus tomentosa at three clonal trials

To obtain a better understanding of variability in wood properties along the stem in triploid hybrids of Populus tomentosa L., basic wood density (BWD) and fiber traits were measured at four sample heights for each tree sampled from three clonal trials. The BWD showed a similar trend at each site in that density was initially decreased then increased with increasing height position. For fiber traits, the fiber length (FL) decreased linearly with the height of the trunk, whereas fiber width and coarseness changed relatively slightly with increasing height position. In addition, the vertical wood properties distribution patterns were different from clones so that some clones showed more markedly change in height positions than others. The joint analysis indicated significant height position effect for BWD and fiber traits, in accordance with site and clonal effect. Significant site × height interaction was found on wood properties, whereas the significant clone × height interaction was only obtained at fiber width. Moreover, variation in the relationships between FL and BWD or other fiber traits showed no consistent pattern with increasing height position.     

贵州本地山羊STAT5A基因多态性及其与生长性状关联分析

本研究通过探讨STAT5A基因SNP与山羊生长性状关联性,旨在为山羊选种选育提供更好的科学依据。实验以贵州白山羊和贵州黑山羊为研究对象,采用DNA池法及PCR-SSCP技术检测STAT5A基因单核苷酸多态性。结果发现,在贵州白山羊和贵州黑山羊STAT5A基因内含子10均检测到1个SNP位点G127A,表现为3种基因型,分别命名为GG、GA和AA。基因型与生长性状关联分析显示,贵州黑山羊基因型GA个体的胸围和体重指标显著高于基因型GG个体（p〈0.05）,而其余3个指标均差异不显著（p〉0.05）;贵州白山羊基因型GA个体的体斜长、胸围和管围指标显著高于基因型GG个体（p〈0.05）,而其余指标均差异不显著（p〉0.05）。研究结果提示：STAT5A基因可能是影响山羊体重、体斜长、管围和胸围的主效基因或与主效基因连锁,G127A位点可望作为提高山羊个体生长性状的分子遗传标记。     

硝酸镧处理对短穗鱼尾葵幼苗耐寒性的影响

为探明硝酸镧对短穗鱼尾葵(Caryotamitis)耐寒生理指标的影响,用4个不同浓度的硝酸镧溶液(0、100、350、500mg/L)喷施盆栽短穗鱼尾葵叶片,经变温处理后检测各项耐寒指标。结果表明,超氧化物歧化酶(SOD)、过氧化物酶(POD)、丙二醛(MDA)、脯氨酸、可溶性蛋白和叶绿素的含量表现出明显的浓度效应,而且25℃恢复后幼苗叶片的各项耐寒指标的模糊隶属函数值分别为0.41、0.46、0.70、0.50,其中350mg/L硝酸镧溶液处理对提高短穗鱼尾葵幼苗的耐寒性具有显著的效应。     

花椰菜花球和植株性状的遗传与相关分析

利用包括基因与环境互作的加性-显性遗传模型对6个花椰菜品种(系)完全双列杂交试验的2 a观察资料进行花球性状与植株性状的遗传效应与相关分析.结果表明,年份间的环境差异对亲本和F1的表现影响较小;单球重、球径、球高、可溶性固形物含量、蛋白质含量、总糖含量和VC含量等花球性状以加性效应为主,普通狭义遗传率较高(53.37%-74.45%),株高、株幅和叶片数等植株性状以显性效应为主,且具有较大的环境互作效应,互作狭义遗传率较高(11.79%-37.27%);花球性状与植株性状间的各效应协方差分析表明,成对性状间的相关同时受到遗传主效应相关与环境互作相关的影响,相关性质和大小因性状不同而异,在间接选择时可加以利用,有助于对这些性状进行同步改良.     

基于全基因组关联分析挖掘水牛产奶相关基因

【目的】 基于全基因组关联分析筛选影响水牛产奶量和产奶质量的相关基因,并验证这些基因的潜在功能,为加快优质高产水牛品种选育提供理论依据。【方法】 选取70头水牛（36头杂交水牛、18头摩拉水牛和16头尼里—拉菲水牛）进行产奶性状表型值测量,同时提取70头水牛的基因组DNA进行简化基因组重测序,结合水牛产奶性状进行主成分分析和全基因组关联分析,基于筛选到的SNP位点查找候选基因并进行GO功能注释分析和KEGG信号通路富集分析。【结果】 70头水牛均具有完整的表型值,且这些产奶性状间存在极显著相关性（P<0.01）; 70头水牛不存在明显的群体分层,基本上可视为1个群体。在与水牛产奶量关联的12个SNPs附近筛选到9个候选基因,其中CDH8、SLC30A7和FANCC等3个基因是与水牛产奶量相关的关键基因;在与水牛高峰产奶量关联的32个SNPs附近筛选到28个候选基因,Yeats4、SMC6、SUMO1、Grin2a、INO80、GEN1、Exd1、GDPD4、ABCG5、LRRK2、Arx和GRM5等12个基因是与水牛高峰产奶量相关的关键基因;在与水牛乳蛋白率关联的3个SNPs附近筛选到1个候选基因（MID1）,显著富集于GO功能条目和KEGG信号通路上（P<0.05,下同）;在与水牛乳脂率关联的3个SNPs附近筛选到1个候选基因（CNTN5）,显著富集于GO功能条目上;在与水牛乳蛋白含量关联的4个SNPs附近筛选到1个候选基因（FAM160A1）,但该基因并未富集到GO功能条目或KEGG信号通路上;在与水牛乳脂含量关联的7个SNPs附近筛选到6个候选基因,其中CTNNA2、SSBP2和IPOll基因是与水牛乳脂含量相关的关键基因。【结论】 基于全基因组关联分析从70头水牛中挖掘出46个产奶性状候选基因,其中20个是水牛产奶性状的关键基因,因此,生产中可选用这些基因作为新的分子标记资源,加速水牛良种选育。此外,基于全基因组关联分析能高效挖掘出水牛产奶相关基因,为数量性状研究开辟了新方向。