Performance on different host plants of an alien and an indigenous Bemisia tabaci from China

The capacity of the Middle East‐Asia Minor 1 putative species of the whitefly Bemisia tabaci (Gennadius) species complex, commonly referred to as the ‘B biotype’, to invade has often been linked to its presumed wider host range than the indigenous competitors. To determine whether this alien putative species and the indigenous Asia II 1 whitefly putative species, commonly referred to as the ‘ZHJ2 biotype’, differ in their ability to use different host plants, we compared their development, survival and reproduction on eight crop species/cultivars that are commonly cultivated in Zhejiang, China. Of the eight host plants tested, B performed substantially better than ZHJ2 on squash, tomato and tobacco, B and ZHJ2 preformed equally well on cotton and sweet potato, while ZHJ2 performed better than B on kidney bean and pepper. These results indicate that while B generally has a wider host range than many indigenous B. tabaci, an indigenous B. tabaci can perform as well as or better on some host plants. These results combined with the cropping patterns in Zhejiang suggested that the differential capacity to use various host plants between whitefly species is important in mediating the process of invasion by an alien whitefly species.     

土壤呼吸温度敏感性的影响因素和不确定性

土壤呼吸是陆地生态系统碳循环的重要环节之一, 其对温度升高的敏感程度在很大程度上决定着全球气候变化与碳循环之间的反馈关系。为了深刻理解地下生态过程对气候变化的响应和适应,本文综述了土壤呼吸温度敏感性（Q10）的影响因子及其内在机制,并分析了当前研究存在的不确定性。土壤生物、底物质量和底物供应显著调控着土壤呼吸的Q10值,但研究结论仍然有很大差异。温度和水分等环境因子则通过对土壤生物和底物的影响而作用于土壤呼吸的温度敏感性,一般情况下,随着温度的升高,土壤呼吸的Q10值下降;水分过高或过低时Q10值降低。另外本文从土壤温度测定深度、时空尺度、土壤呼吸不同组分温度敏感性差异、激发效应以及采用方法的不同等几方面分析了温度敏感性研究存在的不确定性。并在此基础上, 指出了未来拟重点加强的研究方向:（1）土壤呼吸不同组分温度敏感性差异的机理;（2）底物质量和底物供应对温度敏感性的交互影响;（3）生物因子对土壤呼吸温度敏感性的影响。     

不同番茄材料对B型烟粉虱个体发育和繁殖能力的影响

以甘蓝寄主上连续繁殖多代后的B型烟粉虱为对象,对其在8种番茄材料(4个栽培番茄、3个多毛番茄和1个醋栗番茄)上的产卵量、体型大小、发育历期、存活率以及第2代成虫的产卵量和寿命等生物学参数进行观察.自然情况下(10:00-14:00)接虫,烟粉虱在多毛番茄LA2329上的平均产卵量显著低于栽培番茄9706上的产卵量(分别为11粒,164粒).羽化后,烟粉虱雌虫在多毛番茄LA1777上的寿命显著低于在栽培番茄Moneymaker上的存活寿命(分别为5d,22d);而羽化后雌虫在LA1777上的平均产卵量显著低于在栽培番茄早粉2号上的产卵量(分别为7粒/头,95粒/头).在其他参数,如体型大小、存活率、发育历期等,没有显著性的变化.结果显示,较多毛番茄而言,栽培番茄是烟粉虱的较好寄主.而且,在评价抗烟粉虱番茄材料时,平均产卵量、羽化后雌虫寿命及产卵量是3个有效的评价参数.     

四川天南星属(天南星科)一新种——川西南星

描述了四川西部天南星属(天南星科)植物一新种,即川西天南星.     

川鄂獐耳细辛一新变型

描述了产于湖北神农架的川鄂獐耳细辛1个新变型―――重瓣川鄂獐耳细辛( Hepatica henryi Steward f. pleniflora X.D.Li et J.Q. Li),与原变型的主要区别为花冠重瓣。     

Rhizosphere priming effect increases the temperature sensitivity of soil organic matter decomposition

The temperature sensitivity of soil organic matter (SOM) decomposition has been a crucial topic in global change research, yet remains highly uncertain. One of the contributing factors to this uncertainty is the lack of understanding about the role of rhizosphere priming effect (RPE) in shaping the temperature sensitivity. Using a novel continuous ¹³C‐labeling method, we investigated the temperature sensitivity of RPE and its impact on the temperature sensitivity of SOM decomposition. We observed an overall positive RPE. The SOM decomposition rates in the planted treatments increased 17–163% above the unplanted treatments in three growth chamber experiments including two plant species, two growth stages, and two warming methods. More importantly, warming by 5 °C increased RPE up to threefold, hence, the overall temperature sensitivity of SOM decomposition was consistently enhanced (Q₁₀ values increased 0.3–0.9) by the presence of active rhizosphere. In addition, the proportional contribution of SOM decomposition to total soil respiration was increased by soil warming, implying a higher temperature sensitivity of SOM decomposition than that of autotrophic respiration. Our results, for the first time, clearly demonstrated that root–soil interactions play a crucial role in shaping the temperature sensitivity of SOM decomposition. Caution is required for interpretation of any previously determined temperature sensitivity of SOM decomposition that omitted rhizosphere effects using either soil incubation or field root‐exclusion. More attention should be paid to RPE in future experimental and modeling studies of SOM decomposition.     

Mapping phosphoproteins in Neisseria meningitidis serogroup A

To investigate the phosphorylation capability of serogroup A Neisseria meningitidis (MenA) and to implement our knowledge in meningococcal biology and in bacterial post-translational modifications, cell extracts were separated by 2-DE and 51 novel phosphoproteins were revealed by the use of the highly specific Ser/Thr/Tyr-phosphorylated proteins staining by Pro-Q Diamond and identified by MALDI-ToF/MS. Our results indicate that phosphorylation in MenA is comparable to that of other bacterial species. A first functional characterization of the identified modified proteins was also given, in order to understand their role in meningococcal physiopathology.     

Insecticide resistance in Bemisia tabaci from Cyprus

Abstract A comprehensive study on the Bemisia tabaci (biotype B) resistance to neonicotinoid insecticides imidacloprid, acetamiprid and thiamethoxam, and pyrethroid bifenthrin was conducted in Cyprus. The resistance level to eight field‐collected B. tabaci populations was investigated. The activities of enzymes involved in metabolic detoxification and the frequencies of pyrethroid and organophosphates target site resistance mutations were determined. Moderate to high levels of resistance were detected for imidacloprid (resistance factor [RF] 77–392) and thiamethoxam (RF 50–164) while low resistance levels were observed for acetamiprid (RF 7–12). Uniform responses by the Cypriot whiteflies could be observed against all neonicotinoid insecticides. No cross‐resistance between the neonicotinoids was detected as well as no association with the activity of the P450 microsomal oxidases. Only imidacloprid resistance correlated with carboxylesterase activity. Low to extremely high resistance was observed for insecticide bifenthrin (RF 49–1 243) which was associated with the frequency of the resistant allele in the sodium channel gene but not with the activity of the detoxification enzymes. Finally, the F331W mutation in the acetylcholinesterase enzyme ace1 gene was fixed in all B. tabaci populations from Cyprus.     

Variation for neutral markers is correlated with variation for quantitative traits in the plant pathogenic fungus Mycosphaerella graminicola

We compared genetic variation and population differentiation at RFLP marker loci with seven quantitative characters including fungicide resistance, temperature sensitivity, pycnidial size, pycnidial density, colony size, percentage of leaves covered by pycnidia (PLACP) and percentage of leaves covered by lesions (PLACL) in Mycosphaerella graminicola populations sampled from four regions. Wide variation in population differentiation was found across the quantitative traits assayed. Fungicide resistance, temperature sensitivity, and PLACP displayed a significantly higher Q(ST) than G(ST), consistent with selection for local adaptation, while pycnidial size, pycnidial density and colony size displayed a lower or significantly lower Q(ST) than G(ST), consistent with constraining selection. There was not a statistical difference between Q(ST) and G(ST) in PLACL. We also found a positive and significant correlation between genetic variation in molecular marker loci and quantitative traits at the multitrait scale, suggesting that estimates of overall genetic variation for quantitative traits in M. graminicola could be derived from analysis of the molecular genetic markers.     

Variation at two flowering time genes within and among populations of Arabidopsis thaliana: comparison with markers and traits

Flowering Locus C (FLC) and Frigida are two interacting genes controlling flowering time variation in Arabidopsis thaliana. Variation at these genes was surveyed in 12 A. thaliana populations sampled in France. These populations were also screened for variation at molecular markers [12 microsatellites and 19 cleaved amplified polymorphic sequence (CAPS) markers] and at seven quantitative traits measured with and without vernalization. Seven populations were highly polymorphic at markers (H(S) = 0.57 at microsatellites, 0.24 at CAPS) and showed heritable variation for bolting time and some other traits. Five populations were genetically fixed or nearly fixed. Q(ST) for bolting time without vernalization was significantly higher than F(ST), suggesting local divergent selection. One of the two haplotype groups at FLC (FLC(A)) was very predominant (frequency of 99%). The first exon of Frigida showed elevated nonsynonymous variation, and nine loss-of-function mutations were found throughout the gene. The association between loss-of-function and earlier bolting was confirmed. Overall, 18 Frigida haplotypes were detected. The pattern of variation at Frigida was largely similar to that found at markers and traits, with the same populations being fixed or highly diverse. Metapopulation dynamics is thus probably the main factor shaping genetic variation in A. thaliana. However, F(ST) for functional (FRI) vs. nonfunctional (FRI(Delta)) haplotypes was significantly higher than F(ST) at markers. This suggested that loss-of-function at Frigida is under local selection for flowering time.