A multiplex set of microsatellite markers for the scarlet rosefinch (Carpodacus erythrinus)

Cardueline finches have become important models in studies of sexual selection and evolution of carotenoid‐based ornamentation. Here, we describe eight new polymorphic microsatellites isolated from the Scarlet rosefinch (Carpodacus erythrinus) and four from the House finch (Carpodacus mexicanus). Together with the cross‐species amplification of additional loci, originally published for two species of songbirds, we optimized a multiplex panel for C. erythrinus allowing genotyping of 22 polymorphic loci. Number of alleles and heterozygosity per locus in a sample of 34 individuals ranged from three to 38 and from 0.27 to 0.94, respectively.     

The Light Quanta Modulated Physiological Response of Brassica Juncea Seedlings Subjected to Ni(II) Stress

This work is a study of the inter‐relationship between parameters that principally affect the metal up‐take in the plant. The relationships between the concentration of metal in the growth medium, C_s, the concentration of metal absorbed by the plant, C_p, and the total biomass achieved, M, all of which are factors relevant to the efficiency of phytoremediation of the plant, have been investigated via the macro‐physiological response of Brassica juncea seedlings to Ni(II) stress. The factorial growth experiments treated the Ni(II) concentration in the agar gel and the diurnal light quanta (DLQ) as independently variable parameters. Observations included the evidence of light enhancement of Ni toxicity at the root as well as at the whole plant level, the shoot mass index as a possible indicator of shoot metal sequestration in B. juncea, the logarithmic variation of C_p with C_s and the power‐law dependence of M on C_p. The sum total of these observations indicates that for the metal accumulator B. juncea with regard to its capacity to accumulate Ni, the overall metabolic nature of the plant is important – neither rapid biomass increase nor a high metal concentration capability favor the removal of high metal mass from the medium, but rather the plant with the moderate photosynthetically driven biomass growth and moderate metal concentrations demonstrated the ability to remove the maximum mass of metal from the medium. The implications of these observations in the context of the perceived need in phytoremediation engineering to maximize C_p and M simultaneously in the same plant, are discussed.     

Evidence for the sucrose-binding protein role in carbohydrate metabolism and transport at early developmental stage

Despite the large amount of data regarding sucrose-binding proteins (SBP), their functions remain largely unknown and controversial. In this investigation we performed a detailed temporal and spatial characterization of the phenotypes related to photosynthesis, sucrose exudation and carbohydrate metabolism in SBP antisense plants to gain insights into the physiological role of SBP. Significant reductions in net photosynthesis and in stomatal conductance were observed in the SBP antisense lines but were restricted to the vegetative phase, and persisted during a daily time course at this phase. Photosynthesis was saturated at a substantially lower irradiance in source leaves of the antisense lines, suggesting that light utilization is decreased in these plants. A slight reduction in soluble sugars was observed throughout the development of source leaves, partially overlapping a decrease in sucrose synthase activity (EC 2.4.1.13); whereas a transient increase in starch and adinosine diphosphate (ADP)-glucose pyrophosphorylase activity (EC 2.7.7.27) as well as decreased leaf sucrose exudation were detected in the beginning of the vegetative phase. These changes in source leaves were accompanied by reductions in sucrose and starch in sink leaves, hexoses and sucrose in roots and hexoses in shoot apex, which were observed before the occurrence of a significant reduction in height and in leaf number in the transgenic lines. These alterations in growth parameters did not persist throughout the development, but were associated with a delay in flowering time and leaf senescence in the SBP antisense lines. A likely involvement of SBP in sink strength is discussed.     

Seasonal plant water uptake patterns in the saline southeast Everglades ecotone

The purpose of this study was to determine the seasonal water use patterns of dominant macrophytes coexisting in the coastal Everglades ecotone. We measured the stable isotope signatures in plant xylem water of Rhizophora mangle, Cladium jamaicense, and Sesuvium portulacastrum during the dry (DS) and wet (WS) seasons in the estuarine ecotone along Taylor River in Everglades National Park, FL, USA. Shallow soilwater and deeper groundwater salinity was also measured to extrapolate the salinity encountered by plants at their rooting zone. Average soil water oxygen isotope ratios (δ ¹⁸O) was enriched (4.8 ± 0.2‰) in the DS relative to the WS (0.0 ± 0.1‰), but groundwater δ ¹⁸O remained constant between seasons (DS: 2.2 ± 0.4‰; WS: 2.1 ± 0.1‰). There was an inversion in interstitial salinity patterns across the soil profile between seasons. In the DS, shallow water was euhaline [i.e., 43 practical salinity units (PSU)] while groundwater was less saline (18 PSU). In the WS, however, shallow water was fresh (i.e., 0 PSU) but groundwater remained brackish (14 PSU). All plants utilized 100% (shallow) freshwater during the WS, but in the DS R. mangle switched to a soil–groundwater mix (δ 55% groundwater) while C. jamaicense and S. portulacastrum continued to use euhaline shallow water. In the DS, based on δ ¹⁸O data, the roots of R. mangle roots were exposed to salinities of 25.4 ± 1.4 PSU, less saline than either C. jamaicense (39.1 ± 2.2 PSU) or S. portulacastrum (38.6 ± 2.5 PSU). Although the salinity tolerance of C. jamaicense is not known, it is unlikely that long-term exposure to high salinity is conducive to the persistence of this freshwater marsh sedge. This study increases our ecological understanding of how water uptake patterns of individual plants can contribute to ecosystem levels changes, not only in the southeast saline Everglades, but also in estuaries in general in response to global sea level rise and human-induced changes in freshwater flows.     

Spawning activity of the four major Chinese carps in the middle mainstream of the Yangtze River,during the Three Gorges Reservoir operation period,China

River flow alterations caused by dams have introduced many ecological problems, in particular a decline in aquatic species such as fishes. One compensatory measure is to create a hydrological process similar to the natural state with regard to the survival requirements of the fish. In recent years, the Three Gorges Reservoir (TGR) has introduced man‐made flood by ecological operation experiments to facilitate spawning of the four major Chinese carps in the Yangtze River, China. To investigate the fish spawning activities and their responses to the TGR operation, eggs from the four major Chinese carps were sampled using conical drift nets in the middle mainstream of the Yangtze River, May to July in 2012 and 2013. Spawning timing, location, and scale of the four carps were studied and compared between the 2 years; key hydrological and environmental factors associated with spawning were determined by principal component analysis and stepwise regression analysis. Two factors were significantly positive when correlated with egg abundance: one was increasing rate of the river flow (flood amplitude), and the other was river transparency; only one factor, starting of the river flow (flooding occasions), was significantly and negatively correlated with the time of spawning. Comparison of egg abundance in one flood pulse response to different operation rules showed that flooding made by an ecological operation induced a larger scale of spawning than a conventional operation. The study implied that suitable flood conditions could produce a successful spawning event, and that the occasion and pattern of the flood process might result in different responses in fish spawning. Further research is required to develop more scientific monitoring designs in order to obtain accurate field data for both biotic and abiotic factors, and explore new research methods for egg abundance estimations combined with particle experiment and hydrodynamic modeling. This work is fundamental to improve the strategic decisions on reservoir operation and river management.     

The activation of the atypical PKC zeta in light‐induced retinal degeneration and its involvement in L‐DNase II control

Light‐induced retinal degeneration is characterized by photoreceptor cell death. Many studies showed that photoreceptor demise is caspase‐independent. In our laboratory we showed that leucocyte elastase inhibitor/LEI‐derived DNase II (LEI/L‐DNase II), a caspase‐independent apoptotic pathway, is responsible for photoreceptor death. In this work, we investigated the activation of a pro‐survival kinase, the protein kinase C (PKC) zeta. We show that light exposure induced PKC zeta activation. PKC zeta interacts with LEI/L‐DNase II and controls its DNase activity by impairing its nuclear translocation. These results highlight the role of PKC zeta in retinal physiology and show that this kinase can control caspase‐independent pathways.     

The AvrE superfamily: ancestral type III effectors involved in suppression of pathogen‐associated molecular pattern‐triggered immunity

The AvrE superfamily of type III effectors (T3Es) is widespread among type III‐dependent phytobacteria and plays a crucial role during bacterial pathogenesis. Members of the AvrE superfamily are vertically inherited core effectors, indicating an ancestral acquisition of these effectors in bacterial plant pathogens. AvrE‐T3Es contribute significantly to virulence by suppressing pathogen‐associated molecular pattern (PAMP)‐triggered immunity. They inhibit salicylic acid‐mediated plant defences, interfere with vesicular trafficking and promote bacterial growth in planta. AvrE‐T3Es elicit cell death in both host and non‐host plants independent of any known plant resistance protein, suggesting an original interaction with the plant immune system. Recent studies in yeast have indicated that they activate protein phosphatase 2A and inhibit serine palmitoyl transferase, the first enzyme of the sphingolipid biosynthesis pathway. In this review, we describe the current picture that has emerged from studies of the different members of this fascinating large family.