Oviposition preferences of Maculinea alcon as influenced by aphid (Aphis gentianae) and fungal (Puccinia gentianae) infestation of larval host plants

Abstract 1. The influence of infestation of the larval host plant Gentiana cruciata on the egg‐laying preferences of the xerophilous ecotype of Alcon Blue butterfly (Maculinea alcon) was studied in a semi‐dry grassland area (Aggtelek Karst Region, Northern Hungary). 2. We examined whether oviposition patterns of females differed when G. cruciata stems were uninfested compared with when they were infested by an aphid (Aphis gentianae) or a rust (Puccinia gentianae) species. 3. Females laid more than 90% of their eggs on fertile, uninfested G. cruciata stems, although these stems comprised only ～ 50% of the total stems available. Stems infested by aphids were similar to uninfested ones in properties that had a strong correlation with egg numbers, and yet there were significantly fewer eggs on infested stems than on intact ones. 4. Females never laid eggs on parts of Gentiana stems infested by aphids, and the presence of Lasius paralienus ants, which have a mutualistic interaction with Aphis gentianae, did not increase the repulsive effect of aphids. Infection of Gentiana by Puccinia did not influence the egg‐laying behaviour of females, even though the flowers and buds of infested stems exhibited a delayed development. 5. Aphid infestation can influence butterfly oviposition patterns through both direct and indirect effects. The presence of aphids directly excluded oviposition, but our data also indicated the possibility of an indirect effect of aphid infestation. Stems that had no aphids at the last egg counting, but were infested prior to it, had significantly fewer eggs than those that were never infested.     

An actin-binding protein, LlLIM1, mediates calcium and hydrogen regulation of actin dynamics in pollen tubes

Actin microfilaments are crucial for polar cell tip growth, and their configurations and dynamics are regulated by the actions of various actin-binding proteins (ABPs). We explored the function of a lily (Lilium longiflorum) pollen-enriched LIM domain-containing protein, LlLIM1, in regulating the actin dynamics in elongating pollen tube. Cytological and biochemical assays verified LlLIM1 functioning as an ABP, promoting filamentous actin (F-actin) bundle assembly and protecting F-actin against latrunculin B-mediated depolymerization. Overexpressed LlLIM1 significantly disturbed pollen tube growth and morphology, with multiple tubes protruding from one pollen grain and coaggregation of FM4-64-labeled vesicles and Golgi apparatuses at the subapex of the tube tip. Moderate expression of LlLIM1 induced an oscillatory formation of asterisk-shaped F-actin aggregates that oscillated with growth period but in different phases at the subapical region. These results suggest that the formation of LlLIM1-mediated overstabilized F-actin bundles interfered with endomembrane trafficking to result in growth retardation. Cosedimentation assays revealed that the binding affinity of LlLIM1 to F-actin was simultaneously regulated by both pH and Ca(2+): LlLIM1 showed a preference for F-actin binding under low pH and low Ca(2+) concentration. The potential functions of LlLIM1 as an ABP sensitive to pH and calcium in integrating endomembrane trafficking, oscillatory pH, and calcium circumstances to regulate tip-focused pollen tube growth are discussed.     

A Lily ASR protein involves abscisic acid signaling and confers drought and salt resistance in Arabidopsis

LLA23, an abscisic acid-, stress-, and ripening-induced protein, was previously isolated from lily (Lilium longiflorum) pollen. The expression of LLA23 is induced under the application of abscisic acid (ABA), NaCl, or dehydration. To provide evidence on the biological role of LLA23 proteins against drought, we used an overexpression approach in Arabidopsis (Arabidopsis thaliana). Constitutive overexpression of LLA23 under the cauliflower mosaic virus 35S promoter confers reduced sensitivity to ABA in Arabidopsis seeds and, consequently, a reduced degree of seed dormancy. Transgenic 35SLLA23 seeds are able to germinate under unfavorable conditions, such as inhibitory concentrations of mannitol and NaCl. At the molecular level, altered expression of ABA/stress-regulated genes was observed. Thus, our results provide strong in vivo evidence that LLA23 mediates stress-responsive ABA signaling. In vegetative tissues, it is intriguing that Arabidopsis 35SLLA23 stomata remain opened upon drought, while transgenic plants have a decreased rate of water loss and exhibit enhanced drought and salt resistance. A dual function of the lily abscisic acid-, stress-, and ripening-induced protein molecule is discussed.     

Auxin Antagonistic Effects of Auxin Precursors of the Substituted Amide Type

Cucumber seeds were germinated in Petri-dishes for 6 days withdifferent doses of a number of N-monosubstituted amide derivativesof some chlorophenoxy-alkane-carboxylic acids. Doses of theamides studied were roughly equivalent to 0.1, 1, 10, 100, and1,000 p.p.m. in water. The gross morphological effects of theamide treatments were studied, both with and without the additionof 1 and 10 p.p.m., respectively, of the corresponding carboxylicacid. The amides studied were the N-methyl-, N-ethyl-, N-propyl-,N-iso-propyl-, N-butyl-, and N-benzyl-amides of 2,4-dichlorophenoxyaceticacid (2,4-D), -(2,4-dichlorophenoxy)-propionic acid (2,4-DP),2,4,5-trichlorophenoxyacetic acid (2,4,5-T), and -(2,4,5-trichlorophenoxy)-propionicacid (2,4,s-TP). Thirteen of the twenty-one amide derivatives studied antagonizedthe auxintype plant-growth-regulating effects of their parentcarboxylic acid. The antagonisms observed involved not onlya decrease in the stimulatory effects of the externally appliedauxin acids (counteractions of the abnormal swellings of differentplant parts), but also reduced significantly their inhibitoryeffects, i.e. the inhibitions of growth in length of the hypocotyland of the roots. Since some auxin-type stimulatory effectswere observed with all of the amides studied, it is suggestedthat the thirteen amide derivatives play a double role as plantgrowth regulators in cucumber tissues: (1) to a certain extentthey are transformed by plant enzymes to the corresponding carboxylicacid, i.e. to auxin; and (2) the amides themselves exert anti-auxineffects.     

Parkin‐independent mitophagy—FKBP8 takes the stage

Although the Parkin/PINK1 pathway has received considerable attention in recent years as a key regulator of mitophagy in mammals, it is important to recognize that multiple mitophagy receptors like BNIP3, NIX, and FUNDC1 exist that can promote the selective clearance of mitochondria in the absence of Parkin. In this issue, Bhujabal et al expand the repertoire of Parkin‐independent mitophagy receptors to include the anti‐apoptotic protein, FKBP8. The authors demonstrate that FKBP8 interacts preferentially with LC3A via its LIR motif to destroy damaged mitochondria. During the process, FKBP8 escapes from the destruction presumably to prevent apoptosis during mitophagy 1 .     

SLDP: a Novel Protein Related to Caleosin Is Associated with the Endosymbiotic Symbiodinium Lipid Droplets from Euphyllia glabrescens

Intracellular lipid droplets (LDs) have been proposed to play a key role in the mutualistic endosymbiosis between reef-building corals and the dinoflagellate endosymbiont Symbiodinium spp. This study investigates and identifies LD proteins in Symbiodinium from Euphyllia glabrescens. Discontinuous Percoll gradient centrifugation was used to separate Symbiodinium cells from E. glabrescens tentacles. Furthermore, staining with a fluorescent probe, Nile red, indicated that lipids accumulated in that freshly isolated Symbiodinium cells and lipid analyses further showed polyunsaturated fatty acids (PUFA) was abundant. The stable LDs were purified from endosymbiotic Symbiodinium cells. The structural integrity of the Symbiodinium LDs was maintained via electronegative repulsion and steric hindrance possibly provided by their surface proteins. Protein extracts from the purified LDs revealed a major protein band with a molecular weight of 20 kDa, which was termed Symbiodinium lipid droplet protein (SLDP). Interestingly, immunological cross-recognition analysis revealed that SLDP was detected strongly by the anti-sesame and anti-cycad caleosin antibodies. It was suggested that the stable Symbiodinium LDs were sheltered by this unique structural protein and was suggested that SLDP might be homologous to caleosin to a certain extent.     

Synthesis of protoporphyrin IX induced by 5-aminolevulinic acid in yeast cells in the presence of 2,2;-dipyridyl

5-Aminolevulinic acid (ALA), a precursor of porphyrin synthesis, increased the production of various porphyrin compounds in Candida guilliermondii cells. Metalloporphyrins and protoporphyrin IX (PPIX) were predominantly accumulated, respectively, at ALA concentrations of 0.2-0.4 mM and at those higher than 1.5 mM. 2,2;-Dipyridyl which complexed with bivalent metals significantly increased the content of endogenous PPIX even at ALA concentrations lower than 0.5 mM. Under these conditions, the yeast sensitivity to photodynamic effect of visible light (400-600 nm) dramatically increased due to photosensitization by endogenous PPIX.     

Influence of Chilling on Electrolyte Permeability, Oxygen Uptake and 2,4-Binitrophenol Stimulated Oxygen Uptake in Leaf Discs of the Thermophilic Cucumis sativus

The effect of chilling was studied in leaf discs from the chilling-sensitive Cucumis sativus L. by measurement of the electrolyte leakage from the discs, by oxygen uptake and by uncoupling of respiration with 2,4 dinitrophenol. Short periods of chilling are characterized by minor significant increases of electrolyte permeability, of respiration and of preserved ability to be uncoupled by 2,4-dinilrophenol. A longer period of chilling resulted in a strongly increased electrolyte permeability, in reduced oxygen uptake and in disappearance of uncoupling by 2,4 dinitrophenol. In general the induced changes in permeability and respiration were reversible within 4 days of chilling, if the discs were placed at 25°C after chilling.