Cynipid galls on oak leaves are resilient to leaf vein disruption

Journal of Plant Research - Oaks serve as host plants for numerous insects, including those forming galls. Galls induced on oaks are completely dependent on leaf resources. Many other folivores...     

Further studies on the maize and rice leaf galls induced by Cicadulina bipunctella

In the Philippines, plant galls were induced by the feeding of Cicadulina bipunctella (Mats.). Every insect collected in nature, as well as all insects raised on healthy maize, were able to produce leaf galls. Approximately 10 days after exposure to the insects, galls appeared on the next developing young leaf, but not on the leaf that was exposed to the insects. No difference was observed between the effect of feeding by single insects and groups of 10 insects. C. bipunctella-induced galls were compared to similar galls induced by the feeding of C. zeae in Africa, C. pastusae in South America, C. bimaculata in Australia, Dalbulus elimatus in America and Euscelis plebejus in Europe. In addition to experimental findings, worldwide association of leaf galls with feeding of leafhoppers belonging to several related species, favours the view that the galls of maize and rice plants are caused by insect toxins, rather than by plant viruses.

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Zusammenfassung Auf den Philippinen wurden Pflanzengallen durch das Saugen von Cicadulina bipunctella (Mats.) hervorgerufen. Jede dieser im Freien gesammelten Zwergzikaden sowie alle an gesundem Mais gezüchteten Individuen waren fähig, Blattgallen zu erzeugen. Ungefähr 10 Tage nach dem Ansetzen der Zikaden erschienen die Gallen auf dem nächsten sich entwickelnden jungen Blatt, jedoch nicht auf dem Blatt, das den Zikaden ausgesetzt worden war. Es wurde kein Unterschied zwischen der Wirkung des Saugens von einzelnen und Gruppen von 10 Zikaden beobachtet. Die von C. bipunctella hervorgerufenen Gallen wurden mit ähnlichen Gallen verglichen, die durch das Saugen von C. zeae in Afrika, C. pastusae in Südamerika, C. bimaculata in Australien, Dalbulus elimatus in Amerika und Euscelis plebejus in Europa erzeugt werden. In Ergänzung zu den experimentellen Befunden begünstigt die weltweite Verknüpfung von Blattgallen mit dem Saugen von Zwergzikaden, die zu einigen verwandten Arten gehören, die Ansicht, daß die Gallen an Mais-und Reispflanzen eher von Insektentoxinen als von Pflanzenviren hervorgerufen werden.

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An abstract of this paper has been presented at the Annual Meeting of the Eastern Branch, Entomological Society of America, New York City, Nov., 1960.     

A new species in the Mycosphaerellaceae from Cecidomyiidae leaf galls on Avicennia marina in South Africa

Antonie van Leeuwenhoek - During studies to investigate the health of mangrove trees in South Africa, high numbers of Avicennia marina were found with leaf galls caused by unidentified adults and...     

The effect of leaf galls of Cynipidae on accumulation and biosynthesis of plant amines in oak trees

Polyamines (PAs) are involved in plant response to abiotic and biotic stresses, however, their role in biochemical insect-plant interactions is not clear. Therefore, we compared the involvement of polyamines and key enzymes of their biosynthesis in gall formation process. The present study had used galls on oak leaves caused by asexual generation (♀♀) of three Cynipidae species, namely Cynips quercusfolii L., Neuroterus numismalis (Fourc.) and N. quercusbaccarum L., as a model. The obtained results indicate that gall formation on oak leaves affected amine content, but intensity of the changes in their levels were strongly dependent on the insect species. Nevertheless the downward trend was dominant among those changes. Changes in the activity of lysine decarboxylase (LDC), tyrosine decarboxylase (TyDC) and ornithine decarboxylase (ODC) usually corresponded with the direction of changes in polyamine contents. Several cases of divergence between changes in amine levels and the rate of their biosynthesis may suggest the involvement of other regulation mechanisms such as: arginine decarboxylase (ADC) and S-adenosylmethionine decarboxylase (SAMDC) as well as amine oxidases involved in its catabolic pathways. Thus, the future studies on biochemical mechanism of regulation of PAs accumulation during galls formation should be focused on importance of these enzymes.     

The relationship between psyllid leaf galls and redbay (Persea borbonia) fitness traits in sun and shade

Spatial autocorrelation in vegetation has been discussed extensively, but little is yet known about how standard plant sampling methods perform when confronted with varying levels of patchiness. Simulated species maps with a range of total abundance and spatial autocorrelation (patchiness) were sampled using four methods: strip transect, randomly located quadrats, the non-nested multiscale modified Whittaker plot and the nested multiscale North Carolina Vegetation Survey (NCVS) plot. Cover and frequency estimates varied widely within and between methods, especially in the presence of high patchiness and for species with moderate abundances. Transect sampling showed the highest variability, returning estimates of 19–94% cover for a species with an actual cover of 50%. Transect and random methods were likely to miss rare species entirely unless large numbers of quadrats were sampled. NCVS plots produced the most accurate cover estimates because they sampled the largest area. Total species richness calculated using semilog species-area curves was overestimated by transect and random sampling. Both multiscale methods, the modified Whittaker and the NCVS plots, overestimated species richness when patchiness was low, and underestimated it when patchiness was high. There was no clear distinction between the nested NCVS or the non-nested modified Whittaker plot for any of the measures assessed. For all sampling methods, cover and especially frequency estimates were highly variable, and depended on both the level of autocorrelation and the sampling method used. The spatial structure of the vegetation must be considered when choosing field sampling protocols or comparing results between studies that used different methods.     

Lipids of oak galls

The nutrient tissues of oak galls accumulate a great amount of lipids. The neutral lipids (essentially triacylglycerol) are the most abundant storage form but some membrane lipids (mainly phospholipids) also occur. However, the galactolipids are very poorly represented. Among the fatty acids, oleic acid is predominant. These data correlate well with the cytological features of gall nutrient cells.     

奇特的虫瘿

虫瘿作为自然界一种奇特的生物现象 ,主要是由致瘿昆虫通过产卵、取食或分泌化学物质刺激植物体而形成的。该文对虫瘿的致瘿原因和成瘿过程进行了详细描述 ,讨论了它与人类和植物的关系 ,并就其中富含脂肪、蛋白质等化学物质展望了未来人类在医疗、工业、园林等行业对虫瘿的开发和利用。     

Endophytic and epiphytic phyllosphere fungi of Camellia japonica: seasonal and leaf age-dependent variations

Seasonal and leaf age-dependent variations in the endophytic and epiphytic phyllosphere fungal assemblages of Camellia japonica were examined and compared. Live leaves of C. japonica were collected in four seasons (May, Aug, Nov, Feb), and fungi were isolated from healthy-looking leaves of 0, 1, 2 and 3 y old. The infection rate and total number of endophytic fungi increased May-Feb, and species richness of endophytes increased as leaves aged. In contrast the infection rate of epiphytic fungi was 100% for all leaf ages at every sampling date. The total number of epiphytic fungi isolated was greatest in May and lowest in Aug. The species richness of epiphytes did not differ significantly by season or leaf age. Eight fungal species were recorded as major phyllosphere fungi of C. japonica. Seasonal variations were detected for the frequencies of Colletotrichum gloeosporioides, C. acutatum, and epiphytes Pestalotiopsis sp.1, Aureobasidium pullulans, Phoma sp.1 and Ramichloridium sp., whereas the frequency of the endophyte Geniculosporium sp.1 varied with leaf age. The frequency of the epiphyte Cladosporium cladosporioides varied with both season and leaf age.     

Benefits of photosynthesis for insects in galls

Insect-induced plant galls are predominantly reputed to act as strong carbon sinks, although many types of galls contain chlorophyll and have the potential to photosynthesize. We investigated whether the photosynthetic capacity of bud galls induced by a Pteromalid wasp, Trichilogaster acaciaelongifoliae, in Acacia longifolia subsidises carbon budgets or provides O₂ to the larvae while concurrently consuming CO₂ in the dense gall tissue, thereby maintaining (O₂) and (CO₂) within the range of larval tolerance. Low (O₂) (<5?%?v/v) were found within the internal tissues of galls, and these concentrations responded only marginally to light, suggesting that the photosynthetic activity within the gall is inconsequential in the provision of O₂ to the larvae. The metabolic response of larvae to reduced (O₂) and elevated (CO₂) indicated that larvae were tolerant of hypoxia/hypercarbia and also capable of reducing their respiratory rates to cope with hypercarbia. The low mortality of larvae in galls shaded with Al-foil for 20?days showed that photosynthesis was not vital for the survival of the larvae, although growth of shaded galls was substantially reduced. Gas exchange measurements confirmed that, while photosynthesis never fully compensated for the respiratory costs of galls, it contributed substantially to the maintenance and growth, especially of young galls, reducing their impact as carbon sinks on the host. We conclude that, although photosynthesis may contribute to O₂ provision, its main role is to reduce the dependence of the insect-induced gall on the host plant for photosynthates, thereby reducing intra-plant, inter-gall competition and enhancing the probability that each gall will reach maturity.     

Fungal diversity in galls of baldcypress trees

The baldcypress midge (Taxodiomyia cupressi and Taxodiomyia cupressiananassa) forms a gall that originates from leaf tissue. Female insects may inoculate galls with fungi during oviposition, or endophytes from the leaf tissue may grow into the gall interior. We investigated fungal diversity inside of baldcypress galls, comparing the gall communities to leaves and comparing fungal communities in galls that had successful emergence versus no emergence of midges or parasitoids. Galls of midges that successfully emerged were associated with diverse gall fungal communities, some of which were the same as the fungi found in surrounding leaves. Galls with no insect emergence were characterized by relatively low fungal diversity.     

Growth requirements ofArabidopsis thaliana crown galls

Crown galls induced onArabidopsis thaliana plants by octopine or nopaline strains ofAgrobacterium tumefaciens were grownin vitro on different media. Dark growth of all tumor tissues was strictly hormone-dependent. In contrast, hormonal autonomy was observed in the light where crown gall calli readily differentiated into teratomas and (sometimes fertile) plants. Differentiating tissues always grew more vigorously than subtended calli. The growth of transformed calli was stimulated by vitamins and partly inhibited by growth regulators in concentrations used for the maintenance of untransformed calli. Crown gall calli, teratomas and sometimes regenerated plants were shown to express lysopine or nopaline dehydrogenase activities.     

Micropropagation ofActinidia polygama from fruit galls

Callus was induced from the fruit galls of Actinidia polygama on the B5 medium supplemented with NAA, BA and kinetin (1 mg l⁻¹ each). When the callus was subcultured on the same medium 3 times, shoot primordia and adventitious roots appeared on the surface of the callus. Shoots subcultured on growth regulator free MS medium or supplemented with NAA (1 mg l⁻¹) formed roots. Chromosome numbers in the root tip of regenerated plantlets were determined as 2n=58, which was the same as that of the mother plants. This revised version was published online in June 2006 with corrections to the Cover Date.     

虫瘿多样性及其与寄主植物和环境间关系

虫瘿是自然界极常见的生物现象,凝聚着昆虫与植物间显著、复杂而密切的协同关系。本文主要阐述了致瘿昆虫的主要类群及其在植物上的致瘿部位、虫瘿外部形态、虫瘿发育过程、虫瘿内部结构、虫瘿寄主植物多样性以及虫瘿空间分布规律等,探讨了致瘿昆虫和寄主植物间相互关系,以及影响虫瘿空间分布的环境因素等。最后对目前虫瘿生物学存在的问题及以后的研究方向进行了讨论,以期为有害虫瘿的控制和有益虫瘿的开发与利用,以及致瘿昆虫与寄主植物间协同演化关系、致瘿昆虫的致瘿机理等研究奠定一定的理论基础。     

The protein content of tissues in cynipid galls (Hymenoptera: Cynipidae): Similarities between cynipid galls and seeds

Cynipid galls are examples of induced plant development, where the gall inducer is in control of cell differentiation and morphogenesis of a new plant organ. This study concentrates on the tissues of the larval chamber common to all cynipid galls. The protein content of the inner gall tissue was compared to that of non‐gall plant tissues. We investigated three oak and two rose galls and their respective host plants. Total protein signatures of inner gall tissues were different from those of non‐gall plant tissues, and among the five galls. N‐terminal sequences were obtained for two abundant proteins from the inner gall tissues of D. spinosa and A. quercuscalicis, which were common to all galls, at 62 and 43 kDa. Database queries suggest the 62 kDa protein to be homologous to a protein disulphide isomerase (PDI), and the 43 kDa protein to be homologous to NAD‐dependent formate dehydrogenase (FDH). A naturally biotinylated protein was detected at 33 kDa during Western analyses with streptavidin. Western analyses revealed the presence of the biotinylated protein and PDI in the inner gall tissues of all five galls, while FDH was only detected in A. quercuscalicis and A. fecundator. PDI was also common to all non‐gall tissues, while FDH was not detected in non‐gall tissues, and the biotinylated protein was only detected in seeds. The proteins identified in the inner gall tissue suggest that (a) inner gall tissues in some galls are under respiratory stress, and (b) cynipid gall formation might involve the ectopic expression of seed‐specific proteins.     

Apoptosis in yeasts

Although yeasts lack some elements of the complex apoptotic machinery of metazoan cells, recent studies show that many features of apoptosis, including a caspase-like activity, can be induced in these organisms by DNA damage and other apoptotic triggers. These remarkable findings provide a compelling argument for increased efforts to bring the powerful genetic approaches available to yeast researchers more directly to bear on questions related to apoptosis and its induction or inhibition by drugs. Yeasts may provide a particularly useful model for understanding connections between DNA damage, cell cycle regulation and apoptosis. Here we summarize these recent findings and explore their implications, particularly for the development of more effective therapeutic strategies for treating cancer.     

Autolysis in yeasts

The term “autolysis” was introduced into biological literature by SALKOVSKY [1]. Ever since it began to be used to designate self-digestion of cells under the action of their own intracellular enzymes. This definition is sufficiently satisfactory with regard to bacteria, and there are published lots of original and review papers dealing specifically with bacteria. Considerably less material has been accumulated on eukaryotes, apparently due to the absence of the fact of the cell self-digestion in most yeasts.     

Patterns of phenolic compounds in leafy galls of tobacco

The chemical composition of ethanolic and aqueous extracts from leafy galls produced after infection of Nicotiana tabacum L. plants with Rhodococcus fascians was drastically changed compared to uninfected controls. Chlorogenic acid was abundant both in uninfected and infected plants, but caffeic acid and another cinnamoyl analogue were new in leafy galls. The most pronounced product induced in leafy galls was identified as 7-O-methyl-6-O-β-d-glucopyranosyl coumarin (7-methyl esculin). This is the first report of the presence of this coumarin derivative in tobacco. Interestingly, 7-methyl esculin did not accumulate in the presence of avirulent R. fascians strains nor was it found in leafy galls on other plant species. However, it did appear in crown galls induced by Agrobacterium tumefaciens on tobacco plants. Intriguingly, none of the phenolics known to accumulate in Solanaceae under pathogen attack were found in leafy galls. 7-Methyl esculin barely affected growth of R. fascians nor was it catabolized. Microscopical analysis showed that autofluorescent compounds were located mainly in the abundant meristematic regions of the leafy galls. We postulate that 7-methyl esculin might locally influence plant cell division. Received: 6 March 1996 / Accepted: 30 August 1996