Decreased Root-Knot Nematode Gall Formation in Roots of the Morning Glory Ipomoea tricolor Symbiotic with Ergot Alkaloid-Producing Fungal Periglandula Sp.

Many species of morning glories (Convolvulaceae) form symbioses with seed-transmitted Periglandula fungal endosymbionts, which produce ergot alkaloids and may contribute to defensive mutualism. Allocation of seed-borne ergot alkaloids to various tissues of several Ipomoea species has been demonstrated, including roots of I. tricolor. The goal of this study was to determine if infection of I. tricolor by the Periglandula sp. endosymbiont affects Southern root-knot nematode (Meloidogyne incognita) gall formation and host plant biomass. We hypothesized that I. tricolor plants infected by Periglandula (E+) would develop fewer nematode-induced galls compared to non-symbiotic plants (E-). E+ or E- status of plant lines was confirmed by testing methanol extracts from individual seeds for endosymbiont-produced ergot alkaloids. To test the effects of Periglandula on nematode colonization, E+ and E- I. tricolor seedlings were grown in soil infested with high densities of M. incognita nematodes (N+) or no nematodes (N-) for four weeks in the greenhouse before harvesting. After harvest, nematode colonization of roots was visualized microscopically, and total gall number and plant biomass were quantified. Four ergot alkaloids were detected in roots of E+ plants, but no alkaloids were found in E- plants. Gall formation was reduced by 50% in E+ plants compared to E- plants, independent of root biomass. Both N+ plants and E+ plants had significantly reduced biomass compared to N- and E- plants, respectively. These results demonstrate Periglandula's defensive role against biotic enemies, albeit with a potential trade-off with host plant growth.

Evolution of Spermophagus seed beetles (Coleoptera, Bruchinae, Amblycerini) indicates both synchronous and delayed colonizations of host plants.

Seed beetles are a group of specialized chrysomelid beetles, which are mostly associated with plants of the legume family (Fabaceae). In the legume-feeding species, a marked trend of phylogenetic conservatism of host use has been highlighted by several molecular phylogenetics studies. Yet, little is known about the evolutionary patterns of association of species feeding outside the legume family. Here, we investigate the evolution of host use in Spermophagus, a species-rich seed beetle genus that is specialized on two non-legume host-plant groups: morning glories (Convolvulaceae) and mallows (Malvaceae: Malvoideae). Spermophagus species are widespread in the Old World, especially in the Afrotropical, Indomalaya and Palearctic regions. In this study we rely on eight gene regions to provide the first phylogenetic framework for the genus, along with reconstructions of host use evolution, estimates of divergence times and historical biogeography analyses. Like the legume-feeding species, a marked trend toward conservatism of host use is revealed, with one clade specializing on Convolvulaceae and the other on Malvoideae. Comparisons of plants' and insects' estimates of divergence times yield a contrasted pattern: on one hand a quite congruent temporal framework was recovered for morning-glories and their seed-predators; on the other hand the diversification of Spermophagus species associated with mallows apparently lagged far behind the diversification of their hosts. We hypothesize that this delayed colonization of Malvoideae can be accounted for by the respective biogeographic histories of the two groups.

Development, survival and description of the life stages of Zatrephina lineata (Coleoptera: Chrysomelidae) fed on Ipomoea pes-caprae leaves.

Zatrephina lineata (Coleoptera: Chrysomelidae) is a phytophagous insect, mainly of plants of the genera Ipomoea and Mikania. The objective was to study the development, survival and to describe the life stages of Z. lineata fed on leaves of Ipomoea pes-caprae. Biological observations were made daily with the aid of a stereoscopic microscope and the instars of this insect identified by the exuvia left between one moulting and the next. The duration of development and survival of the egg, larva and pupa stages and the first, second, third, fourth and fifth instars and of the nymph stage of Z. lineata differed, but not between sexes of this insect. The duration of development of Z. lineata was longer in the larval stage and in the fifth instar, and its survival greater in the egg and pupa stages and in the first and fifth instars. Zatrephina lineata eggs, cream-colored, are ellipsoid and deposited in groups on the adaxial surface of older I. pes-caprae leaves. The larvae of this insect go through five instars, with the first three being gregarious with chemo-behavioral defenses. The exarated pupae of Z. lineata, light yellow in color and with an oval shape flattened dorsoventrally, attach to the abaxial surface of the I. pes-caprae leaves. The shape of adults of this insect is oval, straw yellow in color with lighter longitudinal stripes and females are slightly larger than males.

Multiplex PCR for the simultaneous identification and detection of Meloidogyne incognita, M. enterolobii, and M. javanica using DNA extracted directly from individual galls.

Meloidogyne incognita, M. enterolobii, and M. javanica are the most widespread species of root-knot nematodes in South China, affecting many economically important crops, ornamental plants, and fruit trees. In this study, one pair of Meloidogyne universal primers was designed and three pairs of species-specific primers were employed successfully to rapidly detect and identify M. incognita, M. enterolobii, and M. javanica by multiplex polymerase chain reaction (PCR) using DNA extracted from individual galls. Multiplex PCR from all M. incognita, M. enterolobii, and M. javanica isolates generated two fragments of ≈500 and 1,000, 500 and 200, and 500 and 700 bp, respectively. The 500-bp fragment is the internal positive control fragment of rDNA 28S D2/D3 resulting from the use of the universal primers. Other Meloidogyne spp. included in this study generated only one fragment of ≈500 bp in size. Using this approach, M. incognita, M. enterolobii, and M. javanica were identified and detected using DNA extracted directly from individual galls containing the Meloidogyne spp. at various stages of their life cycle. Moreover, the percentage of positive PCR amplification increased with nematode development and detection was usually easy after the late stage of the second-stage juvenile. The protocol was applied to galls from naturally infested roots and the results were found to be fast, sensitive, robust, and accurate. This present study is the first to provide a definitive diagnostic tool for M. incognita, M. enterolobii, and M. javanica using DNA extracted directly from individual galls using a one-step multiplex PCR technique.

Developmental and reproductive response of Brachmia macroscopa (Lepidoptera: Gelechiidae) to three host plants.

The sweet potato leaf folder, Brachmia macroscopa Meyrick (Lepidoptera: Gelechiidae), which is a significant pest of plants in the family Convolvulaceae, is rapidly expanding its range in South China and other subtropical regions. Studies were designed to examine the effects of three different host plants (sweet potato, Ipomoea batatas (L.) Lam.; water spinach, I. aquatica Forsskål; and morning glory, Pharbitis purpurea (L.)) on the development and life table parameters of B. macroscopa under laboratory conditions. We found that the intrinsic rates of increase of B. macroscopa were 0.17 ± 0.004, 0.21 ± 0.005 and 0.16 ± 0.004 on I. batatas, I. aquatica and P. purpurea, respectively. The highest net reproduction rate was 158.06 ± 18.22 per female reared on I. aquatica. The larvae had five instars when reared on I. batatas and I. aquatica, but required six instars on P. purpurea. The mean generation lengths of B. macroscopa ranged from 24.32 ± 0.18 days when reared on I. aquatica to 29.40 ± 0.24 days on P. purpurea. The survival of all stage and fecundity curves was intuitively manipulated using the age-stage-structured and two-sex population life table method, to enable comprehensive descriptions of the stage and population trends of B. macroscopa on the three Convolvulaceae plants. Our results indicated that I. batatas and I. aquatica were more suitable host plants than P. purpurea.

Faecal and protozoan parasite contamination of water spinach (Ipomoea aquatica) cultivated in urban wastewater in Phnom Penh, Cambodia.

OBJECTIVE: To identify the level of contamination with thermotolerant coliforms (ThC), intestinal helminth eggs and protozoan parasites in water spinach (Ipomoea aquatica) cultivated in a wastewater-fed lake in Phnom Penh, Cambodia. METHODS: The investigation was carried out from July 2004 to May 2005 in Boeng Cheung Ek lake, a main recipient of wastewater from the city of Phnom Penh. Water spinach samples were collected near two wastewater entry points in the northern part of the lake and near a wastewater exit point in the southern part of the lake, where water is discharged from the lake into a stream. Water spinach samples were harvested at each of the three locations with and without wastewater contact according to the normal practices of farmers, and analysed for ThC, protozoan parasites (Giardia, Cryptosporidium and Cyclospora), and helminth eggs (Ascaris lumbricoides, Trichuris trichura and hookworm) using standard methods. Wastewater samples were also collected at each of the three locations and analysed for ThC and helminth eggs. RESULTS: High concentrations of ThC (approximately 10(5)-10(7)/g) were found in water spinach samples. ThC mean counts did not differ significantly, neither between sample types at each location, nor between locations. ThC mean concentration of water spinach samples collected in the rainy season of 2005 was higher than that in the dry season of 2004. Protozoan parasites were detected in the samples from all three locations and in water spinach harvested with and without wastewater contact. Giardia spp. were present in 56% (20) of samples with an average cyst concentration of 6.6/g. Mean counts of Giardia were not significantly associated with wastewater contact status of water spinach. Cryptosporidium oocysts were found in 17% (six) of samples with an average concentration of 0.5 oocyst per gram of water spinach. Cyclospora oocysts were detected in 8% (three) of samples. Four (11%) water spinach samples contained helminth eggs (average concentration: 0.1 egg per gram). Water samples contained approximately 10(4)-10(7) ThC per 100 ml and a mean of 27.4 helminth eggs per litre. There was a 2-3 log reduction of ThC between the water samples collected at the wastewater entry and exit point(s) of the lake. CONCLUSIONS: Water spinach cultivated in the lake was highly contaminated with feces, as indicated by high ThC concentrations and the presence of protozoan parasites. A reduction in ThC numbers almost to WHO guideline levels for irrigation water occurred through natural biological and physical processes in the lake, as shown by differences in ThC counts at wastewater entry and exit points.

Foliar damage to parental plants interacts to influence mating success of Ipomoea purpurea.

Studies of how herbivory affects plant fitness often determine whether damage to one parent alters reproductive output (i.e., seed set or paternity) but ignore the possibility that the outcome may be different if both parents were damaged (i.e., the presence of maternal x paternal damage interactions). Using inbred lines of the common morning glory, Ipomoea purpurea, I conducted a series of greenhouse experiments to test whether foliar damage from a generalist insect herbivore, Trichoplusia ni, alters male and female fitness components when neither parent, one parent, or both I. purpurea parents had been damaged. In a single-donor experiment, flowers on both damaged and undamaged maternal plants received pollen from either damaged or undamaged paternal plants. I. purpurea flowers were more likely to be aborted when they received pollen from damaged paternal plants, or when maternal plants were both damaged and grown under low-resource conditions. Foliar damaged plants also produced less seed and pollen than undamaged plants, although seed mass and pollen viability were not affected by damage. In a multiple-donor experiment, flowers on damaged and undamaged maternal plants simultaneously received pollen from damaged and undamaged paternal plants, and F1 seeds were analyzed for paternity. Damaged paternal plants had reduced siring success compared to undamaged paternal plants, and this discrepancy was most pronounced when competition occurred on damaged maternal plants. Thus, damaged maternal plants were more "selective" than undamaged maternal plants. Although previous studies have demonstrated that herbivory can alter fruit and seed production and paternity patterns, this is the first study to show that the magnitude of herbivore damage experienced by both parents can interact to influence maternal and paternal mating success.