Isolation and characterization of toxins from Xenorhabdus nematophilus against Ferrisia virgata (Ckll.) on tuberose, Polianthes tuberosa.

This study was aimed to evaluate the toxins of Xenorhabdus nematophilus bacterial isolate MDUStBa15 isolated from the nematode Steinernema carpocapsae that can parasitize two tailed mealybug Ferrisia virgata which is a new pest on tuberose. Soluble protein and organic fractions were characterized from cell free extract of X. nematophilus. Using SDS PAGE, presence of low molecular weight toxic proteins (12, 42 and 60 kDa) was observed in cell free extracts of X. nematophilus. Among these three proteins, 12 kDa was newly found in this study which showed anti-feedant activity and the maximum of 87.50% and 82.50% mortality of crawlers and adults of F. virgata, respectively at 72 h after treatment. GC-MS analysis of culture filtrates revealed the presence of five major compounds, all are exhibiting insecticidal property. Among several organic fractions, 1, 4 - epoxynaphthalene - 1 (2H) - methanol, 4,5,7-tris (1,1 - dimethylethyl) - 3,4 - dihydro; Pentacosane and Hexacosane were found in this study. Pot culture study revealed that an optimum dose of 5 ml/l of crude toxin caused the maximum mortality in crawlers (100%) and in adults (96.8%) of F. virgata at 72 h after spraying. In a field study application of 5 ml/l crude toxin along with biocontrol agent (Ladybird beetle - Cryptolaemus montrouzieri) registered the 90.55% mortality in crawlers and 73.60% mortality in adults of F. virgata at 7 days after spraying. The present study provides the clear evidence for the toxicity of protein; organic fraction and crude toxin which was obtained from X. nematophilus isolate MDUStBa15 against F. virgata on tuberose both in lab and field conditions. Hence, it can be utilised to manage the F. virgata on tuberose.

Specialized pollination by fungus gnats in the introduced population of Aspidistra elatior.

The monocot genus Aspidistra comprises rhizomatous perennials that are distributed in tropical to warm temperate regions of Asia. Little is known about the pollinators of almost all the species, probably due to the inconspicuous nature of Aspidistra flowers. Nevertheless, the unusual floral morphology suggests biotic pollination, since pollen grains are hidden under each flower's stigma. Aspidistra elatior has been suspected to have a very peculiar pollination ecology. So far, pollination by mollusks, crustaceans, or collembolans has been suspected. However, a recent study showed that A. elatior is mainly pollinated by species of fungus gnats in Kuroshima Island, southern Japan, which is its natural habitat. Here, we investigated the pollination ecology of A. elatior in Shiga Prefecture, central Japan, which is the introduced population, to reveal whether fungus gnats are also the main pollinator in the introduced population. Our study confirmed fungus gnats pollination in the investigated pollination. Furthermore, the main pollinators (i.e., Cordyla sixi and Bradysia sp.) are the same in both Kuroshima and Shiga Prefecture. Therefore, A. elatior mainly depends on a narrow taxonomic group of fungus gnats for pollination. In contrast, we failed to document any terrestrial amphipods visiting the A. elatior flowers, in spite of a relatively high fruit set in natural conditions. This fact will refute the amphipod pollination hypothesis proposed by previous studies. We consider that A. elatior is pollinated by fungus gnats through fungal mimicry, due to its superficial similarity to mushroom fruiting bodies and strong, musky floral scent.

Transcriptome analysis, using RNA-Seq of Lomandra longifolia roots infected with Phytophthora cinnamomi reveals the complexity of the resistance response.

The plant pathogen Phytophthora cinnamon the causal agent of disease in numerous species, is a major threat to natural vegetation and has economic impacts in agriculture. The pathogen principally invades the root system, which, in susceptible species, is rapidly colonised and functionally destroyed. Few species are resistant, however, where resistance is expressed the pathogen is restricted to small, localised lesions. The molecular mechanisms that underpin this response in resistant species are not well understood. Lomandra longifolia, an Australian native species, is highly resistant to P. cinnamomi. In an earlier study, we showed induction of resistance-related components such as callose, lignin and hydrogen peroxide (H2 O2 ) in L. longifolia roots that had been inoculated with P. cinnamomi. Here, in order to further identify, during the very early stages of infection, the molecular components and regulatory networks that may trigger resistance, a comprehensive root transcriptome analysis was performed using next generation sequencing. Overall, 18 cDNA libraries were produced generating 52.8 GB 126 base pair reads, which were de novo assembled into contigs. Differentially expressed genes (DEGs) were identified allowing the identification of infection-responsive candidate genes that were putatively related to resistance, and from this set ten were selected for qRT-PCR to validate the RNA-Seq expression value. Further analysis of individual candidates revealed that many were involved in PAMP-triggered immunity (PTI; pattern recognition receptors, glutathione S-transferase, callose synthases, pathogenesis-related protein-1, mitogen activated protein kinases) and effector-triggered immunity (ETI) (NBS-LRR, signalling genes, transcription factors and anti-pathogenic compound synthase genes). As these candidate genes or mediated components activate different defence signalling systems, they may have potential for investigation of novel approaches to disease control and in transgenic approaches for improvement, in susceptible species, of resistance to P. cinnamomi.

Morphology and life cycle of a new species of Didymium (Myxomycetes) from arid areas of Mexico.

A new species of myxomycete, Didymium umbilicatum, isolated from the bark of Agavaceae, is described from arid zones of Mexico. This species was obtained from moist chamber cultures of Yucca spp. bark, collected in four different years from two states (Puebla and Querétaro) in central Mexico and found in the field from Hidalgo, Oaxaca and Puebla on the dead remains of Agave sp. The new species has small, flat, white sporocarps or short plasmodiocarps, 0.2-1.3 mm diam, and 0.15-0.4 mm tall. They are sessile on a reduced base or have a short, calcareous pale stalk and warted spores, warts fused in an irregular subreticulum by SEM. It is the sixth species of Didymium recently described from arid areas. The stability of the taxonomic characters of the species was confirmed by spore-to-spore culture on agar. Life cycle events are described from germination to sporulation. The morphology of the myxomycete specimens was examined with scanning electron microscopy and light microscopy, and micrographs of relevant details are included.