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The fungal entomopathogen Beauveria bassiana could be established as an endophyte within jute (Corchorus capsularis) plant through seed inoculation. The highest colonization was observed in ITCC 6063 followed by ITCC 5562 and ITCC 5408 which are statistically at par (p < 0.05). The lowest apion infestation was observed in ITCC 5408, ITCC 6063, ITCC 4512 and ITCC 4563 which are statistically at par (p < 0.05). Highest apion infestation was observed in case of two non-endophytic isolates ITCC 4644 and ITCC 4925. Transcriptome study showed that a significant number of stem-weevil (Apion corchori) resistant genes involved in biosynthesis of plant volatiles viz., oxidative cleavage of fatty acids, LEGO-like building blocks, salicylic acid activation pathway, methyl jasmonic acid synthesis pathway were activated in ten B. bassiana isolate treated plants. RNA Sequencing was used to identify 1017 DEGs between 'endophyte colonised plant' and 'untreated plant'. 1117 genes were up-regulated and 279 genes were down regulated in treated plant. [ABSTRACT FROM AUTHOR]

The red spider mite, Oligonychus coffeae Nietner (Acari: Tetranychidae), is a prevalent mite pest damages tea crops. The present study evaluated the efficacy of L. alba essential oil against O. coffeae. GC and GC-MS analysis of L. alba essential oil revealed geraniol (52.19%) and neral (34.13%) as major compounds. The L. alba essential oil applied at 1500 ppm exhibited 100% mortality of treated mites 48 h after exposure through fumigant toxicity method, while 99% ovicidal activity of essential oil was achieved at 1000 ppm. Similarly, in fumigant bioassay LC50 value against O. coffeae was 87.75 ppm for geraniol and 103.49 ppm for neral at 72 h after exposure. The findings suggest that L. alba essential oil and its major constituents geraniol and neral could be used as eco-friendly acaricide, and can be incorporated as one of the components in IPM after multi-location field trials. [ABSTRACT FROM AUTHOR]

Ridge gourd (Luffa acutangula) is an herbaceous perennial twining vine cultivated globally as vegetable and medicinal plant. During October to January in 2014 and 2015, 40% powdery mildew disease incidence was observed in different areas of Odisha state, India. The pathogenicity experiments confirmed the powdery mildew disease symptoms on artificially inoculated L. acutangula seedlings. Causal organism was identified as Podosphaera xanthii on the basis of morphological and molecular studies. This is the first report of powdery mildew disease on L. acutangula caused by P. xanthii. [ABSTRACT FROM AUTHOR]

Seedlings of cultivated rice variety ADT43 was investigated after challenging with two different abiotic (drought and salinity) and biotic (sheath blight and bacterial leaf blight pathogens) stresses. Salinity and drought stress reduced the growth of seedlings, mainly the higher conditions (100 mM NaCl and 10 days of drought, respectively). Increased level of MDA content was observed in biotic and abiotic-stress treated seedlings. The highest H2O2content was observed under salinity-stressed seedlings and lower level observed under biotic stress. Superoxide dismutase activity showed a gradual decrease in all stress conditions compared to control. Salinity stress resulted in highest activity of catalase compared to biotic stress. The peroxidase activity of the seedlings was found to be increased under salt and drought stress conditions and the activity decreased under biotic stress. Drought stress resulted in induced expression ofPOC1gene whereas the biotic stress showed lower expression level. Suppression of the rice peroxidase would have been the mechanism of overcoming the intrinsic defence in rice by these pathogens. [ABSTRACT FROM PUBLISHER]

Plant growth-promoting rhizobacterium,Pseudomonas fluorescensstrain BICC602 suppresses root-knot nematode (Meloidogyne incognita) by enhancing defence mechanism leading to induced systemic resistance in cowpea (Vigna unguiculata) cv. L.Walp. and tomato (Solanum lycopersicum) cv. Pusa Ruby. In cowpea, the soil treatment proved more effective than foliar spray on root galling and eggs in roots. However, which factors are necessary in the induction of resistance response in plants against nematodes by BICC602 is not yet known. Salicylic acid (SA) production by some bacteria acts as endogenous signal for the activation of certain plant defence responses. In a split-root trial with tomato as a host plant andM. incognitaas challenging parasite, BICC602 induces systemic resistance in tomato plants. Based on the results, it is assumed thatP. fluorescens-induced resistance againstM. incognitain cowpea and tomato is made either through SA-dependent or SA-independent transduction pathway. [ABSTRACT FROM AUTHOR]

Healthy mulberry roots were inoculated with second stage juveniles of the root-knot nematode, Meloidogyne incognita and the sequential anatomical changes in the root concurrent with the development of the nematode were studied with light and scanning electron microscopes. Visible anatomical changes occurred four weeks post-inoculation when the pear-shaped adult female nematodes appeared in the tissues. The infected roots lost their circular outline and increased in thickness as traumatic parenchyma was induced in the root. The stele was disorganised with reduced and deformed vascular elements. Many giant cells developed in the traumatic tissue, adjacent to the adult females. Eight weeks after the inoculation, cavities developed around the adult females by tissue disintegration, and the galls became discernable on the roots. The number and size of thegalls increased in the next three weeks, corresponding to the development of more traumatic tissues and the enlargement of the adult female nematodes. The majority of the nematodes were settled towards the gall periphery, with their posterior oriented outwards for the release of their eggs into soil by the disintegration of the outer root layers. But many were settled deep inside the gall tissue without a channel to release their eggs to soil. The inner cavities enlarged in large proportions, sometimes occupying the major volume of the gall. The conductive tissues of the root were totally disorganised or were nonexistent. [ABSTRACT FROM AUTHOR]

Plants have evolved several types of sophisticated defence mechanisms to protect themselves from enemies in which the signalling molecules such as salicylic acid (SA), jasmonic acid (JA) and ethylene (ET) often play crucial roles. An experiment was conducted to investigate the water induced stress in young tomato plants (Lycopersicon esculentum var. Pusa Ruby) during water deprivation and after relief from stress in association with salicylic acid. Application of SA or certain analogues such as aspirin induces expression of pathogenesis-related proteins (PR) in plants which serve as molecular markers for the systemic acquired response (SAR). In plants, the production of reactive oxygen species (ROS), such as superoxide radical (O2), hydroxyl radical (OH) and hydrogen peroxide (H2O2), is also common in metabolic and physiological processes. Similar to the defence-regulating compounds such as SA and JA, plant-derived ET is also known to be involved in disease resistance. The role of ROS or ET could be investigated which was carried out in the present study to know the osmotic stress mediated resistance by SA against Meloidogyne incognita in tomato plants. [ABSTRACT FROM AUTHOR]

The predatory mite, N. longispinosus preys up on red spider mite, O. coffeae infesting tea in south India. An attempt has been made to determine the predatory potential, prey stage preference and optimum predator–prey ratio of N. longispinosus under laboratory and green house conditions. When 50 adult female O. coffeae were given, the number of adults reduced by eight days along with an increase in the number of predators. The larvae hatched from the eggs laid by O. coffeae were fed by predatory mite. N. longispinosus preyed up on all life stages with a preference to larvae and nymphs of red spider mite. Predator–prey ratios of 1:33 and 1:50 were effective in lab, and 1:25 was found to be effective in green house. These results revealed that N. longispinosus could be used as a successful biocontrol candidate of O. coffeae in tea through augmentation or mass rearing and field release. [ABSTRACT FROM AUTHOR]

Occurrence of various types of viral symptoms viz. mosaic, mottling, puckering, stunting and filiformy/shoestring was noticed on Elephant foot yam in India. Immunosorbent electron microscopy of infected leaf samples with Potyvirus group-specific antiserum revealed the association of flexuous Potyvirus particles. Infected leaf samples were collected from different locations in Kerala, Orissa and Andhra Pradesh; and total RNA was extracted from infected leaves. One-step reverse transcription polymerase chain reaction assay was carried out using Potyvirus group-specific primers and an amplified product of 327 and 719 bp were obtained. Sequence analysis of nucleic acid and deduced amino acid sequences with the already available Potyvirus sequences in Genbank showed 91% and 97% similarity with Dasheen mosaic virus (DsMV) isolate DeSLK2 (accession Number AJ305434) at nucleic acid and amino acid level respectively. Comparison of 3'UTR region using universal primers MJ1 and M4T also confirmed that the virus under study is DsMV and is closely related to DeSLK2 isolate. This is the first molecular level detection of the virus infecting Amorphophallus paeoniifolius in India. [ABSTRACT FROM AUTHOR]

Development and sporogenesis of Colletotrichum gloeosporioides on castor leaf differed from that on other known host plants. C. gloeosporioides had three kinds of hyphae on castor leaf: primary infection hyphae (PIH), runner hyphae (RH) and secondary infection hyphae (SIH). The PIH originated from conidia, grew on leaf surface and entered the leaf by direct penetration of the cuticle without forming appressoria. The RH were sub-cuticular hyphae, the track of which was traceable by the bulgings on the leaf surface, and the SIH were the hyphae that emerged to leaf surface from RH through the cuticle or stomata. Conidia were initiated as small protrusions along the lengths of RH and SIH that got differentiated into distinct conidia, each born on a short stumpy conidiophore without forming any congregation. The protrusions from RH emerged to the leaf surface by piercing the cuticle, and they developed into distinct conidia on the leaf surface. The conidia developed from RH and SIH were identical in size and shape. Even though conidia were occasionally found emerged through stomata, that appeared to be random than a preferred route for the discharge of conidia. The penetration and sporogenesis of C. gloeosporioides on castor leaf differed from that reported on mulberry leaf. [ABSTRACT FROM AUTHOR]

The infection process of the leaf blight fungus Alternaria ricini was studied on castor leaves using scanning electron microscopy. Conidia germinated 9 h post-inoculation producing one to many germ tubes. The germ tubes were of various lengths, branched or unbranched, and terminated in bulbous appressoria on leaf cuticle, or penetrated the leaf through stomata. Appressoria were not formed where the germ tubes penetrated stomata. As the disease symptom appeared as small spots on leaves 11 days post inoculation, abundant conidia emerged from both surfaces of the leaf through epidermis and through stomatal openings, formed in chains on unbranched conidiophores. Conidiophores were solitary or in small clusters of 2 - 4. The emergence of conidiophores through stomata appeared to be random, as conidiophores pierced guard cells of stomata, where there was no emergence through those stomatal openings. The conidia were cylindrical while young and became bottle-shaped with terminal beaks when matured. Each conidium was born singly on a short unbranched conidiophore, and each conidiophore developed from a cushion-shaped base on the leaf surface. [ABSTRACT FROM AUTHOR]

The pre-penetration and infection process of Colletotrichum dematium on mulberry leaf was investigated by scanning electron microscope. Conidia produced on germination appressoria directly or at the end of short germ tubes. Appressoria were formed mostly over cuticle, but sometimes over stomata also. At 72 h post-inoculation, an extensive network of sub-cuticular runner hyphae (RH) was produced. The RH were traceable by the cuticular bulgings on leaf surface. The RH emerged to leaf surface through ruptured cuticle to form secondary infection hyphae (SIH). The SIH re-entered the leaf tissue by sending penetration branches through stomata. Conidia were formed singly on short conidiophores from the RH and SIH, at short intervals. The conidia developed on RH were exposed to leaf surface through ruptured cuticle. Some times conidia were released through stomata also. The RH and SIH had thick knots from which hyphal branches and conidia were developed. Definite acervuli were not developed. [ABSTRACT FROM AUTHOR]

An extracellular, hydrophilic, thermostable phytotoxin was purified to homogeneity from culture fluids of Sarocladium oryzae and sheath rot infected rice plants. The phytotoxin was purified by solvent extraction, gel filtration on Sephadex G-75 and HPLC. Toxicity was evaluated with detached leaf sheath and electrolyte leakage bioassays. Purified phytotoxin induced visible symptoms of the disease, when applied to rice sheath even at a low concentration of 5 μg. The toxin is a glycoprotein with carbohydrate as major component. The importances of the carbohydrate moiety for toxic activity was indicated by inactivation of toxic compound after periodate oxidation. The toxin caused lesions on a number of other monocots and dicots and proved to be non-host specific. This is the first report of the purification and characterization of S. oryzae toxin from in vitro and in vivo and we propose its name SO-toxin. [ABSTRACT FROM AUTHOR]

The effects of the phyotoxin from the fungal pathogen Rhizoctonia solani, causing sheath blight on the expression of defense-related proteins of rice were investigated. The toxin inactivated by chemical treatment and by the toxin-inactivating enzyme α-glucosidase produced by Trichoderma viride was used in the study along with the active toxin. Toxin inactivated by T. viride α-glucosidase and sodium periodate caused significantly less damage and electrolyte leakage to test plants. The active toxin and the pathogen induced thitinase and β-1,3-glucanase synthesis in rice plants, while the inactivated toxin did not have any effect on the expression of these pathogenesis-related proteins. The toxin was found to suppress the peroxidase activity 72h after inoculation and the inactivated toxin restored the activity as that of untreated plants. There was no remarkable change in phenylalanine ammonia lyase activity in rice sheath treated with both the forms of the toxin. [ABSTRACT FROM AUTHOR]

The surface ultrastructure of the conidial stage and the infection process of Colletotrichum lindemuthianum (Sacc. and Magn.) causing anthracnose disease on mulberry leaves are described by scanning electron microscopy. Unicelled conidium is hyaline, cylindrical or dumbbell-shaped which germinates by producing a single germ tube. The germ tubes usually show response to open stomata by growing towards them and extending away from the closed stomata. By 24h after inoculation, the germ tubes develop secondary lateral branches which enter into stomatal cavities and terminate into specialized intrastomatal infection vesicles. These infection vesicles develop primary infection hyphae which invade the leaf tissues. The disease symptoms become apparent by the 5th day after inoculation when large reddish-brown acervuli develop by rupturing the epidermal layer mostly near the idioblasts on the adaxial leaf surface. Abundant short conidiophores, each with a single conidium on its tip, are observed in the large acervuli. [ABSTRACT FROM AUTHOR]

Deals with a study which examined the life stages of fungivorous insect Illeis indica and its feeding behavior on Phyllactinia corylea borne on infected mulberry leaves. Review of related literature; Materials and methodology used; Results and discussion.