Comparative analysis of the biodiversity of fungal endophytes in insect-induced galls and surrounding foliar tissue

Insect-induced galls are abnormal plant growths that can provide food and shelter to their inhabitants,resulting in stressed plant tissue that may alter the conditions for the colonization or proliferation of endophytic fungi.We investigated the effect gall formation has on fungal endophyte communities and diversity.Using three closely-related gallforming aphid species that specialize on poplars,we characterized fungal endophyte diversity in galls and surrounding petiole and leaf lamina tissue.A total of 516 fungal endophyte samples were isolated from 272 tissue samples(32 leaves,31 petioles,and 209 galls),resulting in 23 distinct morphotypes.Despite sharing a common host plant and often forming spatially contiguous galls,the endophyte profiles within the galls of each aphid species were distinct,not only from the galls of the other species,but also from surrounding plant tissue.These results suggest that insect galls can affect the composition of fungal endophyte species in plant tissues,by altering either the colonization or proliferation of their endophytic mycobiota.Likewise,fungal endophytes may be important in the ecology and evolution of insect galls.

Antibacterial and Antifungal Activity of Organic and Peptidic Extracts of Ecuadorian Endophytic Fungi

Antibacterial and antifungal activities of 32 organic and 14 peptidic extracts obtained from twelve endophytic fungi of the Collection of Endophytes Quito-Catolica were tested against the pathogenic bacteria Staphylococcus aureus, Pseudomonas aeruginosa, Serratia marcescens, Escherichia coli and Salmonella enteritidis, and against the fungal oomycete Pythium ultimum. It was observed that the extracts of Marasmiellus candidus (CEQCA-O1113), Xylaria laevis (CEQCA-O1399), Fusarium solani (CEQCA-O1393), Diaporthe helianthi (CEQCA-O1394) and Xylaria sp. (CEQCA-O1400) partially or totally inhibited the microorganisms tested. The extracts CEQCA-O1399.P1 and CEQCA-O1113.D1 showed fungistatic and fungicidal effects against P. ultimum, respectively. Six extracts strongly inhibited S. aureus, and E. coli was strongly inhibited by the extract CEQCA-O1113.E2. Based on a bioassay-guided approach, the extracts with strong bioactivity in the antibacterial assays by an agar diffusion method were also tested by a disk diffusion method, and the minimal inhibitory concentrations were determined by a microdilution assay. The most bioactive extract, CEQCA-O1113.D1, was also purified by high performance liquid chromatography. The extract recovered its initial bioactivity against S. aureus in two fractions after the purification. Overall, the results of this study highlight the potential of the fungal endophytes as producers of bioactive compounds.

Diversity and endophytic fungal composition in Ananas comosus(L.)Merr.var queen cultivar isolated from three different growing conditions

Present study deals with the isolation of endophytic fungi from leaf and root explants of Ananus comosus var queen from three growing conditions i.e.wild,cultivated as monoculture and cultivated as mixed cropping system with rubber plants.A total of twenty-nine endophytic fungal strains along with two nonsporulating forms were isolated from the host plant from three experimental plots.The maximum numbers of fungal strains were found belong to family Aspergillaceae and order Eurotiales.The highest rates of colonization and isolation(p<0.05)of endophytic fungi have been reported in wild foliar explants(95.53±0.53)and monoculture(1.02±0.01),respectively.The highest relative frequency was observed among isolated fungal strains in the case of Lasiodiplodia theobromae isolated from the leaf and root of wild(26.22%)and monoculture(29.62%)explants.In L.theobromae and Aspergillus flavus,isolated from the leaf and roots of wild(21.66%)and monoculture(14.66%)explants showed the highest colonization frequency.Current findings showed that the distribution of fungal endophytes and their relative frequency in host plants vary in three different growing conditions.

Elicitation on Artemisinin Biosynthesis in Artemisia annua Hairy Roots by the Oligosaccharide Extract from the Endophytic Colletotrichum sp. B501

The oligosaccharide elicitor from the mycelial wall of an endophytic Colletotrichum sp. B501 promoted the production of artemisinin in Artemisia annua L. hairy root culture. When hairy roots of 22-day-old cultures (later growth phase) were exposed to the elicitor (20 mg/L) for 4 d, the maximum content of artemisinin reached 1.15 mg/g, a 64.29% increment over the control. The electron X-ray microanalysis disclosed the rapid accumulation of Ca 2+ in the elicited cortical cells of hairy root. The electronic microscope observation revealed the high electron density area in vacuole of elicited cells. During the first day of elicitation the peroxidase activity of hairy roots was improved sharply. Some cellular morphological changes including cell shrinkage, condensation of cytoplasm and nuclear fragmentation, coincident with the appearance of DNA ladders, were observed after the third day of elicitation. It was suggested that the oligosaccharide elicitor triggered the programmed cell death, which may provide the substance or chemical signal for artemisinin biosynthesis.

Antibacterial activities of mangrove leaf endophytic fungi from Luzon Island,Philippines

Fungi associated with mangroves are untapped sources of bioactive secondary metabolites.In this study,628 mangrove leaf endophytic fungi(MLEF)were recorded from 19 mangrove hosts collected from the provinces of Zambales,Batangas,Cavite,and Quezon in Luzon Island,Philippines.The MLEF morphospecies were identified as belonging to the genera Aspergillus,Cladosporium,Colletotrichum,Fusarium,Nigrospora,Penicillium,Pestalotiopsis,Phialophora,and Trichoderma.Screening revealed that the MLEF crude culture extracts were promisingly potent against the gram-positive bacteria Staphylococcus aureus and Micrococcus luteus(ZOI>19 mm)with no or partial activity against the gram-negative bacteria Klebsiella oxytoca and Pseudomonas aeruginosa.Our findings showed that mangrove leaf endophytic fungi are potential sources of bioactive compounds.

Diversity of endophytic phosphate solubilising fungi associated with Pomatocalpa decipiens(Lindl.)J.J.Smith-an endangered orchid in Barbara forest of Odisha,India

Investigations were done to obtain potential phosphate solubilising strains from endophytic mycoflora isolated from the orchid,Pomatocalpa decipiens.928 endophytic phosphate solubilising fungal isolates were obtained from 2400 leaf segments(0.38%recovery)from rare epiphytic orchid Pomatocalpa decipiens present in the Barbara hills of Odisha(India).A number of isolates belonged to different genera such as Paecilomyces,Curvularia,Aspergillus,Cladosporium,Penicillium,Colletotrichum,while others,which were unidentified were classified as mycelia sterilia.Root sampling done from 25 different sites resulted in isolation of 20 endophytic phosphate solubilising fungal isolates from 300 segments(0.1%recovery).Aspergillus,Paecilomyces,Fusarium,Penicillium,and mycelia sterilia were mostly obtained.The qualitative and quantitative assessments of Phosphate(P)solubilisation were performed using TCP and Rock phosphate as P source for those strains.Aspergillus niger(leaf isolate)showed a maximum of 33.2 and 22.7%solubilisation in presence of TCP and Rock phosphate respectively whereas Aspergillus niger(Root isolate)showed a maximum of about 23.9%and 36.2%solubilisation in presence of TCP and Rock phosphate respectively.

Endophytes from medicinal plants and their potential for producing indole acetic acid, improving seed germination and mitigating oxidative stress

Medicinal plants have been used by marginal communities to treat various ailments. However, the potential of endophytes within these bio-prospective medicinal plants remains unknown. The present study elucidates the endophytic diversity of medicinal plants（Caralluma acutangula, Rhazya stricta, and Moringa peregrina） and the endophyte role in seed growth and oxidative stress. Various organs of medicinal plants yielded ten endophytes, which were identified as Phoma sp.（6 isolates）, Alternaria sp.（2）, Bipolaris sp.（1）, and Cladosporium sp.（1） based on 18 S rD NA sequencing and phylogenetic analysis. The culture filtrates（CFs; 25%, 50%, and 100% concentrations） from these endophytes were tested against the growth of normal and dwarf mutant rice lines. Endophytic CF exhibited dose-dependent growth stimulation and suppression effects. CF（100%） of Phoma sp. significantly increased rice seed germination and growth compared to controls and other endophytes. This growth-promoting effect was due to the presence of indole acetic acid in endophytic CF. The gas chromatography/mass spectrometry（GC/MS） analysis showed the highest indole acetic acid content（（54.31±0.21） μmol/L） in Bipolaris sp. In addition, the isolate of Bipolaris sp. exhibited significantly higher radical scavenging and anti-lipid peroxidation activity than the other isolates. Bipolaris sp. and Phoma sp. also exhibited significantly higher flavonoid and phenolic contents. The medicinal plants exhibited the presence of bio-prospective endophytic strains, which could be used for the improvement of crop growth and the mitigation of oxidative stresses.

Fungal endophyte mediated occurrence of seminiferous and pseudoviviparous panicles in Festuca rubra

Fungal endophytes are suggested to manipulate host grass reproduction.Using different grass-endophyte combinations in a four year common garden experiment,we show that endophyte can retain control over the reproductive functions of the host.Plants were collected as seeds from two different environments,meadows and riverbanks.Natural endophyte infection(E+)increased reproductive effort of plants;13 and 15%higher proportion of E+plants produced panicles compared to naturally uninfected(E-)and manipulatively endophyte-infected(ME+)plants,respectively.Meadoworigin E+plants produced also higher number of panicles compared to E-in the last two years,and both meadow-and riverbank-origin ME+plants produced higher number of panicles compared to ME-plants in most of the years.Pseudovivipary was recorded in 5%of the plants each year.Pollen limitation appears not to induce pseudovivipary.Both E+and ME+plants produced higher number of seminiferous panicles compared to E-and ME-plants.The higher proportion of pseudoviviparism in ME+plants compared to E+,Eand ME-plants from meadows suggests specific genotypegenotype cross-talk between endophyte and grass.Pseudovivipary was affected by year and primarily explained by plant reproductive effort since most vigorous plants produced more pseudoviviparous panicles.We propose that endophytes can promote host grass reproduction in a habitatspecific manner and depending on genetic compatibility between partners.However,reproductive behavior depended on maternal habitat and the annual environmental conditions highlighting the importance of long-term experiments to estimate the effects of endophytes on host plant ecology.

Effects of Epichloë endophyte on antioxidant enzymes activities, photosynthesis and growth of three ecotypes of Elymus dahuricus

Fungal endophytes of some cultivated grasses can increase plant performance and competitive abilities,especially under stress. Far less is known about the influence of Epichlo? infections in wild populations of wild grasses. In this study, plants of three Elymus dahuricus ecotypes(WLS, QY and WTS) either infected with Epichlo? endophyte(E+) or uninfected(E–) were grown in the field. The activities of the antioxidant enzymes ascorbate peroxidase, catalase, peroxidase and superoxide dismutase, and concentrations of H_2O_2 and malondialdehyde were examined in the leaves of E+ and E– plants. We also determined photosynthesis parameters,leaf blade and sheath carbohydrate concentration and plant growth parameters of both E+ and E– plants. E+ plants from the WLS and QY populations had significantly higher antioxidant enzyme activities and photosynthetic capability(P < 0.05), superior growth characteristics including more abundant carbohydrate concentration than E– plants. In contrast, in plants from the WTS population,the endophyte had no significant effect on reactive oxygen species scavenging capability and growth performance(P > 0.05), and even displayed some negative effects on plant photosynthetic capability. Thus, endophyte infection significantly affected E. dahuricus antioxidant enzyme activities(P < 0.05), photosynthesis and growth capability,although, the effects varied with plant ecotypes.