Isolates of the Nematophagous Fungus Pochonia chlamydosporia Are Endophytic in Banana Roots and Promote Plant Growth

The biocontrol fungus Pochonia chlamydosporia colonizes banana roots endophytically. Root hairs and root surface were colonized by a stable GFP (green fluorescent protein) transformant of the fungus. Hyphal penetration in root cells was also observed. Spores of P. chlamydosporia 123, significantly increase root and leaf length and weight in banana plantlets (Musa acuminata cv. ‘Dwarf Cavendish’) in growth chamber experiments 30 days post-inoculation. In greenhouse 8-L pot experiments, P. chlamydosporia 123 spore inoculation significantly increases root, corm and leaf length, and leaf weight in banana plants (75 days post-inoculation). Spore inoculation of P. chlamydosporia strains from diverse origin (Pc21, Pc123, Pc399, and Pccat), significantly increase root, corm and leaf length and weight in banana plantlets. Pc21 from Italy was the best colonizer of banana roots. Consequently, this strain significantly increases banana root and leaf length most. Root colonization by P. chlamydosporia was also detected using cultural techniques and qPCR.

Worldwide strains of the nematophagous fungus Pochonia chlamydosporia are endophytic in banana roots and promote plant growth

SUMMARYThe biocontrol fungus, Pochonia chlamydosporia, colonizes endophytically banana roots. Root hairs and root surface were found colonize by the fungus using a stable GFP transformant. Hyphal penetration of root cells was also observed. Spores of P. chlamydosporia 123, significantly increase root and leaf length and weight in banana plantlets (Musa acuminata cv. ‘Dwarf Cavendish’) in growth chamber experiments 30 days post-inoculation (dpi). In greenhouse 8L pot experiments, P. chlamydosporia 123 spore inoculation significantly increases leaf and root length and leaf weight in banana plants (75 dpi). Spore inoculation of P. chlamydosporia strains from worldwide origin (Pc21 Italy, Pc123 Spain, Pc399 China, and Pccat Cuba), significantly increases root, corm and leaf length and weight in banana plantlets. Pc21 was the best colonizer of banana roots. Consequently, this strain significantly increases most banana root and leaf length. Root colonization by P. chlamydosporia was also detected using cultural techniques and qPCR.

The Effect of Scleroderma columnare Inoculum Doses to Enhance Ectomycorrhizal Colonization and Growth of Shorea javanica Seedling

Ectomycorrhiza helped plants to absorb nutrients and water. Shorea javanica belong to Dipterocarpaceae family and highly dependent on ectomycorrhiza to growth. Spore inoculation was one way to inoculate ectomycorrhiza fungi. This study aimed to get the best doses of spore Scleroderma columnare on colonization and enhancing growth of Shorea javanica seedling. This experiment used randomized complete design with 5 treatments and 3 replicates. The treatments were 0, 5, 10, 15, and 20 ml/polybag spore inoculum of S. columnare. Data obtained were analyzed by analysis of variance (anova) and continued with Least Significant Different (LSD). The results showed that added of 10 ml (6,5 x 107) gained higher root colonizatition (%). Dosis of 10 ml (6,5 x 107) and 20 ml (1,3 x 108) spore inoculum were able to improve plant growth on the parameters such as plant height, shoot dry weight, total dry weight, and total leaf area. Keywords: Dose of Inoculum, ectomycorrhiza, Scleroderma columnare, Shorea javanica.

Effects of pH, temperature and light intensity on spore germination and growth analysis of young sporophytes of Polypodium lepidopteris (Pteridophyta, Polypodiaceae)

ABSTRACT Polypodium lepidopteris is a terrestrial fern from coastal vegetation, and is used as medicinal. This work analyzed the effects of pH, temperature and light levels on the spore germination and the relative growth rate (RGR) of young sporophytes. Fertile fronds were collected in Florianópolis, SC, Brazil. The effect of pH (4.0 to 6.7) on spore germinability was observed in a growing room at 25 ± 2ºC (22 mmol m-2s-1) under a 16h photoperiod. No statistical differences between treatments were found. The effect of different temperatures on the germinability was analyzed (20, 25 and 30ºC). The test was carried out in a germination chamber (17 mmol m-2s-1) under a 16h photoperiod. The germination was inhibited at 30ºC. The effect of natural light levels (54, 38, 22 and 8%) was analyzed. The highest germination percentages were verified at 22 and 8% of natural light. The growth analyses show statistical differences in the number of fronds and height of the longest frond between time 1 (283 days of spore inoculation) and time 2 (343 days of spore inoculation). Sporophytes of P. lepidopteris produced 1.33 ± 0.09 fronds per month. The RGR (relative growth rate) was 0.15 ± 0,009 cm cm-1month-1.

Contaminations Occurring in Fungal PCR Assays

Successful in vitro amplification of fungal DNA in clinical specimens has been reported recently. In a collaboration among five European centers, the frequency and risk of contamination due to airborne spore inoculation or carryover contamination in fungal PCR were analyzed. The identities of all contaminants were specified by cycle sequencing and GenBank analysis. Twelve of 150 PCR assays that together included over 2,800 samples were found to be contaminated (3.3% of the negative controls were contaminated during the DNA extraction, and 4.7% of the PCR mixtures were contaminated during the amplification process). Contaminants were specified asAspergillus fumigatus, Saccharomyces cerevisiae, and Acremonium spp. Further analysis showed that commercially available products like zymolyase powder or 10× PCR buffer may contain fungal DNA. In conclusion, the risk of contamination is not higher in fungal PCR assays than in other diagnostic PCR-based assays if general precautions are taken.