Sand Particle Size and Phosphorus Amount Affect Rhizophagus irregularis Spore Production Using In Vitro Propagated Spore as a Starter Inoculum in Rhizosphere of Maize (Zea mays) Plantlets

Abstract

Microbial inoculants, particularly arbuscular mycorrhizal (AM) fungi, have great potential for sustainable crop management. In this study, monoxenic culture of indigenous R. irregularis was developed and used as a tool to determine the minimum phosphorus (P) level for maximum spore production under the in vitro conditions. This type of starter AM fungal inoculum was then applied to an in vivo substrate-based mass-cultivation system. Spore production, colonization rate, and plant growth were examined in maize (Zea mays L.) plant inoculated with the monoxenic culture of R. irregularis in sand graded by particle size with varying P levels in nutrient treatments. In the in vitro culture, the growth medium supplemented with 20 µM P generated the maximum number of spores (400 spores/mL media) of R. irregularis. In the in vivo system, the highest sporulation (≈500 spores g−1 sand) occurred when we added a half-strength Hoagland solution (20 µM P) in the sand with particle size between 500 µm and 710 µm and omitted P after seven weeks. However, the highest colonization occurred when we added a half-strength Hoagland solution in the sand with particle sizes between 710 µm and 1000 µm and omitted P after seven weeks. This study suggests that substrate particle size and P reduction and regulation might have a strong influence on the maximization of sporulation and colonization of R. irregularis in sand substrate-based culture.

Heat Stress-Mediated Constraints in Maize (Zea mays) Production: Challenges and Solutions

“…Maize ( Zea mays ) is an important cereal crop that belongs to the Poaceae family ( Li et al, 2022 ) and has ensured global food security with a worldwide production ≥1 × 10 9 t (10 12 kg) since 2013 ( Faostat, 2017 ). Maize was initially cultivated in tropical areas under rainfed conditions ( Li J. et al, 2021 ; Maitra et al, 2021 ). However, there is an increased demand for maize due to its utilization of carbohydrates as biomass for ethanol fuel production, leaves and stem as livestock fodder, grains as raw material in the baking industry, and food and feed crop in many countries ( Rooney et al, 2007 ; Parmar et al, 2017 ; Dar et al, 2021 ).…”

A bio-sustainable approach for reducing Eucalyptus tree-caused agricultural ecosystem hazards employing Trichoderma bio-sustained spores and mycorrhizal networks

“…To prepare the inoculum, SI was first grown on M-media ( Maitra et al, 2021 ) in a petri dish, and then it was transferred to the seed culture of Kaefer medium ( Hill and Kafer, 2001 ) by cutting out 8 mm of agar discs. The seed culture was grown for 10 days at 30°C on a rotary shaker in a 500-mL flask with 100 mL of medium (Biobase, China).…”

“…The isolated strains’ D2 LSU rDNA sequences were added to the NCBI GenBank database and given an accession number. The phylogenetic analyses were conducted in MEGA11.0 ( Maitra et al, 2021 ).…”

“…To determine the fraction of root length colonized by Serendipita indica , the sample was neutralized for 5 min at room temperature with a 2% HCl solution and stained for 2 min at 90°C with a 2% trypan blue-lactoglycerol solution dye. The root colonization percentage was calculated using the magnified intersection method ( Maitra et al, 2021 ).…”

Optimization of industrial (3000 L) production of Bacillus subtilis CW-S and its novel application for minituber and industrial-grade potato cultivation

“…After sowing seed in the pot, 2 mL of CW-S was fed through a micropipette for inoculation. Plant development was aided by the application of 2 ml of half-strength Hoagland feeding solution without phosphorus (P) to each pot at three-day intervals 60 . After 35 DAS, ten competitive seedlings were harvested from each treatment for data collection.…”