Optimisation of indole acetic acid production by Neopestalotiopsis aotearoa endophyte isolated from Thymus vulgaris and its impact on seed germination of Ocimum basilicum.

BACKGROUND: Microbial growth during plant tissue culture is a common problem that causes significant losses in the plant micro-propagation system. Most of these endophytic microbes have the ability to propagate through horizontal and vertical transmission. On the one hand, these microbes provide a rich source of several beneficial metabolites. RESULTS: The present study reports on the isolation of fungal species from different in vitro medicinal plants (i.e., Breynia disticha major, Breynia disticha, Duranta plumieri, Thymus vulgaris, Salvia officinalis, Rosmarinus officinalis, and Ocimum basilicum l) cultures. These species were tested for their indole acetic acid (IAA) production capability. The most effective species for IAA production was that isolated from Thymus vulgaris plant (11.16 µg/mL) followed by that isolated from sweet basil plant (8.78 µg/mL). On screening for maximum IAA productivity, medium, "MOS + tryptophan" was chosen that gave 18.02 µg/mL. The macroscopic, microscopic examination and the 18S rRNA sequence analysis indicated that the isolate that given code T4 was identified as Neopestalotiopsis aotearoa (T4). The production of IAA by N. aotearoa was statistically modeled using the Box-Behnken design and optimized for maximum level, reaching 63.13 µg/mL. Also, IAA extract was administered to sweet basil seeds in vitro to determine its effect on plant growth traits. All concentrations of IAA extract boosted germination parameters as compared to controls, and 100 ppm of IAA extract exhibited a significant growth promotion effect for all seed germination measurements. CONCLUSIONS: The IAA produced from N. aotearoa (T4) demonstrated an essential role in the enhancement of sweet basil (Ocimum basilicum) growth, suggesting that it can be employed to promote the plant development while lowering the deleterious effect of using synthetic compounds in the environment.

The potent effect of selenium nanoparticles: insight into the antifungal activity and preservation of postharvest strawberries from gray mold diseases.

BACKGROUND: Most microorganisms that cause food decay and the lower the shelf life of foods are fungi. Nanotechnologies can combat various diseases and deal with the application of nanomaterial to target cells or tissues. In this study selenium nanoparticles (Se-NPs) were synthesized using ascorbic acid and characterized by ultraviolet-visible spectroscopy, transmission electron microscopy (TEM), X-ray diffraction and zeta potential. The different concentrations of As/Se-NPs were tested against various fungi, including Alternaria linicola, Alternaria padwickii, Botrytis cinerea, Bipolaris sp., Cephalosporium acremonium, Fusarium moniliform and Fusarium semitectum. This study tested the influence of coated As/Se-NPs on healthy strawberry fruits and those infected with Botrytis cinerea during 16 days of storage, with regard to shelf life, decay percentage, weight loss, total titratable acidity percentage, total soluble solids content (TSS) and anthocyanin content. RESULTS: Energy-dispersive X-ray analysis showed only two elements: selenium and oxygen. TEM images showed that the nanoparticles ranged in size between 26 to 39 nm and were rhombohedral in shape. Se-NPs showed antifungal activity against all tested fungi, the most effective being against Botrytis cinerea, Cephalosporium acremonium and Fusarium semitectum. During storage periods of strawberries fruits coated with As/Se-NPs, the shelf life was increased, and the number of decaying fruits was less than in control (uncoated) and coated infected fruits. The decline in weight loss was lower in coated fruits than in control fruits. CONCLUSION: These findings demonstrated that As/Se-NPs could effectively maintain the postharvest quality of strawberries, even when the fruit was infected with B. cinerea. © 2024 Society of Chemical Industry.

Polyphenols-Rich Extract of Calotropis procera Alone and in Combination with Trichoderma Culture Filtrate for Biocontrol of Cantaloupe Wilt and Root Rot Fungi.

Fungal diseases have always been a major problem for cantaloupe crops; however, synthetic fungicides are hazardous to humans and the environment. Consequently, a feasible alternative to fungicides without side effects could be by using bio agents and naturally occurring plants with antibacterial potential. This study has achieved a novel procedure for managing wilt and root rot diseases by potentially using Trichoderma sp. culture filtrates in consortium with plant extract of Calotropis procera, Rhizoctonia solani, Fusarium oxysporum, and Pythium ultimum, which were isolated from infected cantaloupe roots with identified root rot symptoms. The antagonistic activity of four Trichoderma isolates and analysis of antibiotics and filtrate enzymes of the most active Trichoderma isolate were determined as well as phytochemical analysis of C. procera plant extract using HPLC-UV. The obtained results showed that all Trichoderma isolates considerably lowered the radial growth of P. ultimum, R. solani, and F. oxysporum in varying degrees. The scanning electron micrographs illustrate the mycoparasitic nature of Trichoderma sp. on F. oxysporum. The phytochemical analysis of C. procera indicated that phenolic contents were the major compounds found in extracts, such as vanillin (46.79%), chlorogenic acid (30.24%), gallic acid (8.06%), and daidzein (3.45%) but including only a low amount of the flavonoid compounds rutin, naringenin, and hesperetin. The Pot experiment's findings showed that cantaloupe was best protected against wilting and root rot diseases when it was treated with both Trichoderma sp. culture filtrates (10%) and C. procera extract of (15 mg/mL), both alone and in combination. This study demonstrates that the application of bio agent Trichoderma spp. filtrate with C. procera phenol extract appears useful for controlling wilting and root rot disease in cantaloupe. This innovative approach could be used as an alternative to chemical fungicide for the control of wilting and rot root diseases.