No abstract

Five proline-containing diketopiperazines (Pro-DKPs) produced by antagonistic microorganisms as secondary metabolites were selected and synthesized under laboratory conditions. Out of five synthesized Pro-DKPs, cyclo­(l-Pro-l-Ser) (DKP-6) revealed the best inhibition of fungal pathogens (Fusarium verticillioides and Fusarium fujikuroi) of rice under in vitro conditions with effective doses lower than standard fungicide carbendazim. DKP-6 induced stress on the fungal cell membrane integrity, which was revealed by calcofluor white and propidium iodide assays, endorsed by ultra-microscopic details and soluble protein leakage assays. In vivo seed treatment of infested rice seeds with DKP-6 at 2000 μg/mL for 10 h of seed treatment inflicted best reduction in seed rot and seedling blight with respect to control and carbendazim. Significant enhancement in seedling quality parameters were also observed. The work presented the strong influence of cyclo­(l-Pro-l-Ser) as a mycocidal seed treatment agent better than synthetic toxic fungicides for rice.

BACKGROUND The seed‐borne mycopathogen Fusarium verticilliodes is a serious and deleterious pathogen causing substantial losses of rice seeds and grains. Rice seeds are prone to infestation at all points of the production chain and the fungal pathogen continues dormant devastation even during storage, adversely affecting the seed parameters. Its control is compromised due to the nonavailability of recommended fungicides during storage. Nanotechnological interventions can provide effective and ecofriendly alternative against mycopathogens during resting periods. Herein, the zinc sulfide‐meerschaum nano bio‐matrix (nZnS‐MR) is presented to show this strategy, which worked well against F. verticilliodes when applied on freshly harvested rice seeds during 6 months of storage. RESULTS The healthy, smooth and rounded girths of F. verticilloides mycelium were reduced with loss of turgidity, disrupting the hyphal exterior architecture, during in vitro treatment with nZnS‐MR, endorsed by staining methodology, crystal violet and intracellular soluble protein leakage assays. In vivo application on rice seeds optimized 750 μg g−1 of nano zinc sulfide (nZnS) for 6 months of application during storage with maximum reduction of disease parameters [seedling blight (1.19%) and seed rot (5.43%)] and most augmented quality parameters [maximum germination (94.14%), seedling length (22.50 cm), dry weight (0.121 g) and vigor index (11.37)]. nZnS‐MR acted as a slow release nanoformulation of nZnS for long‐term antifungal activity. CONCLUSION nZnS‐MR is presented as an ecofriendly, biocompatible, bio‐efficient, profertilization, cost‐effective green material for the control of F. verticilliodes with rice seed invigorating effect, describing it as new a nano‐generation material for efficient storage application.

No abstract

No abstract