Quinoa (Chenopodium quinoa Willd.) is a nutritionally valuable pseudo-cereal with growing cultivation potential in Bangladesh; however, its productivity is increasingly constrained by foliar diseases, particularly leaf spot. During field surveys at Sher-e-Bangla Agricultural University, Dhaka, quinoa plants exhibiting typical leaf spot symptoms were observed. The present study aimed to identify and characterize the causal agent using an integrated morphological, molecular, phylogenetic, and pathogenicity-based approach. A fungal isolate (SMM-CaQSAU-1) was consistently recovered from infected leaves. Morphological characterization on potato dextrose agar revealed grey to black colonies with abundant aerial mycelia and conidia that were ellipsoidal to curved, dark brown, thick-walled, measuring 18–22 × 8–12 µm. Molecular identification based on BLAST analysis showed that the isolate shared 91.70% sequence similarity in the internal transcribed spacer (ITS) region and 98.39% similarity in the large subunit (LSU) rRNA region with the Curvularia alcornii reference strain MFLUCC 10–0703. Phylogenetic analysis using concatenated ITS and LSU sequences placed the isolate within a well-supported C. alcornii clade, distinct from other Curvularia species. Pathogenicity tests on detached leaves and intact quinoa plants reproduced characteristic leaf spot symptoms within 3–5 days after inoculation, and the pathogen was successfully re-isolated, fulfilling Koch’s postulates. To our knowledge, this study represents the first report in Bangladesh of C. alcornii causing leaf spot disease in quinoa. The findings provide critical baseline information for accurate disease diagnosis and highlight a potential emerging threat to quinoa cultivation in Bangladesh, underscoring the need for surveillance, resistance screening, and integrated disease management strategies.
Amit Hasan, Bilkis Nahar, Bodrun Nessa Shompa et al.· PLoS ONE· 0 citations
Enhanced soil salinity is a major constraint to rice production in the coastal regions of Bangladesh. Salinity stress impairs nutrient uptake and induces ionic toxicity and osmotic stress, while excessive use of chemical fertilizers degrades soil health and causes environmental pollution. A novel salt-tolerant endophytic fungus, Aspergillus welwitschiae Ocstreb1, isolated from the halophytic wild rice Oryza coarctata, exhibited multiple plant growth–promoting traits under both non-saline and 900 mM salt-stress conditions in vitro. These findings suggest that Ocstreb1-based biofertilizer could serve as an eco-friendly and cost-effective alternative to enhance rice productivity under saline conditions. In this experiment, the biofertilizer was prepared using fungal spores produced on wheat bran and subsequently mixed with talcum powder as a carrier. Field trials were conducted following a randomized complete block design (RCBD), incorporating different levels of chemical fertilizer application (0%, 80%, and 100% of the BRRI-recommended NPKSZn rates) in both biofertilizer-treated and untreated plants. Compared with the 100% chemical fertilizer treatment, the combined application of biofertilizer and 80% chemical fertilizer resulted in a comparable yield in Barguna and increased yield of 196.6 kg ha⁻¹ in Satkhira. Profitability analysis showed that this treatment provided an additional economic benefit of USD 48–68 ha⁻¹ over the 100% chemical fertilizer treatment. Moreover, fumonisin B1 levels in grains from biofertilizer-treated plants were negligible. In conclusion, commercial production of this biofertilizer will pave the way for enhancing rice yield with less use of chemical fertilizer while promoting sustainable agricultural practice particularly in areas affected by salinity stress.
Amit Chowdhury, J. Bhattacharya, Md. Iyasir Arafat et al.· Discover Agriculture· 0 citations