Necrotrophic oomycetous Pythium myriotylum (Pm) is a major constraint to the productivity of many crops, including the spice crop, ginger. Current disease management practices relying on synthetic agrochemicals pose significant environmental and health hazards. Moreover, the available biopesticides, largely based on Trichoderma and Pseudomonas species, are often ineffective under field conditions. This necessitates the development of alternative strategies based on innate microbes that have co-evolved with the host and developed mechanisms to antagonize Pythium spp. In this context, the present study evaluated the potential of previously isolated endophytes from a wild ginger congener, namely, L1Zzksd8 (Klebsiella spp), ZzER11 (Bacillus amyloliquefaciens), ZzTC6 (Bacillus pumilus) and ZzER62 (Bacillus subtilis), which have proven plant growth promoting effects. The isolates were assessed both individually and in combination through biopriming of ginger rhizomes. The combination ZzER62 + L1Zzksd8 and ZzER62 + ZzTC6 were found to be particularly effective, not only in suppressing soft-rot disease but also in promoting multiple bud sprouting in ginger rhizomes. Among these, biopriming with ZzER62 + L1Zzksd8 combination led to statistically significant increase (p < 0.0001) in key biochemical parameters, including total protein (7.66 ± 0.46 mg/g), total sugars (24.88 ± 0.32 mg/g) and reducing sugars (6.05 ± 0.02 mg/g), indicating enhanced metabolic activity and vigor of the rhizomes. Additionally, the endophyte combination significantly induced (p ≥ 0.0001) the activity of key anti-oxidant enzymes in the primed rhizome, including catalase (0.031 ± 0.005 U/ml), peroxidase (7.56 ± 0.47 U/ml) and superoxide dismutase (56.25 ± 1.85 U/ml). This enzymatic upregulation reflects a primed defense status, contributing to enhanced resilience against soft-rot disease and mitigation of oxidative stress during Pythium invasion. Consequently, biosurfactants (BS) extracted from ZzER62 and L1Zzksd8 were incorporated into talc-based formulations and evaluated for their efficacy in controlling soft-rot disease. The formulations amended with 50% BS remained stable and biologically active for up to 180 days. These formulations effectively inhibited Pm mediated soft-rot disease and promoted bud sprouting, underscoring their dual potential as biocontrol agents and growth-promoting inputs for sustainable ginger cultivation.

Biosurfactant amended talc- based formulation for management of soft-rot disease in ginger caused by necrotrophic Pythium myriotylum

期刊论文
发表日期：

2026年7月31日

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Harsha K,
Aswati Ravindranathan Nair

摘要

Necrotrophic oomycetous Pythium myriotylum (Pm) is a major constraint to the productivity of many crops, including the spice crop, ginger. Current disease management practices relying on synthetic agrochemicals pose significant environmental and health hazards. Moreover, the available biopesticides, largely based on Trichoderma and Pseudomonas species, are often ineffective under field conditions. This necessitates the development of alternative strategies based on innate microbes that have co-evolved with the host and developed mechanisms to antagonize Pythium spp. In this context, the present study evaluated the potential of previously isolated endophytes from a wild ginger congener, namely, L1Zzksd8 (Klebsiella spp), ZzER11 (Bacillus amyloliquefaciens), ZzTC6 (Bacillus pumilus) and ZzER62 (Bacillus subtilis), which have proven plant growth promoting effects. The isolates were assessed both individually and in combination through biopriming of ginger rhizomes. The combination ZzER62 + L1Zzksd8 and ZzER62 + ZzTC6 were found to be particularly effective, not only in suppressing soft-rot disease but also in promoting multiple bud sprouting in ginger rhizomes. Among these, biopriming with ZzER62 + L1Zzksd8 combination led to statistically significant increase (p < 0.0001) in key biochemical parameters, including total protein (7.66 ± 0.46 mg/g), total sugars (24.88 ± 0.32 mg/g) and reducing sugars (6.05 ± 0.02 mg/g), indicating enhanced metabolic activity and vigor of the rhizomes. Additionally, the endophyte combination significantly induced (p ≥ 0.0001) the activity of key anti-oxidant enzymes in the primed rhizome, including catalase (0.031 ± 0.005 U/ml), peroxidase (7.56 ± 0.47 U/ml) and superoxide dismutase (56.25 ± 1.85 U/ml). This enzymatic upregulation reflects a primed defense status, contributing to enhanced resilience against soft-rot disease and mitigation of oxidative stress during Pythium invasion. Consequently, biosurfactants (BS) extracted from ZzER62 and L1Zzksd8 were incorporated into talc-based formulations and evaluated for their efficacy in controlling soft-rot disease. The formulations amended with 50% BS remained stable and biologically active for up to 180 days. These formulations effectively inhibited Pm mediated soft-rot disease and promoted bud sprouting, underscoring their dual potential as biocontrol agents and growth-promoting inputs for sustainable ginger cultivation.