Piriformospora indica, a Cultivable Endophyte for Growth Promotion and Disease Management in Taro ( Colocasia esculenta (L.)

Abstract

Taro leaf blight caused byPhytophthora colocasiaeis the most destructive disease which causesabout 50% yield loss. Use of resistant varieties, adopting cultural methods, application of fungicidesand use of biological agents are the prevailing management practices against leaf blight.Piriformosporaindicais an endophytic mycorrhiza like fungus which has shown pronounced growth promotional anddisease suppressing activities in many crops. A study was conducted in ICAR- CTCRI, Sreekariyam toexplore the potential ofP. indicacolonization in taro to promote growth and leaf blight resistance. Thecolonization ability ofP. indicain taro varieties Sree Kiran and Muktakeshi was studied by Trypan bluestaining, chitin specific WGA-AF 488 staining and also by amplifying species specific TEF1 gene. Anincrease in all the growth parameters was noted in the colonized plants compared to control plants inpot culture experiment. There was a substantial decrease in the disease incidence in colonized plantsof both the varieties. During different stages of infection, about 57.6, 50.7 and 84.3% decrease inPDI was observed inP. indicacolonized Sree Kiran and in case of Muktakeshi, reduction was 39.9,56.2 and 72.5% over control. Increase in the activity of defense enzymes like chitinase,β-1, 3glucanase and total phenol was observed inP. indicacolonized plants compared to un-inoculatedduring initial hours of infection. Suppression Subtractive Hybridization was carried out to identify thedifferentially expressed genes in the colonized plants uponP. colocasiaeinfection. Various genes likeSenescence associated genes, cytochrome P450, Delta (12) Oleic acid desaturase and calciumdependent protein kinase that take part in different defense related pathways were identified uponBlast2Go program. The study confirms thatP. indicacan be effectively utilized for growth promotion aswell as an eco-friendly management strategy to combat taro leaf blight incidence.