Beneficial Fungal Root Endophyte Piriformospora indica Diminishes Yield Loss Without Compromising Quality of Banana Fruits Due to Banana bract mosaic virus Infection through Better Soil Nutrient Mobilization

Aims: Banana bract mosaic virus (BBrMV) is a significant viral disease that adversely impacts the yield and quality of banana (Musa acuminata) fruits. Endophytes have been recognized as a sustainable tool to enhance plant nutrient availability and uptake. Piriformospora indica is a beneficial fungal root endophyte that can improve nutrient utilization and confer tolerance to diverse abiotic and biotic stresses in banana plants. The effect of P. indica colonization on nutrient assimilation and fruit quality of BBrMV-infected banana plants still needs to be better understood, particularly in the humid tropical environments of southern laterites of Kerala. P. indica promotes both fruit size and quality, leading to an overall improvement of fruit attributes viz., fruit length, width, colour, TSS, acidity, moisture, and ash content etc., An experiment comprising four treatments with five replications revealed that P. indica colonization enhanced potassium concentration at the rhizosphere (603 Kg ha-1), whereas decreased in the diseased plants (318 Kg ha-1). The nutrient concentration in the rhizosphere recorded a substantial relation with disease severity. Compared to P. indica colonized plants, the uptake of N, P, K, Ca, Mg, S and B by BBrMV infected plants exhibited 36.5, 37.6, 57.5, 44.1, 23.3, 43.7 and 48.9 per cent reduction respectively. Hence, pre-colonization of P. indica improved the nutrient mobilization (in soil), uptake and accumulation (in fruit) in the BBrMV infected banana plants compared to the virus alone infected plant. Fruits from P. indica pre-colonized plants challenged with the virus exhibited an enhanced K (515.5 ± 6.25 mg 100g -1) and Fe (0.42 ± 0.04 mg 100 g-1) content along with high total soluble sugars (27.25oBrix), titrable acidity (0.48%) and ash content (1.14%) compared to healthy and virus infected plants. Hence, this can instigate the appropriate sustainable virus disease management strategies in banana plants, emphasizing its improved fruit quality through nutrient assimilation.