Fire in pine grown regions of Himalayas depletes cultivable plant growth promoting beneficial microbes in the soil

Abstract Plant growth promoting microbes impact the life of trees, shrubs and other plant species in the forest. Fire in forest adversely affects the growth of plants directly by burning and heat stress and indirectly by affecting the survival of plant growth promoting microbes. Herein, we analyzed changes in the population of cultivable microbes owing to fire in the pine grown forest in the Indian Himalayan region. We found that soil in the burnt region predominantly harbored Gram-positive bacteria which lacked biofertilizer and biocontrol traits. Forest fire resulted in the loss of Gram-negative strains of genera Pseudomonas , Serratia , Enterobacter , Burkholderia , Klebsiella , and Pantoea . Similarly, we found that the rhizospheric region of grasses which came after the event of the fire in the pine forest lacked the beneficial Gram-negative strains. Furthermore, in plantae experiments in which pea ( Pisum sativum ) and wheat ( Triticum aestivum ) seedlings were treated with bacteria isolated from the burnt and unburnt forest bed showed that bacteria from the burnt region did not affect the growth of seedlings as compared to the bacteria isolated from the unburnt region which improved the growth of seedlings. Comparing the soil parameters between burnt and unburnt region showed a decrease in nutrients, and, increase in both bulk density and dispersion ratio due to the forest fire. Our results strongly indicate that forest fire reduces the population of cultivable beneficial microbes and this loss could have a negative impact on the growth of forest flora.