2016) could be the factors affecting the decadal plummet in Assam’s tea production. Therefore, it can be assumed that poor nutrient cycling along with several major climatic variables such as average temperature, average precipitation, drought intensity, and precipitation variability (Duncan et al. The authors reported that a substantial area with pH value less than 5.5 showed severe potassium (P), calcium (Ca), magnesium (Mg), and molybdenum (Mo) deficiency with an increase in aluminum (Al) and iron (Fe) toxicities. Acidic soils are generally poor in fertility and water holding capacity. ( 2014) highlighted the alarming increase of soil acidity in the tea gardens, ranging from very strongly acidic (pH 4.9) to extremely acidic (pH 4.4) condition with low cation exchange capacity and low base saturation status (<35%). However, continuous and exhaustive cultivation and adoption of traditional practices have led to the deterioration of soil health resulting in an increase in soil acidity and aluminum toxicity. Ideally, the tea bushes prefer acidic soils with a pH range of 4.5–6.0. The state enjoys a distinct recognition as the largest tea-growing region in the world with a record number of 68,465 small tea gardens (area of 3–15 acre) and 825 large tea gardens (>15 acres) (Economic survey, Govt. Assam, a northeastern state of India plays a major role in the Indian tea industry by contributing about 53% of the country’s and around 17% of the world’s total annual tea productions (Dikshit and Dikshit 2014). Tea is one of the oldest, non-alcoholic, popular beverages of the world. This study revealed that low soil pH influences bacterial community structure and their functional properties. Results indicated that IAA and siderophore production, as well as phosphate solubilization efficiency of the isolates decreased significantly ( P ≤ 0.05) in the acidic environment. Out of the 47 isolates, 10 isolates tested positive for the entire aforesaid plant growth promoting tests and further tested for quantitative analyses for production of IAA, siderophore, and phosphate solubilization at the acidic and neutral condition. Among the 70 isolates, 47 most promising isolates were tested for their plant growth promoting activity based on the production of Indole Acetic Acid (IAA), siderophore, and HCN as well as solubilization of phosphate, zinc, and potassium. Further, 70 acid-tolerant bacterial isolates characterized using a polyphasic taxonomy approach could be grouped to the genus Bacillus, Lysinibacillus, Staphylococcus, Brevundimonas, Alcaligenes, Enterobacter, Klebsiella, Escherichia, and Aeromonas. Culture-dependent studies and phospholipid fatty acid analysis revealed a high abundance of Gram-positive bacteria. Study, we report on the bacterial diversity and their functional properties prevalent in tea garden soils of Assam that have low pH (3.8–5.5).
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