Investigating the Interaction of Endophytic Bacteria and Biochemical Compounds in Pearl Millet (Pennisetum glaucum)

Pearl millet (Pennisetum glaucum) is an important cereal crop in Asia and Africa. This study focuses on quantifying endophytic bacteria in several parts of the pearl millet plant—roots, stems, and leaves. Total phenolic content, orthodihydroxy phenols, total soluble sugars, protein levels, and enzymatic activity (peroxidase, polyphenol oxidase, and catalase) were all measured and linked with the amount of endophytic bacteria. The leaves have the highest total phenolic content, followed by the stem. Orthodihydroxy phenols were also significantly greater in leaves (1.82 mg catechol equi./g) than in stems and roots. Total soluble sugars showed higher levels in leaves (9.97 mg glucose equi./g), in stems (9.21 mg glucose equi./g) and in roots ( 6.83 mg glucose equi./g). Protein content exhibited significant variation among the plant parts, with leaves (10.63%) containing the highest protein content followed by stems and roots (8.47% and 6.67% respectively). Enzymatic activities, crucial for plant defence and growth, varied across the plant sections. Peroxidase activity was highest in roots (359.98 OD/g), followed by stems and leaves. Polyphenol oxidase activity was lowest in the roots (1.63 OD/g) and highest in the leaves with 2.19 OD/g, while catalase activity was the highest activity in the roots with 17.79 OD/g versus 14.79 OD/g and 14.63 OD/gin the leaves and Roots respectively. The number of Pearl millet endophytic bacteria in the roots is 16, whereas the amount in the stem is 12 and 10 in the leaves. This in-depth analysis sheds light on future research targeted at better understanding plant-microbe interactions and developing ways to improve plant health and productivity.