In Vivo Application of Potent Probiotics for enhancing potato growth and controlling Ralstonia solancerium and Fusarium oxysporum infections

Abstract

Abstract Plant probiotics are live microbial cells or cultures that support plant growth and control plant pathogens through different mechanisms. They have various effects on plants, including plant growth promotion effects through the production of indole acetic acid (IAA), biological control activity, and production of cellulase enzyme, thus induction of systemic resistance and increasing the availability of mineral elements. The present work aims at studying the potentials of Achromobacter xylosoxidans and Bacillus safensis as plant probiotics for the field cultivation of potatoes. In vitro studies of A. xylosoxidans and B. safensis have proved their abilities to produce IAA, and cellulase as well as exhibited antimicrobial activity against two plant pathogens that infect Solanum tuberosum as Fusarium oxysporum and Ralstonia solancerium under different conditions at a broad range of temperatures and pHs. Probiotic isolates A. xylosoxidans and B. safensis were able to tolerate (ultraviolet) Radiation exposure for up to two hours, the dose-response curve exhibited that the D10 values of A. xylosoxidans and B. safensis were 28 and 16 respectively. The in vivo study of the effects of probiotics A. xylosoxidans and B. safensis on S. tuberosum grown in sandy loamy soil was detected after cultivation for 60 days. The addition of both probiotic isolates either broth or wheat separately has enhanced all the growth parameters, however, the better results and increased production was in favor of adding probiotics with broth more than wheat. In the case of adding both probiotics with broth, the shoot dry weight was increased from 28 ± 1.0 in the control to 50 ± 1.2 gm, shoot length increased from 24 ± 1 to 45.7 ± 2 cm, branches numbers increased from 40 ± 4 to 70 ± 5, leaves number increased from 99 ± 6 to 130 ± 5, root dry weight increased from 9.3 ± 1.7 to 12.9 ± 2 gm, root length increased from 24 ± 3.8 to 35.7 ± 2 cm, tuber weight increased from 15 ± 2.3 to 37.0 ± 2 gm and tuber number increased from 9 ± 1 to 24.4, and the shoot and root rot percentage was reduced to 0%. On the other hand, both probiotics showed a remarkable protective effect against potato pathogens separately and reduced the negative impact of the infection using them together.