Isolation and characterization of plant growth-promoting rhizobacteria from Opuntia ficus-indica and their effect on Wheat growth

Abstract

Endophytic bacteria are found inside host plants without causing disease symptoms, and form a range of di erent bene cial rela onships. In this study, four bacterial strains were isolated from roots, cladodes and non gus- tatory fruits of Opun a cus-indicaL. collected from the Algerian semi-arid region. The bacteria were able to grow at temperatures as 45 °C. 16SrRNA sequencing revealed the iden ty of isolates as Pseudomonas pu da(E1)with 98% similarity,P. brassicacearum(E2) and Klebsiella pneumonia (E3,E4)with 99% similarity. The strains were tested in vitro for their biocontrol ac vity against phytopathogenic fungus, and found to have the ability to inhibit the Fusarium oxysporum f. sp. albedinis and Aspergillus niger growth. We noticed that the most important inhibitory effect recorded with P. pu da (69.78±3.93 and 65.15±2.8), and that the feeble antagonistic effect recorded with P. brassicacearum (20.57±6.04 and 8.52 ±2.8) against of F.oxysporum f.sp albdeinis and A.niger. The plant growth promo ng (PGP) proper es were demonstrated through wheat (Triticum aestivum L.) based bioassay under hydroponic condi ons.The inocula on of bacteria showed an increase in density, length of roots and stems, indica ng the PGP abili es of these bacteria. P. pu da showed a poten al for growth of wheat plant.We no ced respectively the length of both stems and roots (17.34 ± 0.54 mm; 11.07 ± 0.67 mm), and we found that fresh and dry weight was (0.23 ± 0.029 g; 0.0375 ±0.003 g). Overall the results showed that isolates characterized were able to improve the growth of plants, and inhibit the propaga on of phytopathogenic fungi. To our knowledge, this is the rst report describing the isola on of bacteria from O. cus-indica(L.) in Algerian semi-arid region.