Zafar Sultan*, Aminu Imam, Abdulmumin A. Nuhu, Minjibir A, Muhammad SI
Plant Growth-Promoting Rhizobacteria (PGPR) are able to promote plant growth and/or induce local and systemic resistance against biotic and abiotic stresses, but the stability and durability of their efficiency still need more investigation. The present work aims to identify a compatible-PGPR-mixture effective to stimulate wheat growth, resistance against Mycosphaerella graminicola, the causal agent of Septoria tritici leaf Blotch (STB), and tolerance to drought stress.
The interactions between twenty-six PGPR and four wheat cultivars with different resistance levels to STB, in individual and co-inoculations, were tested. The results demonstrated higher external and internal root colonisation potential of Paenibacillus sp. strain B2 (PB2) in a mixture, referred hereafter as Mix-3, with strains Arthrobacter sp. SSM-004 and Microbacterium sp. SSM-001, and without an impact of wheat genotype and growth stage, as observed in its individual inoculations. Only with Mix-3 was wheat growth promotion observed. Interestingly, PB2 and Mix-3 eliminated the negative impact of drought stress on the Foliar Dry Biomass (FDB) and Root Dry Biomass (RDB).
Only in a mixture of three-compatible-PGPR (Mix-3) was plant growth promotion observed and the tolerance induced to drought stress was more effective. However, it seems that resistance induced against STB is PB2-dependent.