Effect of endophytic bacteria from Algerian prickly pear roots on wheat under drought stress

Abstract

Cactus are among the most drought tolerant plants. As Opuntia is able to grow under the stress of drought, this study aims to check if endophytic bacteria isolated from cactus roots have beneficial potential for crops such as wheat during drought. Two endophytic bacterial isolates were isolated from the roots of the cactus and screened for their plant growth promoting characteristics, such as N-free growth and auxin production. These bacteria have demonstrated their potential to promote the growth of durum wheat under in-vitro conditions and have been identified as Pseudomonas putida and P.brassicacearum, following the sequencing of the 16S rRNA gene and phylogenetic analysis, and significantly improved growth parameters such as seeding length compared to the unobstructed control. After 05 days of contact of the two bacteria, P.putida and P.brassicacearum, with sprouted wheat seeds, a root growth rate of (39.88% and 62.14%, respectively) was recorded. The same effect on the growth of wheat roots is caused by the volatile substances of these bacteria deposited separately, with a rate of (53.30% and 24.18%) respectively. Symptoms of drought stress were visibly reduced on seedlings inoculated with P.putida and P.brassicacearum bacteria, a result supported by a growth rate of root parameters in length (260.83% and 179.60%), surface (21.98% and 60.17%) and scope (59.46% and 62.67%), respectively. This work opens up many perspectives for the characterization and selection of endophyte bacteria of under-used drought-tolerant species such as cacti for the improvement of the growth of field crops. These results promote the deployment of Pseudomonas sp as an effective biofertilizer in wheat.