PGP-Bacterium Pseudomonas protegens Improves Bread Wheat Growth and Mitigates Herbicide and Drought Stress

Abstract

The reaction of plants to simultaneous stress action and treatment with biological stimulants still remains poorly studied. Laboratory and field experiments have been conducted to study the growth and yield of bread wheat (Triticum aestivum L.) of the variety Ekada 113; stress markers and quantitative ratios of phytohormones in plants under insufficient soil moisture; the effects of spraying with herbicide containing 2,4-D and dicamba and growth-stimulating bacterium Pseudomonas protegens DA1.2; and combinations of these factors. Under water shortage conditions, spraying plants with Chistalan reduced their growth compared to non-sprayed plants, which was associated with inhibition of root growth and a decrease in the content of endogenous auxins in the plants. Under conditions of combined stress, the treatment of plants with the strain P. protegens DA1.2 increased the IAA/ABA ratio and prevented inhibition of root growth by auxin-like herbicide, ensuring water absorption by the roots as well as increased transpiration. As a result, the content of malondialdehyde oxidative stress marker was reduced. Bacterization improved the water balance of wheat plants under arid field conditions. The addition of bacterium P. protegens DA1.2 to the herbicide Chistalan increased relative water content in wheat leaves by 11% compared to plants treated with herbicide alone. Application of the bacterial strain P. protegens DA1.2 increased the amount of harvested grain from 2.0–2.2 t/ha to 3.2–3.6 t/ha. Thus, auxin-like herbicide Chistalan and auxin-producing bacterium P. protegens DA1.2 may affect the balance of phytohormones in different ways. This could be the potential reason for the improvement in wheat plants’ growth during dry periods when the bacterium P. protegens DA1.2 is included in mixtures for weed control.

Effect of Plant Growth-Promoting Bacteria on Antioxidant Status, Acetolactate Synthase Activity, and Growth of Common Wheat and Canola Exposed to Metsulfuron-Methyl

“…For canola, against the background of metsulfuron-methyl, this effect was shown for the first time. However, it was previously observed when combining other crops with herbicides of a different chemical nature [ 16 , 17 , 18 , 19 , 20 ]. The study of Ibrahim et al [ 38 ] concluded that foliar spray of pongamia oil alleviated the toxic effects of glyphosate on tomato plants in the form of increased root and shoot biomass while reducing MDA and O2.…”

“…Motamedi et al [ 17 ] described a positive effect of the native plant growth-promoting bacteria on plant biomass in the presence and absence of imazethapyr herbicide. The protective effect of strains of Pseudomonas putida [ 18 ], P. protegens DA1.2 [ 19 ], P. chlororaphis PAS18 [ 20 ], and Azotobacter salinestris KF470807 [ 21 ] was studied. In the described experiments, an improvement in the growth of agricultural plants and the reduction of herbicide stress manifestations after spraying with bacterial cultures were recorded.…”

The Effects of Seed Pretreatment with Endophytic Bacteria Bacillus subtilis on the Water Balance of Spring and Winter Wheat Seedlings under Short-Time Water Deficit

“…The interactions between the microorganisms of plant rhizospheres are complex and may be negative [ 7 , 11 , 12 ], neutral, or beneficial on the basis of their effects on plant growth [ 13 ]. It is necessary to investigate all aspects of the life of plant growth-promoting (PGP) microorganisms, which provide benefits for plants due to the consortium effect and alleviate drought stress in crop plants [ 13 , 14 ], thereby improving growth and productivity [ 9 , 15 , 16 , 17 , 18 , 19 , 20 ]. Some bacterial isolates simultaneously are able not only to increase the growth of agricultural plants such as wheat, but are also able to decrease the growth of grass weed [ 7 , 21 ] and fungal diseases of wheat [ 7 , 22 ].…”

“…Pseudomonas fluorescens BRG100 produces substances with herbicidal activity on weed pest and could be used as bioherbicide [ 23 ]. The mechanisms of beneficial action of PGP bacteria and fungi for plant organisms involve releasing a wide range of important secondary metabolites: phytohormones [ 10 , 19 , 23 , 24 , 25 , 26 ] and organic and amino acids [ 12 , 24 , 25 ]. PGP bacteria could also enhance: photosynthesis [ 17 , 27 , 28 , 29 ], the nutrient uptake by solubilizing inorganic elements [ 7 , 25 , 28 , 29 , 30 ]; the biosynthesis of siderophores [ 10 , 13 , 16 , 20 , 25 ]; antioxidant defense systems [ 7 , 13 , 25 , 28 , 29 ]; and stress-responsive genes expression [ 13 , 15 , 16 , 19 , 26 , 31 , 32 ] under the influence of stress factors.…”

“…The mechanisms of beneficial action of PGP bacteria and fungi for plant organisms involve releasing a wide range of important secondary metabolites: phytohormones [ 10 , 19 , 23 , 24 , 25 , 26 ] and organic and amino acids [ 12 , 24 , 25 ]. PGP bacteria could also enhance: photosynthesis [ 17 , 27 , 28 , 29 ], the nutrient uptake by solubilizing inorganic elements [ 7 , 25 , 28 , 29 , 30 ]; the biosynthesis of siderophores [ 10 , 13 , 16 , 20 , 25 ]; antioxidant defense systems [ 7 , 13 , 25 , 28 , 29 ]; and stress-responsive genes expression [ 13 , 15 , 16 , 19 , 26 , 31 , 32 ] under the influence of stress factors. PGP bacteria also induced the synthesis of phytohormones auxins, cytokinins, gibberellins, salicylic acid, and abscisic acid (ABA) in plants [ 14 , 25 ].…”