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ARS Home » Plains Area » Fort Collins, Colorado » Center for Agricultural Resources Research » Soil Management and Sugarbeet Research » Research » Publications at this Location » Publication #346203
Research Project: Management Practices for Long Term Productivity of Great Plains Agriculture

Location: Soil Management and Sugarbeet Research

Title: Water stress tolerance of winter wheat (Triticum aestivum L.) genotypes is improved by ACC deaminase bacteria

Author
item SALEM, GALAL - Colorado State University
item WEIR, TIFFANY - Colorado State University
item BYRNE, PATRICK - Colorado State University
item STROMBERGER, MARY - Colorado State University
item Manter, Daniel
item EL-FEKI, WALID - Alexandria University Of Egypt

Submitted to: Functional Plant Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/9/2018
Publication Date: 8/10/2018
Citation: Salem, G., Weir, T., Byrne, P., Stromberger, M., Manter, D.K., El-Feki, W. 2018. Water stress tolerance of winter wheat (Triticum aestivum L.) genotypes is improved by ACC deaminase bacteria. Functional Plant Biology. 8:1-7.

Interpretive Summary: The current study examined the ability of ACC+ (1-aminocyclopropane-1-carboxylic acid deaminase) to promote drought tolerance of seven winter wheat genotypes in a greenhouse study. This study demonstrated the effectiveness of ACC+ bacteria for inducing water stress tolerance and consequently improving the growth of winter wheat genotypes under water-stressed condition. However, the ability of ACC+ bacteria to promote water stress tolerance was genotype-specific. For example, inoculation with ACC+ bacteria resulted in increased leaf RWC, root biomass, root length and root length within specific diameter classes in the deepest tube section for RonL. Without water stress, inoculation significantly increased aboveground biomass for RonL and TAM112 and also increased root length within specific diameter class for TAM112. Collectively, the results of the present study revealed that the growth response of winter wheat to inoculation with ACC+ bacteria was genotype dependent. This variation in growth promotion effects among genotypes might be due to a unique root exudate profile for certain wheat genotypes and their abilities to preserve relatively large proportions of ACC+ bacteria in the rhizosphere, and should be further examined. According to the results obtained, inoculation of certain wheat genotypes with ACC+ bacteria has the potential to improve root growth at depth and presumably improve water uptake from deep soil layer, thereby reducing the deleterious effects of water stress on the growth of wheat genotypes. However, a better understanding of this variation and how it improves root acquisition of water at depth to increase crop productivity under water stress is needed.

Technical Abstract: Aims: We examined the effects of inoculation with 1-aminocyclopropane-1-carboxylic acid (ACC)-deaminase containing (ACC+) bacteria on different winter wheat genotypes under water stress. We hypothesized that sensitivity of winter wheat to water stress would vary by genotype, and that inoculation with ACC+ bacteria would improve wheat growth under water stress, but that the effect would also be genotype dependent. Methods: Seven wheat genotypes were grown in 1-m deep root tubes in greenhouse study, with or without ACC+ bacteria inoculation, under well-watered (WW) or water-stressed (WS) conditions. Results: Inoculation significantly increased leaf relative water content (RWC) across all wheat genotypes; the effect was most notable for RonL, whose RWC increased by 28% when inoculated and grown under the water-stressed condition, compared with non-inoculated control. Under water-stressed condition, inoculation had no significant effect on wheat above-ground biomass. However, under well-watered condition, inoculation significantly increased above-ground biomass for TAM112 and RonL, by 32% and 38%, respectively. In both irrigation conditions, inoculation significantly increased root biomass in the deepest tube section (67-99 cm depth increment) for only RonL by 155% under water-stressed condition, whereas in well-watered conditions root biomass increased by 150%, as compared to non-inoculated controls. A positive effect of inoculation with ACC+ bacteria on total root length was detected for RonL in the bottom tube section, under water-stressed condition. Moreover, under water stress condition, inoculation significantly increased root length by 78%-134% within the 0.50-0.75 and 0.75-1 mm diameters range, respectively, for RonL in comparison with the non-inoculated controls. Under well-watered condition, inoculation with ACC+ bacteria significantly increased root lengths within the 0.05-0.75 mm diameter class for TAM112 by 40%. Conclusion: Under the WS condition, inoculation with ACC+ bacteria resulted in increased leaf RWC, root biomass, root length and root length within specific diameter classes in the deepest tube section for RonL. Under the WW condition, inoculation significantly increased aboveground biomass for RonL and TAM112 and also increased root length within specific diameter class for TAM112. Collectively, the results of the present study revealed that the growth response of winter wheat to inoculation with ACC+ bacteria was genotype dependent.