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Vázquez KRJ, López-Hernández J, García-Cárdenas E, Pelagio-Flores R, López-Bucio JS, Téxon AC, Ibarra-Laclette E, López-Bucio J. The plant growth promoting rhizobacterium Achromobacter sp. 5B1, rescues Arabidopsis seedlings from alkaline stress by enhancing root organogenesis and hormonal responses. Microbiol Res 2024; 281:127594. [PMID: 38211416 DOI: 10.1016/j.micres.2023.127594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 12/21/2023] [Accepted: 12/23/2023] [Indexed: 01/13/2024]
Abstract
Soil alkalinity is a critical environmental factor for plant growth and distribution in ecosystems. An alkaline condition (pH > 7) is imposed by the rising concentration of hydroxides and cations, and prevails in semiarid and arid environments, which represent more than 25% of the total arable land of the world. Despite the great pressure exerted by alkalinity for root viability and plant survival, scarce information is available to understand how root microbes contribute to alkaline pH adaptation. Here, we assessed the effects of alkalinity on shoot and root biomass production, chlorophyll content, root growth and branching, lateral root primordia formation, and the expression of CYCB1, TOR kinase, and auxin and cytokinin-inducible trangenes in shoots and roots of Arabidopsis seedlings grown in Petri plates with agar-nutrient medium at pH values of 7.0, 7.5, 8.0, 8.5, and 9.0. The results showed an inverse correlation between the rise of pH and most growth, hormonal and genetic traits analyzed. Noteworthy, root inoculation with Achromobacter sp. 5B1, a beneficial rhizospheric bacterium, with plant growth promoting and salt tolerance features, increased biomass production, restored root growth and branching and enhanced auxin responses in WT seedlings and auxin-related mutants aux1-7 and eir1, indicating that stress adaptation operates independently of canonical auxin transporter proteins. Sequencing of the Achromobacter sp. 5B1 genome unveiled 5244 protein-coding genes, including genes possibly involved in auxin biosynthesis, quorum-sensing regulation and stress adaptation, which may account for its plant growth promotion attributes. These data highlight the critical role of rhizobacteria to increase plant resilience under high soil pH conditions potentially through genes for adaptation to an extreme environment and bacteria-plant communication.
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Affiliation(s)
- Kirán Rubí Jiménez Vázquez
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Edificio B3, Ciudad Universitaria, C. P., 58030 Morelia, Michoacán, Mexico
| | - José López-Hernández
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Edificio B3, Ciudad Universitaria, C. P., 58030 Morelia, Michoacán, Mexico
| | - Elizabeth García-Cárdenas
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Edificio B3, Ciudad Universitaria, C. P., 58030 Morelia, Michoacán, Mexico
| | - Ramón Pelagio-Flores
- Facultad de Químico Farmacobiología, Universidad Michoacana de San Nicolás de Hidalgo, Avenida Tzintzuntzan 173; Col. Matamoros, 58240 Morelia, Michoacán, Mexico
| | - Jesús Salvador López-Bucio
- Catedrático CONACYT-Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Edificio B3, Ciudad Universitaria, C. P., 58030 Morelia, Michoacán, Mexico
| | - Anahí Canedo Téxon
- Red de Estudios Moleculares Avanzados, Instituto de Ecología A.C., Carretera Antigua a Coatepec 351, El Haya, C.P. 91070, Xalapa, Ver, Mexico; Departamento de la Conservación de la Biodiversidad, El Colegio de la Frontera Sur., Carretera Villahermosa-Reforma Km 15.5, Ranchería el Guineo, Sección II C.P., 86280 Villahermosa, Tabasco, Mexico
| | - Enrique Ibarra-Laclette
- Red de Estudios Moleculares Avanzados, Instituto de Ecología A.C., Carretera Antigua a Coatepec 351, El Haya, C.P. 91070, Xalapa, Ver, Mexico
| | - José López-Bucio
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Edificio B3, Ciudad Universitaria, C. P., 58030 Morelia, Michoacán, Mexico.
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