Scholarlink

<p>This study evaluated whether <i>Azospirillum brasilense</i> can complement mineral N fertilization and improve tomato performance under saline conditions. Tomato plants were inoculated with either the wild-type <i>A. brasilense</i> Sp7 (N-fixing) or its nitrogenase-deficient mutant <i>Nif-</i> (non-N-fixing) and exposed to NaCl concentrations ranging from 0 to 120 mM. At moderate salinity (30–90 mM NaCl), Sp7 inoculation enhanced root development, biomass accumulation, ion homeostasis, antioxidant activity, proline content, and total N accumulation, while upregulating key genes involved in N assimilation, indicating improved N metabolism and stress adaptation. Both bacterial strains conferred benefits compared with uninoculated controls, suggesting that inoculation per se, likely through auxin-mediated effects, supports plant resilience. Under severe salinity (120 mM NaCl), however, the performance of Sp7 declined, possibly reflecting the energetic constraints and downregulation of N-metabolism pathways under extreme stress, whereas <i>Nif-</i> maintained more stable antioxidant responses but lacked the growth advantage of Sp7 These results reveal that inoculation with <i>A. brasilense</i> enhances tomato tolerance to salinity through combined phytohormonal and N-assimilation mechanisms. The contrasting performance of Sp7 and <i>Nif-</i> underscores the context-dependent nature of PGPR efficacy and delineates the thresholds beyond which N-fixation no longer provides added value.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Enhancing Salt Tolerance in Tomato by Complementing Mineral N Fertilization with Azospirillum Brasilense Inoculation: Contrasting Roles of the N-fixing Sp7 and its Nif- Mutant

  • 期刊论文

  • 出版模式：

    开放获取

  • 发表日期：

    2026年2月19日

查看全文
  • Mónica Yorlady Alzate Zuluaga,
  • Mariateresa Coppola,
  • Amna Chaudhry,
  • Sonia Monterisi,
  • Talita de Oliveira Caretta,
  • Fabio Valentinuzzi,
  • Stefano Cesco,
  • Youry Pii

摘要

This study evaluated whether Azospirillum brasilense can complement mineral N fertilization and improve tomato performance under saline conditions. Tomato plants were inoculated with either the wild-type A. brasilense Sp7 (N-fixing) or its nitrogenase-deficient mutant Nif- (non-N-fixing) and exposed to NaCl concentrations ranging from 0 to 120 mM. At moderate salinity (30–90 mM NaCl), Sp7 inoculation enhanced root development, biomass accumulation, ion homeostasis, antioxidant activity, proline content, and total N accumulation, while upregulating key genes involved in N assimilation, indicating improved N metabolism and stress adaptation. Both bacterial strains conferred benefits compared with uninoculated controls, suggesting that inoculation per se, likely through auxin-mediated effects, supports plant resilience. Under severe salinity (120 mM NaCl), however, the performance of Sp7 declined, possibly reflecting the energetic constraints and downregulation of N-metabolism pathways under extreme stress, whereas Nif- maintained more stable antioxidant responses but lacked the growth advantage of Sp7 These results reveal that inoculation with A. brasilense enhances tomato tolerance to salinity through combined phytohormonal and N-assimilation mechanisms. The contrasting performance of Sp7 and Nif- underscores the context-dependent nature of PGPR efficacy and delineates the thresholds beyond which N-fixation no longer provides added value.