Scholarlink

<p>This study investigated the effects of plant growth-promoting rhizobacteria (PGPR) on <i>Ocimum basilicum</i> under salt stress, focusing on morphological, physiological, biochemical, essential oil composition, and gene expression responses. The factorial greenhouse experiment included three salinity levels (0, 75, and 150 mM NaCl) and four PGPR treatments (<i>Pseudomonas fluorescens</i>, <i>Bacillus subtilis</i>, <i>Alcaligenes faecalis</i>, and a non-inoculated control). Morphological traits such as seedling length, shoot dry weight, and root dry weight improved significantly with <i>B. subtilis</i>, increasing by 47.6%, 47.7%, and 27.8%, respectively, under moderate salinity. Physiological parameters, including photosynthetic rate, stomatal conductance, and transpiration, were highest in <i>B. subtilis</i>-inoculated plants, with increases of 48.7%, 37.8%, and 33.9% under severe salinity. Biochemical attributes such as total chlorophyll (42.0%), proline (38.8%), phenolics (38.7%), and flavonoids (35.7%) were highest in <i>B. subtilis</i>-treated plants. PGPR significantly reduced oxidative stress, with <i>B. subtilis</i> decreasing H₂O₂ (54.3%), MDA (36.7%), and electrolyte leakage (32.8%). Essential oil yield declined under stress, but PGPR, especially <i>P. fluorescens</i> and <i>B. subtilis</i>, preserved oil content, reaching 1.04% and 0.97%, respectively, at 150 mM NaCl. Additionally, PGPR altered essential oil composition, with <i>B. subtilis</i> increasing linalool (34.05%) and 1,8-cineole (15.82%). Molecular analysis revealed that PGPR significantly upregulated essential oil biosynthetic genes (<i>C7OMT</i>, <i>EOMT</i>, <i>LIS</i>, <i>MTS</i>), with <i>P. fluorescens</i> inducing the highest expression levels of <i>C7OMT</i> (6.02-fold) and <i>EOMT</i> (7.86-fold), and <i>B. subtilis</i> showing the strongest upregulation of <i>EOMT</i> (8.87-fold) and <i>MTS</i> (7.12-fold). These findings highlight PGPR, particularly <i>B. subtilis</i> and <i>P. fluorescens</i>, as effective agents in enhancing basil growth, stress tolerance, and essential oil production under salinity stress, making them promising candidates for sustainable agriculture.</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

Exploring the potential of PGPR to enhance basil tolerance to salinity stress: insights into growth, biochemistry, and essential oil production

  • 期刊论文

  • 发表日期：

    2026年3月10日

查看全文
  • Zaniar Jamal Salih,
  • Farhan Ahmad Abdulrahman,
  • Sahar Hussein Hamarashid,
  • Dastan Jamal Salih

摘要

This study investigated the effects of plant growth-promoting rhizobacteria (PGPR) on Ocimum basilicum under salt stress, focusing on morphological, physiological, biochemical, essential oil composition, and gene expression responses. The factorial greenhouse experiment included three salinity levels (0, 75, and 150 mM NaCl) and four PGPR treatments (Pseudomonas fluorescens, Bacillus subtilis, Alcaligenes faecalis, and a non-inoculated control). Morphological traits such as seedling length, shoot dry weight, and root dry weight improved significantly with B. subtilis, increasing by 47.6%, 47.7%, and 27.8%, respectively, under moderate salinity. Physiological parameters, including photosynthetic rate, stomatal conductance, and transpiration, were highest in B. subtilis-inoculated plants, with increases of 48.7%, 37.8%, and 33.9% under severe salinity. Biochemical attributes such as total chlorophyll (42.0%), proline (38.8%), phenolics (38.7%), and flavonoids (35.7%) were highest in B. subtilis-treated plants. PGPR significantly reduced oxidative stress, with B. subtilis decreasing H₂O₂ (54.3%), MDA (36.7%), and electrolyte leakage (32.8%). Essential oil yield declined under stress, but PGPR, especially P. fluorescens and B. subtilis, preserved oil content, reaching 1.04% and 0.97%, respectively, at 150 mM NaCl. Additionally, PGPR altered essential oil composition, with B. subtilis increasing linalool (34.05%) and 1,8-cineole (15.82%). Molecular analysis revealed that PGPR significantly upregulated essential oil biosynthetic genes (C7OMT, EOMT, LIS, MTS), with P. fluorescens inducing the highest expression levels of C7OMT (6.02-fold) and EOMT (7.86-fold), and B. subtilis showing the strongest upregulation of EOMT (8.87-fold) and MTS (7.12-fold). These findings highlight PGPR, particularly B. subtilis and P. fluorescens, as effective agents in enhancing basil growth, stress tolerance, and essential oil production under salinity stress, making them promising candidates for sustainable agriculture.