Department of Biosciences, COMSATS University, Islamabad, Pakistan.
Department of Botany, PMAS-Arid University Rawalpindi, Rawalpindi, Pakistan.
Physiol Plant. 2021 Jun;172(2):896-911. doi: 10.1111/ppl.13304. Epub 2021 Jan 5.
Research on plant growth-promoting bacteria (PGPR) revealed an effective role of bacterial volatile organic compounds (VOCs) in stress alleviation. Out of 15 PGPR strains, infection with VOCs from Pseudomonas pseudoalcaligenes' resulted in maximum germination, growth promotion, and drought tolerance in maize plants. The VOCs of P. pseudoalcaligenes caused induced systemic tolerance in maize plants during 7 days of drought stress. The VOCs exposed plants displayed resistance to drought stress by reducing electrolyte leakage and malondialdehyde content and increasing the synthesis of photosynthetic pigments, proline, and phytohormones contents. Maize plants revealed enhanced resistance by showing higher activities of antioxidant defense enzymes both in shoots and roots under drought stress. Activities of antioxidant enzymes were more pronounced in shoots than roots. Gas chromatography and mass spectrophotometric (GC-MS) analysis comparing VOCs produced by the most efficient P. pseudoalcaligenes strain and inefficient strains of Pseudomonas sp. grown in culture media revealed nine compounds that they had in common. However, dimethyl disulfide, 2,3-butanediol, and 2-pentylfuran were detected only in P. pseudoalcaligenes, indicating these compounds are potential candidates for drought stress induction. Further studies are needed to unravel the molecular mechanisms of VOCs-mediated systemic drought tolerance in plants related to each identified VOC.
植物促生菌（PGPR）的研究揭示了细菌挥发性有机化合物（VOCs）在缓解胁迫方面的有效作用。在 15 株 PGPR 菌株中，感染 Pseudomonas pseudoalcaligenes 的 VOC 可使玉米植株的发芽、生长和耐旱性达到最大值。在 7 天的干旱胁迫期间，P. pseudoalcaligenes 的 VOC 会在玉米植株中引起诱导性系统耐受。暴露于 VOC 的植物通过降低电解质渗漏和丙二醛含量、增加光合色素、脯氨酸和植物激素含量的合成来表现出对干旱胁迫的抗性。在干旱胁迫下，玉米植株在地上部和根部均显示出更高的抗氧化防御酶活性，从而表现出更高的抗性。与在培养基中生长的最有效 P. pseudoalcaligenes 菌株和低效 Pseudomonas sp. 菌株产生的 VOCs 进行气相色谱和质谱（GC-MS）分析比较，发现它们有 9 种共同的化合物。然而，二甲基二硫醚、2,3-丁二醇和 2-戊基呋喃仅在 P. pseudoalcaligenes 中检测到，表明这些化合物是诱导干旱胁迫的潜在候选物。需要进一步的研究来揭示与每个鉴定出的 VOC 相关的 VOC 介导的植物系统耐旱性的分子机制。
