Drought is the most important abiotic stress that restricts the genetically predetermined yield potential of the crops. In the present study, four tomato varieties: Kashi Vishesh, Kashi Aman, Kashi Abhiman, and Kashi Amrit, were used to study the effect of PGPMs (plant growth-promoting microorganisms). PGPM strains, Bacillus megaterium BHUPSB14, Pseudomonas fluorescens BHUPSB06, Pseudomonas aeruginosa BHUPSB01, Pseudomonas putida BHUPSB0, Paenibacillus polymixa BHUPSB17, and Trichoderma horzianum, were used as the consortium. The control group was irrigated up to 80% of field capacity, while 7-, 14-, and 21-day water-deficit-exposed (DWD) plants' pot soil moisture was maintained to 40, 25, and 15% of the field capacity, both with and without the PGPM inoculation condition. The physiological parameters, such as electrolyte leakage, relative water content, photosynthetic efficiency, and chlorophyll color index, were significantly improved by PGPM application under progressive drought stress, compared to the control. PGPM application enhanced the proline accumulation and reduced the formation of hydrogen peroxide and lipid peroxidation under drought stress. The plant growth attributes were significantly increased by PGPM application. The Kashi Amrit variety showed the highest fruit yield among the four varieties under all the treatments. The PGPM consortium application also improved the soil physico-biological properties and nutrient availability in the soil. The PGPM consortium used in this study can potentially mitigate drought stress on tomato in drought-prone regions and act as a biofertilizer. The present study will open a new avenue of drought stress management in tomato.

Keywords: PGPM; drought; growth attributes; soil physico-biological properties; tomato.

干旱是限制作物遗传预定产量最重要的非生物胁迫。在本研究中，使用四种番茄品种：卡什维舍什、卡什阿曼、卡什阿比曼和卡什阿密特，来研究植物促生微生物（PGPMs）的影响。使用的PGPM菌株包括 Bacillus megaterium BHUPSB14, Pseudomonas fluorescens BHUPSB06, Pseudomonas aeruginosa BHUPSB01, Pseudomonas putida BHUPSB0, Paenibacillus polymixa BHUPSB17，以及 Trichoderma horzianum。对照组灌溉至田间持水量的80%，而经历7、14和21天干旱胁迫（DWD）植物的盆土含水量分别维持在40%、25%和15%的田间持水能力，同时考虑有无PGPM接种的情况。与对照组相比，在逐步增加的干旱胁迫下，生理参数如电解质渗漏、相对含水量、光合效率和叶绿素颜色指数通过PGPM的应用得到了显著改善。PGPM的应用增强了脯氨酸积累并减少了过氧化氢和脂质过氧化的形成。植物生长特性也因PGPM应用而得到显著提升。在所有处理中，卡什阿密特品种显示出了最高的果实产量。该PGPM菌株组合还改进了土壤物理-生物性质以及土壤养分的可利用性。本研究中使用的PGPM联合体有可能减轻干旱地区番茄的干旱胁迫，并作为生物肥料使用。这项研究表明，在番茄上管理干旱胁迫的新途径。

关键词：PGPM；干旱；生长特性；土壤物理-生物性质；番茄。