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Among the biotic stresses, wilt disease severely affects tomato quality and productivity globally. The causal organism of this disease is Fusarium oxysporum f. sp. lycopersici (Fol), which is very well known and has a significant impact on the productivity of other crops as well. Efforts have been made to investigate the effect of plant growth-promoting bacteria (PGPB) on alleviating tomato wilt disease. Four PGPB strains, such as Pseudomonas aeruginosa BHUPSB01 (T1), Pseudomonas putida BHUPSB04 (T2), Paenibacillus polymyxa BHUPSB16 (T3), and Bacillus cereus IESDJP-V4 (T4), were used as inocula to treat Fol- challenged plants. The results revealed that PGPB treatments T1, T2, T3, and T4 were able to decrease the severity of Fusarium wilt in the tomato plants at different levels. Among the treatments, T3 displayed the strongest protective effect, with the lowest disease frequency, which was 15.25%. There were no significant differences observed in parameters such as fruit yield and relative water content in the PGPB-inoculated plants, although T3 and T4 showed minimal electrolyte leakage. Significant changes in chlorophyll fluorescence were also recorded. A lower level of H2O2 and malondialdehyde (MDA) was observed in the T3 and T4 treatments. In addition, proline accumulation was highest in the T3-treated plants. Antioxidative enzyme activities, such as catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD), significantly increased in the PGPB-treated plants. Furthermore, the highest phenylalanine ammonia-lyase (PAL) and polyphenol oxidase (PPO) activity was reported in the T3 and T4 plants, respectively. The PGPB-treated plants showed elevated expression of the PAL, PPO, PR3, PR2, SOD, CAT , and PO genes. This study's results reveal that PGPB strains can be utilized as biocontrol agents (BCAs) to enhance tomato resistance against Fusarium wilt. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Tomato production is severely affected by abiotic stresses (drought, flood, heat, and salt) and causes approximately 70% loss in yield depending on severity and duration of the stress. Drought is the most destructive abiotic stress and tomato is very sensitive to the drought stress, as cultivated tomato lack novel gene(s) for drought stress tolerance. Only 20% of agricultural land worldwide is irrigated, and only 14.51% of that is well-irrigated, while the rest is rain fed. This scenario makes drought very frequent, which restricts the genetically predetermined yield. Primarily, drought disturbs tomato plant physiology by altering plant–water relation and reactive oxygen species (ROS) generation. Many wild tomato species have drought tolerance gene(s); however, their exploitation is very difficult because of high genetic distance and pre- and post-transcriptional barriers for embryo development. To overcome these issues, biotechnological methods, including transgenic technology and CRISPR-Cas, are used to enhance drought tolerance in tomato. Transgenic technology permitted the exploitation of non-host gene/s. On the other hand, CRISPR-Cas9 technology facilitated the editing of host tomato gene(s) for drought stress tolerance. The present review provides updated information on biotechnological intervention in tomato for drought stress management and sustainable agriculture. [ABSTRACT FROM AUTHOR]