Climate change and drought have significant effects on crop growth, with reduced rainfall and changing precipitation patterns, including sudden heavy rain or prolonged drought, causing damage to plant growth. The supply of water is identified as the most critical environmental factor influencing crop growth. Tomato, a globally important vegetable crop, occupies nearly 6 million hectares of cultivation worldwide, with an annual production exceeding 200 million tons. The production process is severely affected when subjected to water scarcity conditions.

This project investigates key growth indicators of tomato plants under water deficit conditions to determine criteria for tomato water deficiency. It also analyzes the microbial community in the root zone, aiming to identify microorganisms that could serve as targets for drought-tolerant crop monitoring or even contribute to strategies for mitigating drought.

The experimental results reveal that using the severity rating of early blight as a visual criterion for plant wilting correlates significantly with plant growth conditions (dry weight, plant water content) and soil moisture content. This suggests that wilting rate could be used as an initial indicator for drought tolerance. Based on these indicators, 11 tomato varieties (lines) were screened, identifying the most drought-tolerant (LA716, S6) and least drought-tolerant (US, TN-AV_19, TY-AV_20).

 DNA from the root zones of drought-tolerant and non-drought-tolerant varieties was subjected to next-generation sequencing for microbial community analysis. The results showed a total classification of 24 phyla, 60 classes, 142 orders, 216 families, 330 genera, and 544 species in the microbial community. In the microbial community of the drought-tolerant variety S6, the family Micrococcaceae, particularly the Paenarthrobacter, was predominant. Some species in this genus are known for promoting plant growth, enhancing plant stress tolerance, and exhibiting resistance to plant pathogenic fungi. This suggests their potential as priority targets for future research.

▲Fig. 1. An investigation of wilting rates among different tomato varieties under various durations of water withholding is depicted in the left figure for the first experiment and the right figure for the second experiment

▲Fig. 2. Genus-level fungal community analysis revealed that the drought-tolerant variety S6 exhibited the highest proportion within the genus Paenarthrobacter, a member of the Micrococcaceae family. Some species within this genus possess abilities such as promoting plant growth, enhancing plant stress tolerance, and resisting plant pathogenic fungi.

▲Fig. 3. Investigation of wilting rates among different tomato varieties under treatment with different strains of bacteria and various durations of water withholding is shown in the left figure for water treatment, the middle figure for treatment with P. ureafaciens strain 7, and the right figure for treatment with P. ureafaciens strain 14.