Jan Paulini (Rheinisch-Westfälische Technische Hochschule Aachen, RWTH)
Jan Paulini's Master thesis was awarded with the Prize for the Best Plant Science Master Thesis, which was carried out at Rheinisch-Westfälische Technische Hochschule Aachen (RWTH) in the year 2023 with the title:
Root-Colonizing Pseudomonads Confer Salt Tolerance in Plants
Paulini established a new hydroponic system to monitor and compare the physiological status of sugar beets (Beta vulgaris) under salt stress conditions and thereby provided the means to investigate and prove the significant salt stress alleviating capabilities of the tested plant growth-promoting rhizobacteria.
The sugar beet (Beta vulgaris) is a globally important crop, with 35 % of worldwide sugar production derived from it. It also provides essential raw materials for livestock feed and bioethanol. Due to unsustainable farming practices and rising temperatures, sugar beets frequently suffer from drought and soil salinization. These abiotic factors are the most significant limitations on sugar beet yield, causing a 33 % yield loss on average.
This study established a new system to monitor and compare the physiological status of B. vulgaris under salt stress conditions. The setup provided the means to investigate the salt stress alleviating capabilities of the PGPR Pseudomonas sp. TE7 from the Pseudomonas mandelii subgroup and Pseudomonas sp. TE13 from the Pseudomonas fluorescens subgroup.
The sugar beets were grown in a hydroponic system and in sand in the greenhouse while treated with the respective bacteria strains. Salt stress was applied to the plants, and the stress responses and bacteria-related response alterations were analysed. The bacteria were tested to be present on sugar beet roots during the evaluated 21 days. Inhabitation of the plant led to significant plant growth promoting and salt stress alleviating influence on sugar beets. Thus, both strains increased the relative leaf water content and the dry weight of salt-stressed sugar beets. Particularly, Ps. sp. TE13 had a distinct impact on the fitness of the photosynthesis machinery of salt-stressed plants, enhancing its efficiency, the capacity, and the effective quantum yield of the photosystem II while additionally increasing the photo pigment concentrations in unstressed plants. In contrast, Ps. sp. TE7 mitigated the photochemical energy dissipation.
Furthermore, quantitative real-time PCR led to the discovery that both strains induced an elevation in ascorbate peroxidase coding gene expression in sugar beets exposed to salt stress. These findings indicate that Ps. sp. TE13 and Ps. sp. TE7 can alleviate the negative implications of the natural stress response of B. vulagris to salinity. This contributes to the emerging field of plant-microbe interactions, which has the potential to enhance crop productivity and resilience, paving the way for more eco-friendly and effective agricultural strategies in the face of a changing climate and increasing food demands.
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Jan Paulini conducted this work at the Institute of Plant Physiology in Prof. Dr. Uwe Conrath’s group.
