Tomato (Solanum lycopersicum) is an economically important vegetable crop, but its growth, yield, and quality are highly vulnerable to water shortages and soil salinization. These stresses can restrict photosynthesis, disturb water balance, damage cell membranes, and trigger excessive accumulation of reactive oxygen species. Ethylene response factors regulate many plant responses by activating or repressing downstream genes, and several members of this protein family have been linked to stress adaptation. However, the tomato ERF.J subfamily, comprising SlERF.J1, SlERF.J2, and SlERF.J3, has remained largely uncharacterized. In particular, the function of SlERF.J2 in drought and salt responses and the molecular pathways under its control were previously unclear.
A study (DOI: 10.48130/els-0026-0003) published in Engineering in Life Sciences on 27 June 2026 by Guang-Long Wang's & Ai-Sheng Xiong's team, Huai'an University & Nanjing Agricultural University, reports that eliminating SlERF.J2 strengthens tomato tolerance to osmotic, drought, and salt stress by improving germination, antioxidant activity, water retention, stress-responsive gene expression, and hormone-associated regulation.
The researchers used clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 (CRISPR/Cas9) gene editing to produce three independent slerf.j2 knockout lines in the Ailsa Craig tomato background. Mutations in the first exon caused frameshifts and premature termination of protein translation. The team then tested seeds and seedlings under polyethylene glycol 6000 (PEG6000)-simulated drought, mannitol-induced osmotic stress, sodium chloride treatments, and direct drought conditions. Under 3% PEG6000, the edited lines achieved germination rates of 77%–85%, compared with 45% in wild-type plants. At 6% PEG6000, mutant germination remained at 66%–72%, whereas the wild-type rate fell to 39%. The knockout seeds also germinated earlier and reached stable germination two to three days sooner under moderate stress. Under 150 millimolar mannitol, all mutant lines developed significantly longer roots than wild-type seedlings. Even at 300 millimolar, which almost completely stopped wild-type root growth, the edited plants retained substantial root elongation. Sodium chloride experiments produced a similar pattern: mutant seeds germinated more successfully, while their seedlings maintained significantly longer roots at both 50 and 100 millimolar sodium chloride. In mature plants, the edited lines displayed less wilting and growth inhibition under drought and salt stress. They retained more leaf water and accumulated less hydrogen peroxide and malondialdehyde, indicating reduced oxidative stress and membrane damage. Their higher peroxidase activity further demonstrated stronger antioxidant defenses. Gene-expression analysis revealed increased activity in pathways related to reactive oxygen species removal, osmotic adjustment, flavonoid production, chloroplast function, light responses, cell development, and abscisic acid, gibberellin, and jasmonic acid signaling. Some hormone-related genes showed more than 20-fold higher expression under salt stress. Finally, a yeast one-hybrid assay confirmed that the SlERF.J2 protein binds directly to the promoter of SlCPS, connecting this regulator with gibberellin biosynthesis.
Overall, the study establishes SlERF.J2 as a negative regulator of tomato adaptation to drought and salinity. Removing this gene improved stress performance across germination, seedling growth, and later developmental stages without producing obvious differences under normal conditions. The work provides both a mechanistic framework for understanding ethylene response factor-mediated stress regulation and valuable germplasm for breeding resilient tomatoes. Further research should identify additional direct targets, clarify interactions among ethylene and other hormone pathways, and evaluate agronomic performance, fruit yield, and quality under field conditions before the edited material is applied commercially.
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References
DOI
10.48130/els-0026-0003
Original Source URL
https://doi.org/10.48130/els-0026-0003
Funding information
This work was supported by the Natural Science Foundation Project of Colleges and Universities in Jiangsu Province (Z413B24317), the Scientific Research Start-up project of the Huaiyin Institute of Technology (Z301B23519), the Primary Research and Development Plan (Modern Agriculture) of Jiangsu Province (BE2023350), the Priority Academic Program Development of Jiangsu Higher Education Institutions Project (PAPD), and the Bioinformatics Center of Nanjing Agricultural University.
About Engineering in Life Sciences
Engineering in Life Sciences (e-ISSN 1618-2863; p-ISSN 1618-0240) is an international source on bioengineering principles and innovations in life sciences and biotechnology, spanning biochemical engineering, process engineering, industrial chemistry. As a fully open access journal, we aim to promote global relationships among biologists, biotechnologists and bioengineers.