Endocellulase SlGH9-21 significantly improves drought resistance and storage capacity of tomato

Drought, one of the most important abiotic factors affecting plant growth, causes a large reduction in tomato production every year. Tomato, a berry fruit and vegetable that can be eaten fresh or cooked, has rich nutritional value. However, most of ripe fruits show softening of pericarp, which leads to damage easily during transportation, and shorten the shelf life. Fruit mechanical strength is important to the texture, transport resistance and shelf life of tomato fruit. We found a natural tomato mutant in the field, which showed excellent drought resistance ability and late ripening characteristics. The target gene Solyc09g075360 (SlGH9-21) was obtained through transcriptome data screening. After the gene was silenced, tomatoes improved their drought resistance by reducing stomatal aperture and increasing stem vessel diameter. We also found that silencing of the SlGH9-21 gene delayed the ripening of tomato fruit and improved fruit firmness. Compared with the control, the ripening of the fruit of SlGH9-21 gene-silenced plants was delayed by approximately 10 days, which increased the fruit firmness and storage tolerance and reduced the water loss rate of fruit. Overall, the study of tomato stress response mechanisms and the identification of key genes regulating fruit hardness are beneficial to the improvement of tomato resistance. It is also conducive to the improvement of tomato quality. The research results can lay a foundation for the enhancement of fruit storage tolerance and stress resistance.