Exogenous β-cyclocitral treatment primes tomato plants against drought by inducing tolerance traits, independent of abscisic acid

Drought is the most devastating stress for crops. Intensity and duration of drought determine the magnitude of plant damage; similarly, plant ability to counteract drought determines its tolerance capacity. Recent studies revealed that exogenous apocarotenoid treatment confers abiotic stress tolerance to plants. However, much less is known about the role of beta-cyclocitral (beta CC), the major apocarotenoid, in drought tolerance. Here, we demonstrate beta CC's role in improving plants' tolerance against drought stress. Tomato (Solanum lycopersicum L.) plants were independently treated with water and beta CC and grown under either water-limited or irrigated conditions. The beta CC-treated drought-exposed (BD) and beta CC-treated irrigated (BH) plants were analysed for the major drought tolerance associated traits; water-treated drought-exposed (CD) and water-treated irrigated plants (CH) were used as controls. On exposure to drought, unlike controls, beta CC-treated plants showed no wilting, higher RWC and stomatal conductance, unchanged ABA levels and stomatal closure. The BD plants had increased photosynthesis, chlorophyll content and enhanced root, but not shoot, growth. In addition, beta CC treatment enhanced proline accumulation and activity of SOD in both drought-exposed and well irrigated plants. Taken together, beta CC was identified as a potential candidate that improves tomato osmolyte accumulation and superoxide elimination, independent of ABA, and prepares the plant for upcoming drought stress. Our results suggest that beta CC can be used to prime crops against drought stress.

Automated summary

The study shows that beta-cyclocitral (beta CC) can improve plant tolerance against drought stress by enhancing photosynthesis, root growth, proline accumulation, and superoxide removal in tomatoes, preparing them for upcoming drought stress.