It could be a tomato game-changer: Scientists have discovered a gene that would allow commercial tomato plants to tolerate 24 hours of light a day.
In theory, more light exposure means more energy production for the plant, so the discovery could lead to tomato plants that yield up to 26% more tomatoes compared with plants that are given 18 hours of light in a greenhouse setting, the Netherlands-based researchers wrote in a paper published Tuesday in the journal Nature Communications.
Scientists are not sure how widespread continuous light tolerance is throughout the plant world. Pepper plants, rose bushes and lettuces are all perfectly happy when the lights never go off, but as botanists first discovered nearly 100 years ago, tomato plants are different.
"At the beginning, yellow spots appear and they look like they need some fertilizer," said the study's lead author, Aaron Velez-Ramirez of the Laboratory of Plant Physiology at Wageningen University in the Netherlands. "If the plant is left in continuous light long enough, the complete plant turns yellow and dies."
The closest relative of domesticated tomatoes is also sensitive to continuous light, but all other strains of wild tomatoes are just fine in a world that never goes dark.
The researchers are not sure how this tolerance benefits the plants in the wild, because the lights always do go out in nature, but that is beside the point of this particular study. The main objective was to figure out which gene or set of genes was responsible for keeping wild tomato plants alive in continuous light, and to see if it could transferred to domesticated tomatoes.
Over the course of a multi-year study, the researchers found that the expression of a gene called CAB-13 seems to be a key player in bestowing light tolerance on wild tomatoes, and that this expression could be successfully transferred to commercial tomatoes over several generations of selective crossbreeding.
"It would be like crossing a dog with a wolf and then crossing back the descendants many times with dogs to get rid of all undesirable wolf characteristics but the one you want," Velez-Ramirez said.
By the end of the study, the researchers were able to grow a domesticated tomato that could tolerate 24 hours of light. They report that under those conditions, it produced 20% more fruit than plants exposed to 18 hours of light.
Their preliminary tests suggest that CAB-13 has an effect on the carbohydrate metabolism and photosynthesis of tomato plants, but it does not seem to have an effect on plant development or the fruit itself. However, more tests are needed before a 24-hour light-tolerant tomato plant will come to market.
The study was done in conjunction with researchers at Monsanto Holland, and Monsanto holds the patent on these light-tolerant tomato plants.
It should also be noted that, according to the Food and Agricultural Organization of the United Nations, production of tomatoes ranks eighth among agricultural commodities worldwide -- higher than any other fruit or vegetable.