Since my childhood days, there were no supermarkets in our neighborhood. At our local farmer’s market, there was only one convenient spot to buy fresh produce. My mother would carefully choose the plumpest, most vibrant tomatoes and gently cook them with eggs, transforming them into a comforting culinary masterpiece that has since become my go-to solace food.
The tomatoes had been an unappealing sight – undersized, distorted, and poorly hued, bearing little resemblance to the luscious, plump, and vibrantly colored beefsteak and Roma varieties that would eventually dominate supermarket shelves. While I’ve found them delightfully flavorful, the perfect balance of tangy and sweet notes creates a thrilling experience on my palate.
In recent years, whenever I request a familiar dish, my mother always remarks, “Tomatoes just aren’t as flavorful now.”
She’s not alone. I’ve found that the immediate’s produce is often lacking in flavor and texture, with a noticeable wateriness and waxy consistency, regardless of its initial appearance as ripe and appealing. That’s because breeding was done in this way. Today’s crops are often genetically engineered to prioritize traits such as appearance, size, shelf life, and transportation efficiency. While offering such perks may compromise on aesthetic appeal, particularly in the case of sugary treats. Despite its reputation for bitterness, certain broccoli varieties have evolved to store sugar in their stems, resulting in a subtly sweeter flavour profile.
Researchers at Shenzhen’s Sanwen Huang-led team have discovered a fascinating correlation: larger fruit sizes can surprisingly result in significantly reduced candy content. The key to breaking this connection is to interrupt that correlation. He developed a method utilizing tomatoes, a globally popular crop, as an exemplar.
Researchers have isolated a specific gene set from both wild and cultivated tomato varieties that regulates sugar production by acting as a brake. By harnessing the precision of the preferred gene-editing tool, researchers successfully boosted the fruit’s natural sugar levels by 30% – a substantial increase that was perceptible to consumer panels – without compromising size or yield.
As edited seeds germinated normally, the experiment could proceed to subsequent generations without hindrance.
The examination isn’t quite scratching our sweet tooth. Crops with higher sugar content, such as those containing larger amounts of sucrose or fructose, naturally possess more calories, which are essential for supporting the growth and development of plants. The evaluation pipeline developed in the study is poised to investigate various genetic trade-offs between size and diet, ultimately facilitating rapid breeding of enhanced crops.
“The study represents a thrilling leap forward for crop improvement globally,” said Amy Lanctot and Patrick Shih of the University of California, Berkeley, who were not involved in the research.
Scorching Hyperlinks
For millennia, humans have selectively bred crops to enhance desirable traits – such as increased yields, broader dietary value, and appearances.
Tomatoes are an ideal instance. The fruit is widely regarded as the most valuable vegetable crop globally, making significant contributions to both overall health and dietary intake in the human food system. Wild varieties of fruit and vegetables exhibit a broad range of sizes, from cherries to peas, significantly smaller than the typical specimens found in most supermarkets. Flavours are generated by the binding of two types of sugars to their specific receptors.
Despite millennia of selective breeding, sugar remains the crucial component that elevates the flavor profile of tomatoes. In recent years, breeders have primarily focused on increasing fruit size. The ultimate outcome is the production of tomatoes that are either straightforwardly sliced for sandwich applications, pulverized for canning purposes, or further refined into a range of products including various sauces and pastes. Compared to their untamed predecessors, today’s domesticated tomatoes have grown significantly larger, varying from a 10- to 100-fold increase in size, thereby rendering them notably more cost-effective.
However, these enhancements bring a tangible value. As we delve into the realm of higher dimensions, a surprising correlation emerges: as the number of dimensions increases, sugar content declines, while taste intensity plummets? Significant advancements have also occurred in various large-scale farming practices related to fruit cultivation.
Researchers have been endeavouring to uncover the intricacies of the tomato’s internal mechanisms, focusing on genes responsible for sugar production to revitalize its nutritional value and aesthetic appeal. In 2017, researchers conducted a comprehensive mixed-genomic analysis of nearly 400 tomato varieties, leveraging human taste panels and advanced metabolomics techniques to identify key chemical compounds responsible for enhancing the flavor profile of this iconic fruit. Twelve months after, Huang’s team, having spearheaded a groundbreaking study, successfully cultivated an astonishing array of hundreds of tomato varieties through cell-based operations. The domestication process involved significant genomic changes, but the team lacked insight into how each genetic mutation impacted the fruit’s metabolic processes.
While genetic variants are often linked to specific traits, it’s more accurate to state that there is an association between the two rather than stating outright causality; thus: Our genetic material, comprising tightly coiled DNA strands, is organized into distinctive X-shaped structures known as chromosomes. Like intricately woven skeins of thread, these three-dimensional structures compactly coalesce genetic material typically dispersed along a linear chromosome. Genes that are physically close together tend to turn on or off simultaneously, often referred to as a genetic module.
“While genetic linkage poses a challenge in modifying one gene without impacting others, researchers like Lanctot and Shih have grappled with this complexity.”
Quick Observe Evolution
The groundbreaking study leveraged a novel combination of innovative technologies to successfully overcome the challenge.
The advent of affordable genetic sequencing technologies revolutionized the field. Researchers identified six key genes responsible for the sweet flavor of domesticated tomatoes by comparing genetic variations with those found in their wild counterparts.
Their attention was drawn to a specific gene. In sweeter tomato varieties, a shutdown occurred, halting the process of sugar accumulation in the vegetation. Scientists employed the precise gene-editing technology CRISPR-Cas9 to modify the target gene, rendering it inactive, and cultivated both genetically modified and non-modified organisms under consistent environmental conditions in a controlled garden setting.
The Candy Spot
Approximately one hundred volunteers participated in a blind taste test, comparing both edited and regular tomatoes. The CRISPRed tomatoes garnered widespread acclaim for their exceptional sweetness.
Isn’t that an examination about a larger tomato? The analysis uncovers the untold value residing within the genomes of crop species varieties and their wild relatives.
While domestication may increase yields or size of a fruit, it often comes at the cost of reducing genetic diversity within a species, as cultivated varieties tend to share similar genetic blueprints. While some crops share characteristics with bananas, such as the inability to reproduce independently, they also exhibit heightened vulnerability to fungal infections. Investigating the genetic components linked to these characteristics could facilitate the development of a preventive strategy.
Scientists have also endeavored to imbue crops with novel characteristics beyond mere conservation and style considerations. Sanatech Seed, a Japanese-based organization, leveraged CRISPR-Cas9 technology in 2021 to amplify the production of a key compound that modulates neural transmission. Tomatoes have been found to help reduce blood pressure and promote relaxation in individuals, potentially assisting people in calming down. Following regulatory approval in Japan, the fruit is now widely available on the market.
While research that directly link a specific gene to a particular trait in plants are still relatively rare? Thanks to advances in affordable and rapid DNA sequencing technologies and precise CRISPR tools, it is becoming increasingly easier to investigate these relationships.
“As researchers delve deeper into the genetic mechanisms governing trade-offs, they are increasingly leveraging cutting-edge genome-editing tools to untangle these complexities and boost key agricultural attributes,” wrote Lanctot and Shih.
