Tomato ( Solanum lycopersicum L.) is one of the most widely cultivated and consumed vegetables globally. Its fruits is highly valued for its vibrant color, culinary versatility, and nutritional benefits.In particular, its fragrance significantly enhances the sensory appeal and flavor quality of fruits, influencing the consumption and market price of tomatoes.
Notably, 2-acetyl-1-pyrroline (2-AP) is a dominant VOC (volatile organic compound) responsible for the delightful "popcorn-like" aroma. This fragrance is produced by loss-of-function mutations in the betaine aldehyde dehydrogenase 2 ( BADH2 ) gene. In fragrant varieties, the disrupted activity of BADH2 leads to accumulation of GABald, which is subsequently converted to 2-AP. However, no natural popcorn-like fragrant tomato genotype has yet been discovered, and centuries of domestication and intensive breeding have systematically eroded flavor in commercial cultivars.
To that end, a team of researchers from China and Australia generated the first extraordinary aromatic tomato plants by simultaneously mutating both SlBADH1 and SlBADH2 in tomato varieties genes using CRISPR/Cas9 .
They reported their results in the Journal of Integrative Agriculture .
“To identify BADH2 homologs in tomato, we screened the tomato reference genome, two putative SlBADH genes were identified in tomato, defined as SlBADH1 and SlBADH2 , respectively,” shares corresponding author Shengchun Xu, a professor at Xianghu Laboratory, China. “The CRISPR/Cas9‐mediated genome editing technology was used to knock out individual or both SlBADH1 and SlBADH2 gene in the variety AC (Alisa Craig).”
The team's results showed that the slbadh2 but not the slbadh1 single mutant lines exhibited a significantly higher 2‐AP contents. Notably, 2‐AP content in both leaves and fruits of the double mutants was over four times higher than those in the slbadh2 single mutants. “These results indicated that although SlBADH2 played a predominant role in regulating the 2‐AP accumulation in tomato, SlBADH1 also significantly contributed to this regulatory process,” says Xu.
None of the six single or double mutant lines differed significantly from the wild type (WT) for any key agronomic or quality trait including flowering time, plant height, fruit weight, soluble sugars (glucose, fructose, sucrose), organic acids (citric and malic acid), or vitamin C content, achieving the goal of ‘flavor improvement without yield loss’.
“We generated the first extraordinary aromatic tomato plants by simultaneously mutating both SlBADH1 and SlBADH2 genes in tomato varieties using CRISPR/Cas9. Ongoing work aims to introduce this fragrance to elite commercial cultivars, which may enhance their flavor complexity, potentially improving consumer preference and market value, like fragrant rice varieties.” shares the co-first author Peng Zheng, an associate professor at Xianghu Laboratory.
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Contact the author:Correspondence Shengchun Xu xushengchun@xhlab.ac.cn, Jingyin Yu, yujingyin@xhlab.ac.cn
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Journal of Integrative Agriculture
Experimental study
Cells
Generating popcorn-like fragrant tomato using CRISPR/Cas9-mediated gene editing
The authors declare that they have no conflict of interest.