Natural variations in the Sl‐AKR9 aldo/keto reductase gene impact fruit flavor volatile and sugar contents
Natural variations in the Sl‐AKR9 aldo/keto reductase gene impact fruit flavor volatile and sugar contents
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Sl-AKR9 醛/酮还原酶基因的自然变异影响水果风味挥发性和糖含量
DOI：
10.1111/tpj.16310
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发表时间：
2023
期刊：
影响因子：
--
通讯作者：
Klee, Harry J.
中科院分区：
文献类型：
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作者：
Li, Xiang;Tieman, Denise;Alseekh, Saleh;Fernie, Alisdair R.;Klee, Harry J.
不同水果的独特风味取决于可溶性糖、有机酸和挥发性有机化合物的复杂混合。2‐苯乙醇和苯乙醛是许多食物（包括番茄）风味的主要贡献者。在番茄果实中，葡萄糖和果糖是对人类口味偏好最积极贡献的化学物质。我们发现了一个编码番茄aldo/keto还原酶的基因Sl‐AKR9，该基因与水果中的苯乙醛和2‐苯乙醇含量有关。鉴定出两种不同的单倍型；一个编码叶绿体靶向蛋白，而另一个编码在细胞质中积累的转运肽较少的蛋白。Sl‐AKR9有效催化苯乙醛还原为2‐苯乙醇。该酶还可以代谢糖衍生的活性羰基，包括甘油醛和甲基乙二醛。CRISPR - Cas9诱导的功能缺失突变inSl - akr9显著增加了成熟果实中的苯乙醛含量，降低了2 -苯乙醇含量。在功能丧失的果实中观察到果实重量减少，可溶性固形物、葡萄糖和果糖含量增加。这些结果揭示了一种以前未被发现的影响两种风味相关的苯丙氨酸衍生的挥发性有机化合物、糖含量和水果重量的机制。现代番茄品种几乎普遍含有与更大的果实、更低的糖含量、更低的苯乙醛和2 -苯乙醇相关的单倍型，这可能导致现代品种的风味恶化。
The unique flavors of different fruits depend upon complex blends of soluble sugars, organic acids, and volatile organic compounds. 2‐Phenylethanol and phenylacetaldehyde are major contributors to flavor in many foods, including tomato. In the tomato fruit, glucose, and fructose are the chemicals that most positively contribute to human flavor preferences. We identified a gene encoding a tomato aldo/keto reductase,Sl‐AKR9, that is associated with phenylacetaldehyde and 2‐phenylethanol contents in fruits. Two distinct haplotypes were identified; one encodes a chloroplast‐targeted protein while the other encodes a transit peptide‐less protein that accumulates in the cytoplasm. Sl‐AKR9 effectively catalyzes reduction of phenylacetaldehyde to 2‐phenylethanol. The enzyme can also metabolize sugar‐derived reactive carbonyls, including glyceraldehyde and methylglyoxal. CRISPR‐Cas9‐induced loss‐of‐function mutations inSl‐AKR9significantly increased phenylacetaldehyde and lowered 2‐phenylethanol content in ripe fruit. Reduced fruit weight and increased soluble solids, glucose, and fructose contents were observed in the loss‐of‐function fruits. These results reveal a previously unidentified mechanism affecting two flavor‐associated phenylalanine‐derived volatile organic compounds, sugar content, and fruit weight. Modern varieties of tomato almost universally contain the haplotype associated with larger fruit, lower sugar content, and lower phenylacetaldehyde and 2‐phenylethanol, likely leading to flavor deterioration in modern varieties.