西瓜中苹果酸代谢关键基因 NADP/ME 的克隆及功能分析

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中图分类号：S651 文献标志码：A 文章编号：1673-2871（2025）09-040-08

Cloning and functional analysis of NADP-ME， a key gene in malic acid metabolism inwatermelon

DONG Wei'，YANG Congji'， XU Shouming'， ZHANG Zhou'，WU Defeng'，LI Junhua² （1.Collgeifitnded ences，Kaifeng475004，Henan，China）

Abstract：Organicacids in watermelon fruitsare critical components influencing flavorquality，and elucidating the molecular mechanismofmalicacid synthesisand metabolism isof greatsignificance.Through homologous sequence alignment，two watermelon NADP-malic enzyme genes，designated as ClaNADP-ME3 and ClaNADP-ME4，were cloned. Quantitativereal-timePCR（qRT-PCR）and high-performance liquidchromatography（HPLC）analysis revealedthatthe expression levelof ClaNADP-ME4 was negativelycorelated the the malicacid content in watermelon.Subcellularlocalizationanalysisusing GFPfusion proteinsdemonstrated thatthe ClaNADP-ME4 gene Was distributed in boththecytoplasm andnucleus.Genetic transformationandoverexpressionof the ClaNADP-ME4gene furtherconformed its function，demonstratingthatthis gene significantlyreducedthemalicacidcontentin watermelon fruits.Inconclusion，theNADP-ME4 gene plays a role in promoting malic acid metabolism.These findings provide a new target for molecular breding aimed at improvingwatermelonquality.

Keywords：Watermelon;Malicacid;NADP-malic enzyme;Overexpression

果实中的pH及可溶性固形物、苹果酸和柠檬酸含量都是影响西瓜风味的重要因素。（剩余10447字）