Key Laboratory of Horticulture Science for Southern Mountainous Regions, Ministry of Education, College of Horticulture and Landscape Architecture, Southwest University, No.2 Tiansheng Road, Beibei, Chongqing 400715, China.
State Cultivation Base of Crop Stress Biology for Southern Mountainous land of Southwest University, Academy of Agricultural Sciences, Southwest University, Beibei, Chongqing 400715, China.
Int J Mol Sci. 2019 Jun 25;20(12):3102. doi: 10.3390/ijms20123102.
Some lipoxygenase (LOX) isoenzymes can co-oxidize carotenoids. Carotenoids are collectors of light energy for photosynthesis and can protect plants from reactive oxygen species and coloration. This study isolated the cucumber ( L.) yellow-green leaf mutant (), which had yellow-green leaves with decreased chlorophyll synthesis, increased relative carotenoid content, and delayed chloroplast development. Genetic analysis demonstrated that the phenotype of was caused by a recessive mutation in a nuclear gene. The bulked segregants were resequenced, and the candidate locus identified was mapped to the 9.2 kb region of the chromosome 4. Sequence analysis revealed that encodes the tandem genes in a cluster. Four missense mutations were found in four tandem genes (, , , and ) in the mutant, and the four genes showed high similarity with one another. The transient RNA interference and virus-induced gene silencing of these genes simultaneously resulted in yellow-green leaves with a reduced amount of chloroplasts and increased relative carotenoid content, which were observed in the mutant. This evidence supported the non-synonymous SNPs (Single Nucleotide Polymorphism) in the four tandem genes as being the causative mutation for the yellow-green leaves. Furthermore, this study provides a new allele for breeding cucumbers with yellow-green leaves and serves as an additional resource for studying carotenoid biosynthesis.
一些脂氧合酶 (LOX) 同工酶可以共同氧化类胡萝卜素。类胡萝卜素是光合作用的光能收集器，可保护植物免受活性氧和变色的影响。本研究分离到黄瓜（L.）黄绿叶突变体（），其叶片呈黄绿，叶绿素合成减少，相对类胡萝卜素含量增加，叶绿体发育延迟。遗传分析表明，的表型是由一个核基因的隐性突变引起的。对混池进行重测序，并将候选 定位到染色体 4 的 9.2 kb 区域。序列分析表明，编码串联 基因在一个基因簇中。在 突变体的四个串联 基因（、、、和）中发现了四个错义突变，这四个 基因彼此之间高度相似。这些基因的瞬时 RNA 干扰和病毒诱导的基因沉默同时导致了叶绿体数量减少和相对类胡萝卜素含量增加的黄绿叶表型，这在 突变体中观察到。这一证据支持四个串联 基因中的非同义 SNP（单核苷酸多态性）是导致黄绿叶的致病突变。此外，本研究为培育黄绿叶黄瓜提供了一个新的等位基因，并为研究类胡萝卜素生物合成提供了额外的资源。
