Horticulture Department, College of Advanced Agriculture and Ecological Environment, Heilongjiang University, 74 Xuefu Road, Harbin, 150000, Heilongjiang, China.
Mol Genet Genomics. 2020 Nov;295(6):1325-1337. doi: 10.1007/s00438-020-01699-1. Epub 2020 Jun 30.
The main edible organ of snap bean (Phaseolus vulgaris L.) is the pod, whose color is a main characteristic affecting its commercial use. Golden pods are popular with consumers; however, color instability affects their commercial exploitation and causes economic losses to the planters. In this study, we focused on the different pod color of two varieties of snap bean. The golden yellow color of snap bean pods is controlled by a single recessive nuclear gene located at 1-4.24 Mb of chromosome 2. To explore the physiological and molecular mechanism of the golden pod color, the golden bean line 'A18-1' and the green bean line 'Renaya' were selected as experimental materials. We analyzed the pigment contents, detected the intermediate products of chlorophyll biosynthesis, and identified differentially expressed genes using RNA-seq. The formation of golden bean pods reflects a chlorophyll deficiency, which was speculated to be caused by impairment of the Mg-protoporphyrin IX to chlorophyllide step. In 'A18-1' and 'Renaya' pods on 10, 14, and 18 days, five genes related to this step were differentially expressed, all of which were protochlorophyllide oxidoreductase (POR) genes. Among them, the expression changes of the Phvul. 004G112700, Phvul.007G157500, and Phvul. 004G112400 genes were consistent with the color change and physiological data during pod development in 'A18-1' and 'Renaya'. We speculated that the altered expression of these three POR genes might be related to changes in the chlorophyllide content. The results might provide insight into the understanding of chlorophyll biosynthesis and crop breeding for snap bean.
菜豆的主要可食用器官是豆荚，其颜色是影响其商业用途的主要特征。金黄色豆荚深受消费者喜爱；然而，颜色不稳定影响其商业开发，并给种植者造成经济损失。在这项研究中，我们专注于两种菜豆品种的不同豆荚颜色。菜豆豆荚的金黄色由位于 2 号染色体 1-4.24 Mb 处的单个隐性核基因控制。为了探索金黄色豆荚颜色的生理和分子机制，选择了金黄色的‘A18-1’和绿色的‘Renaya’作为实验材料。我们分析了色素含量，检测了叶绿素生物合成的中间产物，并使用 RNA-seq 鉴定了差异表达的基因。金黄色豆荚的形成反映了叶绿素的缺乏，这被推测是由于 Mg-原卟啉 IX 到叶绿素的步骤受损所致。在‘A18-1’和‘Renaya’豆荚的 10、14 和 18 天，与该步骤相关的五个基因在表达上存在差异，它们都是原叶绿素氧化还原酶（POR）基因。其中，Phvul.004G112700、Phvul.007G157500 和 Phvul.004G112400 基因的表达变化与‘A18-1’和‘Renaya’豆荚发育过程中的颜色变化和生理数据一致。我们推测，这三个 POR 基因表达的改变可能与叶绿素含量的变化有关。这些结果可能有助于深入了解叶绿素生物合成和菜豆的作物育种。
