State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, 455000, Henan, China.
College of Life Sciences, Xinyang Normal University, Xinyang, 464000, Henan, China.
Theor Appl Genet. 2019 Jul;132(7):2069-2086. doi: 10.1007/s00122-019-03338-9. Epub 2019 Apr 5.
The vsp gene was fine mapped to a 353.7-kb region, and a 201-bp deletion that affected chloroplast development and chlorophyll biosynthesis was found in the candidate gene GhPUR4. Virescent mutations can be used as marker traits in heterosis breeding and can also be used to research chloroplast development, chlorophyll biosynthesis and photosynthesis mechanisms. Here, we obtained a light-sensitive virescent mutant, vsp, that has reduced chlorophyll (Chl) content and abnormal chloroplast development. Then, the virescent space (vsp) gene in the vsp mutant was preliminarily mapped to a 38.32-Mb region of chromosome D04 using a high-density SNP genetic map with a total length of 5384.33 cM and 4472 bin markers. Furthermore, the vsp gene was narrowed down to a 353.7-kb region that contains 15 candidate genes using 484 virescent individuals from an F population. Sequence analysis of genes in this region showed that a 201-bp deletion was present in the Gh_D04G1108 (GhPUR4) gene in the vsp mutant. The 201-bp deletion of Gh_D04G1108 caused the deletion of 67 AAs in the GhPUR4 protein. Virus-induced gene silencing (VIGS) of GhPUR4 in normal plants caused reduced GhPUR4 gene expression levels, reduced Chl content, abnormal chloroplast development and virescent true leaves. This study could help us unravel the function of GhPUR4 in chloroplast development and Chl biosynthesis at the early developmental stages of the true leaves in cotton, which could promote the research and application of virescent mutations in cotton heterosis breeding.
vsp 基因被精细定位到一个 353.7kb 的区域，在候选基因 GhPUR4 中发现了一个影响叶绿体发育和叶绿素生物合成的 201bp 缺失。绿色突变体可用作杂种优势育种中的标记性状，也可用于研究叶绿体发育、叶绿素生物合成和光合作用机制。在这里，我们获得了一个对光敏感的绿色突变体 vsp，该突变体的叶绿素（Chl）含量降低，叶绿体发育异常。然后，利用总长度为 5384.33cM 和 4472 个 bin 标记的高密度 SNP 遗传图谱，将 vsp 突变体中的绿色空间（vsp）基因初步定位到染色体 D04 的 38.32Mb 区域。此外，利用来自 F 群体的 484 个绿色个体，将 vsp 基因缩小到一个包含 15 个候选基因的 353.7kb 区域。对该区域基因的序列分析表明，vsp 突变体中 Gh_D04G1108（GhPUR4）基因存在 201bp 的缺失。Gh_D04G1108 的 201bp 缺失导致 GhPUR4 蛋白中 67 个氨基酸的缺失。在正常植物中，GhPUR4 的病毒诱导基因沉默（VIGS）导致 GhPUR4 基因表达水平降低、Chl 含量降低、叶绿体发育异常和绿色真叶。本研究有助于揭示 GhPUR4 在棉花真叶早期发育阶段叶绿体发育和 Chl 生物合成中的功能，促进绿色突变在棉花杂种优势育种中的研究和应用。
