College of Horticulture, Sichuan Agricultural University, Chengdu, 611130, China.
Institute of Pomology and Olericulture, Sichuan Agricultural University, Chengdu, 611130, China.
Sci Rep. 2019 Oct 30;9(1):15670. doi: 10.1038/s41598-019-52276-5.
Citrus species are among the most economically important fruit crops. Physiological characteristics and molecular mechanisms associated with de-etiolation have been partially revealed. However, little is known about the mechanisms controlling the expression and function of genes associated with photosynthesis and chlorophyll biosynthesis in variegated citrus seedlings. The lower biomass, chlorophyll contents, and photosynthetic parameter values recorded for the variegated seedlings suggested that chlorophyll biosynthesis was partially inhibited. Additionally, roots of the variegated seedlings were longer than the roots of green seedlings. We obtained 567.07 million clean reads and 85.05 Gb of RNA-sequencing data, with more than 94.19% of the reads having a quality score of Q30 (sequencing error rate = 0.1%). Furthermore, we detected 4,786 and 7,007 differentially expressed genes (DEGs) between variegated and green Shiranuhi and Huangguogan seedlings. Thirty common pathways were differentially regulated, including pathways related to photosynthesis (GO: 0015979) and the chloroplast (GO: 0009507). Photosynthesis (44 and 63 DEGs), photosynthesis-antenna proteins (14 and 29 DEGs), and flavonoid biosynthesis (16 and 29 DEGs) pathways were the most common KEGG pathways detected in two analyzed libraries. Differences in the expression patterns of PsbQ, PetF, PetB, PsaA, PsaN, PsbP, PsaF, Cluster-2274.8338 (ZIP1), Cluster-2274.38688 (PTC52), and Cluster-2274.78784 might be responsible for the variegation in citrus seedlings. We completed a physiological- and transcriptome-level comparison of the Shiranuhi and Huangguogan cultivars that differ in terms of seedling variegation. We performed mRNA-seq analyses of variegated and green Shiranuhi and Huangguogan seedlings to explore the genes and regulatory pathways involved in the inhibition of chlorophyll biosynthesis and decreases in Chl a and Chl b contents. The candidate genes described herein should be investigated in greater detail to further characterize variegated citrus seedlings.
柑橘属植物是最具经济价值的水果作物之一。已经部分揭示了与脱黄化相关的生理特征和分子机制。然而，关于控制与光合作用和叶绿素生物合成相关基因表达和功能的机制，人们知之甚少。斑驳柑橘幼苗的生物量、叶绿素含量和光合参数值较低表明，叶绿素生物合成受到部分抑制。此外，斑驳幼苗的根比绿苗的根长。我们获得了 567070000 条清洁读数和 8505050000 个 RNA 测序数据，超过 94.19%的读数质量得分为 Q30（测序错误率=0.1%）。此外，我们在斑驳和绿皮 Shiranuhi 和黄冠柑幼苗之间检测到 4786 和 7007 个差异表达基因（DEGs）。有 30 个共同途径受到差异调控，包括与光合作用（GO：0015979）和叶绿体（GO：0009507）相关的途径。在两个分析文库中，检测到最常见的 KEGG 途径是光合作用（44 和 63 个 DEGs）、光合作用天线蛋白（14 和 29 个 DEGs）和类黄酮生物合成（16 和 29 个 DEGs）途径。PsbQ、PetF、PetB、PsaA、PsaN、PsbP、PsaF、Cluster-2274.8338（ZIP1）、Cluster-2274.38688（PTC52）和 Cluster-2274.78784 的表达模式差异可能是柑橘幼苗斑驳的原因。我们完成了 Shiranuhi 和 Huangguogan 品种在幼苗斑驳方面的生理和转录组水平比较。我们对斑驳和绿皮 Shiranuhi 和 Huangguogan 幼苗进行了 mRNA-seq 分析，以探讨参与叶绿素生物合成抑制和 Chl a 和 Chl b 含量降低的基因和调控途径。本文描述的候选基因应进行更详细的研究，以进一步表征斑驳柑橘幼苗。
