The superoxide dismutase genes might be required for appropriate development of the ovule after fertilization in Xanthoceras sorbifolium
Superoxide dismutase genes were expressed differentially along with developmental stages of fertilized ovules in Xanthoceras sorbifolium, and the XsMSD gene silencing resulted in the arrest of fertilized ovule development.
A very small percentage of mature fruits (ca. 5%) are produced relative to the number of bisexual flowers in Xanthoceras sorbifolium because seeds and fruits are aborted at early stages of development after pollination. Reactive oxygen species (ROS) in plants are implicated in an extensive range of biological processes, such as programmed cell death and senescence. Superoxide dismutase (SOD) activity might be required to regulate ROS homeostasis in the fertilized ovules of X. sorbifolium. The present study identified five SOD genes and one SOD copper chaperone gene in the tree. Their transcripts were differentially expressed along different stages of fertilized ovule development. These genes showed maximum expression in the ovules at 3 days after pollination (DAP), a time point in which free nuclear endosperm and nucleus tissues rapidly develop. The XsCSD1, XsFSD1 and XsMSD contained seven, eight, and five introns, respectively. Analysis of the 5′-flanking region of XsFSD1 and XsMSD revealed many cis-acting regulatory elements. Evaluation of XsMSD gene function based on virus-induced gene silencing (VIGS) indicated that the gene was closely related to early development of the fertilized ovules and fruits. This study suggested that SOD genes might be closely associated with the fate of ovule development (aborted or viable) after fertilization in X. sorbifolium.
KeywordsXanthoceras sorbifolium Fertilized ovule development Superoxide dismutase gene family Expression
We would like to thank Jie Wen and Fengqin Dong for technical help. This work was supported by the National Natural Science Foundation of China (30972344, 31370611 and 31570680) and Beijing Natural Science Foundation (6172028).
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
- Cohu CM, Abdel-Ghany SE, Gogolin Reynolds KA, Onofrio AM, Bodecker JR, Kimbrel JA, Niyogi KK, Pilon M (2009) Copper delivery by the copper chaperone for chloroplast and cytosolic copper/zinc-superoxide dismutases: regulation and unexpected phenotypes in an Arabidopsis mutant. Mol Plant 2:1336–1350. https://doi.org/10.1093/mp/ssp084 CrossRefPubMedGoogle Scholar
- Huang CH, Kuo WY, Weiss C, Jinn TL (2012) Copper chaperone-dependent and -independent activation of three copper–zinc superoxide dismutase homologs localized in different cellular compartments in Arabidopsis. Plant Physiol 158:737–746. https://doi.org/10.1104/pp.111.190223 CrossRefPubMedGoogle Scholar
- Lescot M, Dehais P, Thijs G, Marchal K, Moreau Y, Van de Peer Y, Rouze P, Rombauts S (2002) PlantCARE, a database of plant cis-acting regulatory elements and a portal to tools for in silico analysis of promoter sequences. Nucleic Acids Res 30:325–327. https://doi.org/10.1093/nar/30.1.325 CrossRefPubMedPubMedCentralGoogle Scholar
- María VM, Diego FF, Venkatesan S, Eduardo JZ, Gabriela CP (2013) Oiwa, a female gametophytic mutant impaired in a mitochondrial manganese-superoxide dismutase, reveals crucial roles for reactive oxygen species during embryo sac development and fertilization in Arabidopsis. Plant Cell 25:1573–1591. https://doi.org/10.1105/tpc.113.109306 CrossRefGoogle Scholar
- Pan SM, Hwang GB, Liu HC (1999) Over-expression and characterization of copper/zinc-superoxide dismutase from rice in Escherichia coli. Bot Bull Acad Sin (Taipei) 40:275–281Google Scholar
- Zhou QY, Zheng YR (2015) Comparative de novo transcriptome analysis of fertilized ovules in Xanthoceras sorbifolium uncovered a pool of genes expressed specifically or preferentially in the selfed ovule that are potentially involved in late-acting self-incompatibility. PLOS One 10:e0140507. https://doi.org/10.1371/journal.pone.0140507 CrossRefPubMedPubMedCentralGoogle Scholar
- Zhou QY, Zheng YR, Lai LM, Du H (2017) Observations on sexual reproduction in Xanthoceras sorbifolium (Sapindaceae). Acta Bot Occident Sin 37:0014–0022. https://doi.org/10.7606/j.issn.1000-4025.2017.01.0014 Google Scholar