ABSTRACT
The perennial herb Heuchera micrantha (Saxifragaceae) is a popular ornamental plant. However, the plastome sequence of H. micrantha has not been reported yet. Here, we assembled the complete plastome of H. micrantha using Illumina high-throughput pair-end sequencing. The plastome is a circular DNA molecule of 155,469 bp, comprising a pair of inverted repeat (IR, 25,654 bp) regions, a small single copy (SSC, 18,050 bp) region, and a large single copy (LSC, 86,111 bp) region. It encodes 129 genes, of which 84 are protein-coding genes, 37 are transfer RNAs, and eight are rRNAs. The total GC content is 37.8%. Phylogenetic analysis shows that H. micrantha, together with three other Heuchera species is clustered with Tiarella cordifolia. This complete plastome is beneficial for future genetic research on the Heuchera group.
ABSTRACT
An 888-bp full-length ascorbate peroxidase (APX) complementary DNA (cDNA) gene was cloned from Anthurium andraeanum, and designated as AnAPX. It contains a 110-bp 5'-noncoding region, a 28-bp 3'-noncoding region, and a 750-bp open reading frame (ORF). This protein is hydrophilic with an aliphatic index of 81.64 and its structure consisting of α-helixes, ß-turns, and random coils. The AnAPX protein showed 93%, 87%, 87%, 87%, and 86% similarities to the APX homologs from Zantedeschia aethiopica, Vitis pseudoreticulata, Gossypium hirsutum, Elaeis guineensis, and Zea mays, respectively. AnAPX gene transcript was measured non-significantly in roots, stems, leaves, spathes, and spadices by real-time polymerase chain reaction (RT-PCR) analysis. Interestingly, this gene expression was remarkably up-regulated in response to a cold stress under 6 °C, implying that AnAPX might play an important role in A. andraeanum tolerance to cold stress. To confirm this function we overexpressed AnAPX in tobacco plants by transformation with an AnAPX expression construct driven by CaMV 35S promoter. The transformed tobacco seedlings under 4 °C showed less electrolyte leakage (EL) and malondialdehyde (MDA) content than the control. The content of MDA was correlated with chilling tolerance in these transgenic plants. These results show that AnAPX can prevent the chilling challenged plant from cell membrane damage and ultimately enhance the plant cold tolerance.
