Ancestor of land plants acquired the DNA-3-methyladenine glycosylase (MAG) gene from bacteria through horizontal gene transfer

Abstract

The origin and evolution of land plants was an important event in the history of life and initiated the establishment of modern terrestrial ecosystems. From water to terrestrial environments, plants needed to overcome the enhanced ultraviolet (UV) radiation and many other DNA-damaging agents. Evolving new genes with the function of DNA repair is critical for the origin and radiation of land plants. In bacteria, the DNA-3-methyladenine glycosylase (MAG) recognizes of a variety of base lesions and initiates the process of the base excision repair for damaged DNA. The homologs of MAG gene are present in all major lineages of streptophytes, and both the phylogenic and sequence similarity analyses revealed that green plant MAG gene originated through an ancient horizontal gene transfer (HGT) event from bacteria. Experimental evidence demonstrated that the expression of the maize ZmMAG gene was induced by UV and zeocin, both of which are known as DNA-damaging agents. Further investigation revealed that Streptophyta MAG genes had undergone positive selection during the initial evolutionary period in the ancestor of land plants. Our findings demonstrated that the ancient HGT of MAG to the ancestor of land plants probably played an important role in preadaptation to DNA-damaging agents in terrestrial environments.

Proteomic Response of Pseudomonas putida KT2440 to Dual Carbon-Phosphorus Limitation during mcl-PHAs Synthesis

“…The experimental results showed a decreased abundance of DNA gyrase along with the repression of cell division protein FtsZ (spot 1834; p-value = 4.788 × 10 −4 ) that influenced the low P. putida KT2440 growth level and as a consequence the low content of mcl-PHAs in bacterial cells. These observations were previously described by Guha et al [41], who showed that gyrase depletion altered ftsZ expression in Mycobacterium smegmatis, leading to slower growth. Furthermore, at the same time point (48 h), the abundance of DNA-3-methyladenine glycosylase (spot 2591; p-value = 0.003) was increased.…”

“…Furthermore, at the same time point (48 h), the abundance of DNA-3-methyladenine glycosylase (spot 2591; p-value = 0.003) was increased. This protein participates in the initiation of the base excision repair process of damaged DNA [41].…”

Emergence of Intronless Evolutionary Forms of Stress Response Genes: Possible Relation to Terrestrial Adaptation of Green Plants

“…Potentially, retrotransposition appears to enrich the genome with large numbers of duplicate retrocopies that can act as a source for both new composite genes in the same species and new genomic sequences in foreign species. It should be noted that acquisition of intronless genes could occur without a reverse transcription event, possibly by introgression of bacterially encoded sequences in plant genomes, as it has been suggested in several studies (Emiliani et al, 2009; Yue et al, 2012; Yang et al, 2014; Hu et al, 2016; Fang et al, 2017).…”

“…Evolutionary details of exon-intron organization in these genes are not analyzed comprehensively, although such an analysis would be rather informative and important for understanding their evolutionary history. Particularly, a series of papers on Phragmoplastophyta stress-related intron-containing genes show their origin by horizontal gene transfer of intronless prokaryotic genes (Emiliani et al, 2009; Fang et al, 2017).…”

“…What could be the primary fuction(s) and the origin of intronless genes in the genome of C. braunii ? Assuming our recent data on the involvement of Nt-4/1 protein into stress responses (Atabekova et al, 2018), we hypothesize that acquisition and fixation of 4/1-like genes, as well as other stress-related genes, in charophyte genomes might contribute to terrestrial adaptation of green plants subjected to many new stress factors such as brighter sunlight (UV radiation), lack of efficient support against gravity, dehydration, and high carbon dioxide levels in the atmosphere (Fang et al, 2017; Pierangelini et al, 2017, 2018). In fact, C. braunii genome is found to encode a number of evolutionary novel, compared to aquatic green algae, genes related to plant terrestrialization, particularly, genes responsible for reactive oxygen species scavenging (Nishiyama et al, 2018).…”