Description of a Zostera marina catalase gene involved in responses to temperature stress

The maize ATP-binding cassette (ABC) transporter ZmMRPA6 confers cold and salt stress tolerance in plants

KEY MESSAGE

ZmMRPA6 was cloned and characterized as the first ATP-binding cassette (ABC) transporter in maize to be proven to participate in cold and salt tolerance. Homologous genes AtABCC4 and AtABCC14 of ZmMRPA6 also responded to salt stress. ATP-binding cassette (ABC) proteins are major transmembrane transporters that play significant roles in plant development against various abiotic stresses. However, available information regarding stress-related ABC genes in maize is minimal. In this study, a maize ABC transporter gene, ZmMRPA6, was identified through genome-wide association analysis (GWAS) for cold tolerance in maize seeds germination and functionally characterized. During germination and seedling stages, the zmmrpa6 mutant exhibited enhanced resistance to cold or salt stress. Mutated of ZmMRPA6 did not affect the expression of downstream response genes related cold or salt response at the transcriptional level. Mass spectrometry analysis revealed that most of the differential proteins between zmmrpa6 and wild-type plants were involved in response to stress process including oxidative reduction, hydrolase activity, small molecule metabolism, and photosynthesis process. Meanwhile, the plants which lack the ZmMRPA6 homologous genes AtABCC4 or AtABCC14 were sensitive to salt stress in Arabidopsis. These results indicated that ZmMRPA6 and its homologous genes play a conserved role in cold and salt stress, and functional differentiation occurs in monocotyledonous and dicotyledonous plants. In summary, these findings dramatically improved our understanding of the function of ABC transporters resistance to abiotic stresses in plants.

Genome-Wide Investigation and Expression Analysis of the Catalase Gene Family in Oat Plants (Avena sativa L.)

Through the degradation of reactive oxygen species (ROS), different antioxidant enzymes, such as catalase (CAT), defend organisms against oxidative stress. These enzymes are crucial to numerous biological functions, like plant development and defense against several biotic and abiotic stresses. However, despite the major economic importance of Avena sativa around the globe, little is known about the CAT gene's structure and organization in this crop. Thus, a genome-wide investigation of the CAT gene family in oat plants has been carried out to characterize the potential roles of those genes under different stressors. Bioinformatic approaches were used in this study to predict the AvCAT gene's structure, secondary and tertiary protein structures, physicochemical properties, phylogenetic tree, and expression profiling under diverse developmental and biological conditions. A local Saudi oat variety (AlShinen) was used in this work. Here, ten AvCAT genes that belong to three groups (Groups I-III) were identified. All identified CATs harbor the two conserved domains (pfam00199 and pfam06628), a heme-binding domain, and a catalase activity motif. Moreover, identified AvCAT proteins were located in different compartments in the cell, such as the peroxisome, mitochondrion, and cytoplasm. By analyzing their promoters, different cis-elements were identified as being related to plant development, maturation, and response to different environmental stresses. Gene expression analysis revealed that three different AvCAT genes belonging to three different subgroups showed noticeable modifications in response to various stresses, such as mannitol, salt, and ABA. As far as we know, this is the first report describing the genome-wide analysis of the oat catalase gene family, and these data will help further study the roles of catalase genes during stress responses, leading to crop improvement.

In Silico Methodologies to Improve Antioxidants' Characterization from Marine Organisms

Marine organisms have been reported to be valuable sources of bioactive molecules that have found applications in different industrial fields. From organism sampling to the identification and bioactivity characterization of a specific compound, different steps are necessary, which are time- and cost-consuming. Thanks to the advent of the -omic era, numerous genome, metagenome, transcriptome, metatranscriptome, proteome and microbiome data have been reported and deposited in public databases. These advancements have been fundamental for the development of in silico strategies for basic and applied research. In silico studies represent a convenient and efficient approach to the bioactivity prediction of known and newly identified marine molecules, reducing the time and costs of "wet-lab" experiments. This review focuses on in silico approaches applied to bioactive molecule discoveries from marine organisms. When available, validation studies reporting a bioactivity assay to confirm the presence of an antioxidant molecule or enzyme are reported, as well. Overall, this review suggests that in silico approaches can offer a valuable alternative to most expensive approaches and proposes them as a little explored field in which to invest.

Genome-wide analysis of the superoxide dismutase (SOD) gene family in Zostera marina and expression profile analysis under temperature stress

Superoxide dismutases (SODs) serve as the first line of defense in the plant antioxidant enzyme system, and play a primary role in the removal of reactive oxygen species (ROS). However, our understanding of the functions of the SOD family in Zostera marina is limited. In this study, a systematic analysis was conducted on the characteristics of the SOD genes in Z. marina at the whole-genome level. Five SOD genes were identified, consisting of two Cu/ZnSODs, two FeSODs, and one MnSOD. Phylogenetic analysis showed that ZmSOD proteins could be divided into two major categories (Cu/ZnSODs and Fe-MnSODs). Sequence motifs, gene structure, and the 3D-modeled protein structures further supported the phylogenetic analysis, with each subgroup having similar motifs, exon-intron structures, and protein structures. Additionally, several cis-elements were identified that may respond to biotic and abiotic stresses. Transcriptome analysis revealed expression diversity of ZmSODs in various tissues. Moreover, qRT-PCR analysis showed that the expression level of most ZmSOD genes trended to decreased expression with the increase of temperature, indicating that heat stress inhibits expression of ZmSODs and may result in reduced ability of ZmSODs to scavenge ROS. Our results provide a basis for further functional research on the SOD gene family in Z. marina, which will help to determine the molecular mechanism of ZmSOD genes in response to environmental stress.